Showing 1–50 of 97 results for author: Gong, H

Exponential multi-graylevel computational-weighted dithering for high-quality binarized Fourier single-pixel imaging

Authors: Qigao Zhu, Haojia Jiang, Guan Wang, Lianhao Zhang, Hanlei Gong, Huaxia Deng, Xinglong Gong

Abstract: Binarized Fourier single-pixel imaging (FSI) takes full advantage of the high modulation speed of digital micromirror devices by applying Floyd-Steinberg spatial dithering to binarize grayscale Fourier patterns. However, the use of the spatial dithering introduces substantial quantization errors, leading to decreasing imaging quality. Here, we propose a binarization method for grayscale Fourier pa… ▽ More Binarized Fourier single-pixel imaging (FSI) takes full advantage of the high modulation speed of digital micromirror devices by applying Floyd-Steinberg spatial dithering to binarize grayscale Fourier patterns. However, the use of the spatial dithering introduces substantial quantization errors, leading to decreasing imaging quality. Here, we propose a binarization method for grayscale Fourier patterns based on exponential multi-graylevel computational-weighted dithering, aimed at reducing quantization errors and then enhancing the imaging quality of binarized FSI. The proposed method quantizes Fourier patterns into $2^{R}$ values $\{0, 1/(R-1), 2/(R-1)... 1\}$ and then decomposes them into binarized patterns. Both simulation and experimental results demonstrate that the method significantly reduces quantization errors in Fourier coefficients acquisition and improves imaging quality. The mean absolute percentage error of Fourier coefficients decreases from $194\%$ to $28\%$ and the structural similarity of reconstructed images ($256\times256$ pixels) improves from 0.430 to 0.971, a $126\%$ enhancement compared to the conventional method. Lateral resolution of this proposed method almost approaches the theoretical lateral resolution limit calculated by Rayleigh Criterion. △ Less

Submitted 13 August, 2026; originally announced August 2026.

Effects of Nozzle Roughness on the Streamwise Streaks in Underexpanded Jets -- An Experimental Study

Authors: Haohan Gong, Shengkai Wang

Abstract: The present study investigated the formation of streamwise streaks in underexpanded jets from round sonic nozzles, based on direct experimental observation using high-speed schlieren imaging and PLIF methods. The effect of geometric perturbations of the nozzle exit on the streamwise flow structure was examined through a series of comparative experiments. Underexpanded jets were generated in a vacu… ▽ More The present study investigated the formation of streamwise streaks in underexpanded jets from round sonic nozzles, based on direct experimental observation using high-speed schlieren imaging and PLIF methods. The effect of geometric perturbations of the nozzle exit on the streamwise flow structure was examined through a series of comparative experiments. Underexpanded jets were generated in a vacuum chamber using phi-4 mm nozzles of two different configurations: (a) a "smooth" nozzle, shaped and polished by a high-quality commercial lathe machine; and (b) nozzles with artificially introduced sinusoidal perturbation of various wavenumbers on the circular contour of the exit. In the case of the "smooth" nozzle, experiments were repeated following a 60-degree rotation of the nozzle along its axis, and a similar rotation in the streak patterns was observed. This suggests that the streamwise streaks most likely originated from geometric perturbations caused by the minute roughness at the nozzle exit. In the latter case, the effects of modal distribution of geometric perturbation on the streaks were further investigated. The results showed that the low-wavenumber (k < 5) perturbations exhibited much smaller growth rates of streamwise streaks - likely dominated by residual roughness similar to the "smooth" case - compared to higher-wavenumber (k = 6 and 7) perturbations, where the streak patterns were observed to correlate geometrically with the perturbed nozzle exit contour. Results from the present study should prove useful in enhancing the current understanding of noise patterns in supersonic wind tunnel tests, where nozzles are critical components. △ Less

Submitted 9 April, 2026; originally announced April 2026.

Probabilistic reconstruction of global sea surface temperature using generative diffusion models

Authors: Haijie Li, Ya Wang, Kai Yang, Gang Huang, Xiangao Xia, Ziming Chen, Weichen Tao, Chenglin Lyu, Lin Chen, Miao Zhang, Kaiming Hu, Hainan Gong, Disong Fu, Lin Wang

Abstract: Accurate reconstruction of global Sea surface temperature (SST), which dominates the air-sea coupling and global climate variability, underpins climate monitoring and prediction. Existing SST reconstruction products primarily provide one deterministic field derived from heterogeneous satellite data and in situ observations, limiting their ability to represent observation uncertainty and to support… ▽ More Accurate reconstruction of global Sea surface temperature (SST), which dominates the air-sea coupling and global climate variability, underpins climate monitoring and prediction. Existing SST reconstruction products primarily provide one deterministic field derived from heterogeneous satellite data and in situ observations, limiting their ability to represent observation uncertainty and to support probabilistic forecasting. Here, we introduce Satellite and in situ Adaptive Guided Estimation (SAGE), a diffusion-based uncertainty-aware generative framework for probabilistic SST reconstruction. SAGE learns a physically consistent prior from historical SST data and performs observation-conditioned posterior sampling without requiring satellite or in situ data during training, enabling flexible state inference from heterogeneous observations. Through a progressive data-fusion strategy, observations from two FengYun-3D polar-orbiting satellites constrain basin-scale structures, while sparse in situ measurements serve to refine local anomalies and extremes. The resulting ensemble SST fields well capture observational uncertainty and scale-dependent variability. Validation against independent in situ observations shows that SAGE substantially reduces reconstruction errors compared with widely used operational products. When used to initialize forecasting systems, SAGE-generated SST fields substantially reduce 10-day SST forecast errors relative to current operational analyses. At the climate scale, SAGE-driven forecasts of the 2023-2024 El Nino event show added value in capturing its onset and intensity evolution compared to conventional approaches. Our results demonstrate that SAGE represents a step toward a new paradigm for ocean state estimation and climate prediction. △ Less

Submitted 23 March, 2026; v1 submitted 17 March, 2026; originally announced March 2026.

Search for Cosmic Ray Electron Boosted Dark Matter with the CDEX-10 Experiment

Authors: R. Xu, L. T. Yang, Q. Yue, K. J. Kang, Y. J. Li, H. P. An, Greeshma C., J. P. Chang, H. Chen, Y. H. Chen, J. P. Cheng, J. Y. Cui, W. H. Dai, Z. Deng, Y. X. Dong, C. H. Fang, H. Gong, Q. J. Guo, T. Guo, X. Y. Guo, L. He, J. R. He, H. X. Huang, T. C. Huang, S. Karmakar , et al. (63 additional authors not shown)

Abstract: We present new constraints on the cosmic ray electron boosted light dark matter (CReDM) using the 205.4 kg$\cdot$day data of the CDEX-10 experiment located at the China Jinping Underground Laboratory. The cosmic ray electron spectrum and distribution in the Galaxy are generated by the $\tt GALPROP$ code package. In the calculation process of DM-electron scattering process in the Galaxy, we conside… ▽ More We present new constraints on the cosmic ray electron boosted light dark matter (CReDM) using the 205.4 kg$\cdot$day data of the CDEX-10 experiment located at the China Jinping Underground Laboratory. The cosmic ray electron spectrum and distribution in the Galaxy are generated by the $\tt GALPROP$ code package. In the calculation process of DM-electron scattering process in the Galaxy, we consider the energy-dependency of the DM-electron scattering cross section. The constraints on CReDM are set for both heavy and light mediator scenarios using the CDEX-10 dataset. The result exceeds previous Standard Halo Model (SHM) limits for DM mass lower than 0.6 MeV in heavy mediator case and corresponds to the best sensitivity among all direct detection experiments from 1 keV to 0.5 MeV in the light mediator scenario. △ Less

Submitted 13 January, 2026; originally announced January 2026.

Comments: 7 pages, 5 figures

Initial performance results of the JUNO detector

Authors: Angel Abusleme, Thomas Adam, Kai Adamowicz, David Adey, Shakeel Ahmad, Rizwan Ahmed, Timo Ahola, Sebastiano Aiello, Fengpeng An, Guangpeng An, Costas Andreopoulos, Giuseppe Andronico, João Pedro Athayde Marcondes de André, Nikolay Anfimov, Vito Antonelli, Tatiana Antoshkina, Burin Asavapibhop, Didier Auguste, Margherita Buizza Avanzini, Andrej Babic, Jingzhi Bai, Weidong Bai, Nikita Balashov, Roberto Barbera, Andrea Barresi , et al. (1114 additional authors not shown)

Abstract: The Jiangmen Underground Neutrino Observatory (JUNO) started physics data taking on 26 August 2025. JUNO consists of a 20-kton liquid scintillator central detector, surrounded by a 35 kton water pool serving as a Cherenkov veto, and almost 1000 m$^2$ of plastic scintillator veto on top. The detector is located in a shallow underground laboratory with an overburden of 1800 m.w.e. This paper present… ▽ More The Jiangmen Underground Neutrino Observatory (JUNO) started physics data taking on 26 August 2025. JUNO consists of a 20-kton liquid scintillator central detector, surrounded by a 35 kton water pool serving as a Cherenkov veto, and almost 1000 m$^2$ of plastic scintillator veto on top. The detector is located in a shallow underground laboratory with an overburden of 1800 m.w.e. This paper presents the performance results of the detector, extensively studied during the commissioning of the water phase, the subsequent liquid scintillator filling phase, and the first physics runs. The liquid scintillator achieved an attenuation length of 20.6 m at 430 nm, while the high coverage PMT system and scintillator together yielded about 1785 photoelectrons per MeV of energy deposit at the detector centre, measured using the 2.223 MeV $γ$ from neutron captures on hydrogen with an Am-C calibration source. The reconstructed energy resolution is 3.4% for two 0.511 MeV $γ$ at the detector centre and 2.9% for the 0.93 MeV quenched Po-214 alpha decays from natural radioactive sources. The energy nonlinearity is calibrated to better than 1%. Intrinsic contaminations of U-238 and Th-232 in the liquid scintillator are below 10$^{-16}$ g/g, assuming secular equilibrium. The water Cherenkov detector achieves a muon detection efficiency better than 99.9% for muons traversing the liquid scintillator volume. During the initial science runs, the data acquisition duty cycle exceeded 97.8%, demonstrating the excellent stability and readiness of JUNO for high-precision neutrino physics. △ Less

Submitted 18 November, 2025; originally announced November 2025.

Comments: 38 pages, 23 figures

Constraints on ultraheavy dark matter from the CDEX-10 experiment at the China Jinping Underground Laboratory

Authors: Y. F. Wang, L. T. Yang, Q. Yue, K. J. Kang, Y. J. Li, H. P. An, Greeshma C., J. P. Chang, H. Chen, Y. H. Chen, J. P. Cheng, J. Y. Cui, W. H. Dai, Z. Deng, Y. X. Dong, C. H. Fang, H. Gong, Q. J. Guo, T. Guo, X. Y. Guo, L. He, J. R. He, H. X. Huang, T. C. Huang, S. Karmakar , et al. (63 additional authors not shown)

Abstract: We report a search for ultraheavy dark matter (UHDM) with the CDEX-10 experiment at the China Jinping Underground Laboratory. Using a Monte Carlo framework that incorporates Earth shielding effects, we simulated UHDM propagation and energy deposition in p-type point-contact germanium detectors. Analysis of 205.4 kg$\cdot$day exposure in the 0.16--4.16 keVee range showed no excess above background.… ▽ More We report a search for ultraheavy dark matter (UHDM) with the CDEX-10 experiment at the China Jinping Underground Laboratory. Using a Monte Carlo framework that incorporates Earth shielding effects, we simulated UHDM propagation and energy deposition in p-type point-contact germanium detectors. Analysis of 205.4 kg$\cdot$day exposure in the 0.16--4.16 keVee range showed no excess above background. Our results exclude the spin-independent UHDM-nucleon scattering with two cross section scales, with the UHDM mass from $10^6$ to $10^{11}$ GeV, and provide the most stringent constraints with solid-state detectors below $10^8$ GeV. △ Less

Submitted 28 March, 2026; v1 submitted 24 October, 2025; originally announced October 2025.

Comments: 8 pages, 5 figures. Version updated to match PRD version

Journal ref: Phys. Rev. D 113, 052011 (2026)

Wide-Field Reflective Imaging with an Epi-Illumination Multi-Camera Array Microscope

Authors: Xiangjiang Bao, Lucas Kreiss, Clare B. Cook, Haoyu Gong, Mark Harfouche, Roarke Horstmeyer

Abstract: We present an epi-illumination multi-camera array microscope (epi-MCAM) designed for wide-field reflective imaging of non-transparent samples. The epi-MCAM contains 24 tightly packed and synchronized epi-illumination microscope units, arranged in a $4 \times 6$ planar array at 18 mm spacing. Each unit contains a unique CMOS image sensor (13 megapixels each), an objective and tube lens pair, and a… ▽ More We present an epi-illumination multi-camera array microscope (epi-MCAM) designed for wide-field reflective imaging of non-transparent samples. The epi-MCAM contains 24 tightly packed and synchronized epi-illumination microscope units, arranged in a $4 \times 6$ planar array at 18 mm spacing. Each unit contains a unique CMOS image sensor (13 megapixels each), an objective and tube lens pair, and a beamsplitter and epi-illumination light path. An epi-MCAM capture cycle produces a stitched image covering $72 \times 108~\mathrm{mm}^2$ at a micrometer scale resolution down to 2.46 $μ$m. To image samples exceeding this native field of view, we translate the entire array across the sample surface to enable high-resolution coverage of large objects. We demonstrate the system's ability to image both flat and three-dimensionally structured reflective samples, such as semiconductor wafers and printed circuit boards, which highlight the epi-MCAM's strong potential within industrial inspection applications. △ Less

Submitted 15 October, 2025; originally announced October 2025.

Comments: 13 pages, 5 figures

Constraints on inelastic dark matter from the CDEX-1B experiment

Authors: Y. F. Liang, L. T. Yang, Q. Yue, K. J. Kang, Y. J. Li, H. P. An, Greeshma C., J. P. Chang, H. Chen, Y. H. Chen, J. P. Cheng, J. Y. Cui, W. H. Dai, Z. Deng, Y. X. Dong, C. H. Fang, H. Gong, Q. J. Guo, T. Guo, X. Y. Guo, L. He, J. R. He, H. X. Huang, T. C. Huang, S. Karmakar , et al. (63 additional authors not shown)

Abstract: We present limits on spin-independent inelastic weakly interacting massive particles (WIMP)-nucleus scattering using the 737.1 kg$\cdot$day dataset from the CDEX-1B experiment. Expected nuclear recoil spectra for various inelastic WIMP masses $m_χ$ and mass splittings $δ$ are calculated under the standard halo model. An accurate background model of CDEX-1B is constructed by simulating all major ba… ▽ More We present limits on spin-independent inelastic weakly interacting massive particles (WIMP)-nucleus scattering using the 737.1 kg$\cdot$day dataset from the CDEX-1B experiment. Expected nuclear recoil spectra for various inelastic WIMP masses $m_χ$ and mass splittings $δ$ are calculated under the standard halo model. An accurate background model of CDEX-1B is constructed by simulating all major background sources. The model parameters are then determined through maximum likelihood estimation and Markov chain Monte Carlo fitting. The resulting 90\% confidence level upper limits on the WIMP-nucleon cross section $σ_{\mathrm{n}}$ exclude certain DAMA/LIBRA allowed regions: the $χ^2 < 4$ regions for $δ< 30$ keV at $m_χ= 250$ GeV and the $χ^2 < 9$ region for $δ< 50$ keV at $m_χ= 500$ GeV. The method is applicable to other inelastic dark matter scenarios, and the upcoming CDEX-50 experiment is expected to improve sensitivity by four orders of magnitude. △ Less

Submitted 31 December, 2025; v1 submitted 9 October, 2025; originally announced October 2025.

Comments: 10 pages, 8 figures. Version updated to match PRD version

Journal ref: Phys. Rev. D 112, 112025 (2025)

Design, waterproofing, and mass production of the 3-inch PMT frontend system of JUNO

Authors: Jilei Xu, Miao He, Cédric Cerna, Yongbo Huang, Thomas Adam, Shakeel Ahmad, Rizwan Ahmed, Fengpeng An, Costas Andreopoulos, Giuseppe Andronico, João Pedro Athayde Marcondes de André, Nikolay Anfimov, Vito Antonelli, Tatiana Antoshkina, Didier Auguste, Weidong Bai, Nikita Balashov, Andrea Barresi, Davide Basilico, Eric Baussan, Marco Beretta, Antonio Bergnoli, Nikita Bessonov, Daniel Bick, Lukas Bieger , et al. (609 additional authors not shown)

Abstract: Over 25,600 3-inch photomultiplier tubes (PMTs) have been instrumented for the central detector of the Jiangmen Underground Neutrino Observatory. Each PMT is equipped with a high-voltage divider and a frontend cable with waterproof sealing. Groups of sixteen PMTs are connected to the underwater frontend readout electronics via specialized multi-channel waterproof connectors. This paper outlines th… ▽ More Over 25,600 3-inch photomultiplier tubes (PMTs) have been instrumented for the central detector of the Jiangmen Underground Neutrino Observatory. Each PMT is equipped with a high-voltage divider and a frontend cable with waterproof sealing. Groups of sixteen PMTs are connected to the underwater frontend readout electronics via specialized multi-channel waterproof connectors. This paper outlines the design and mass production processes for the high-voltage divider, the cable and connector, as well as the waterproof potting of the PMT bases. The results of the acceptance tests of all the integrated PMTs are also presented. △ Less

Submitted 22 January, 2026; v1 submitted 7 October, 2025; originally announced October 2025.

Conceptual Design Report of Super Tau-Charm Facility: The Accelerator

Authors: Jiancong Bao, Anton Bogomyagkov, Zexin Cao, Mingxuan Chang, Fangzhou Chen, Guanghua Chen, Qi Chen, Qushan Chen, Zhi Chen, Kuanjun Fan, Hailiang Gong, Duan Gu, Hao Guo, Tengjun Guo, Chongchao He, Tianlong He, Kaiwen Hou, Hao Hu, Tongning Hu, Xiaocheng Hu, Dazhang Huang, Pengwei Huang, Ruixuan Huang, Zhicheng Huang, Hangzhou Li , et al. (71 additional authors not shown)

Abstract: Electron-positron colliders operating in the GeV region of center-of-mass energies or the Tau-Charm energy region, have been proven to enable competitive frontier research, due to its several unique features. With the progress of high energy physics in the last two decades, a new-generation Tau-Charm factory, Super Tau Charm Facility (STCF) has been actively promoting by the particle physics commu… ▽ More Electron-positron colliders operating in the GeV region of center-of-mass energies or the Tau-Charm energy region, have been proven to enable competitive frontier research, due to its several unique features. With the progress of high energy physics in the last two decades, a new-generation Tau-Charm factory, Super Tau Charm Facility (STCF) has been actively promoting by the particle physics community in China. STCF holds great potential to address fundamental questions such as the essence of color confinement and the matter-antimatter asymmetry in the universe in the next decades. The main design goals of STCF are with a center-of-mass energy ranging from 2 to 7 GeV and a peak luminosity surpassing 5*10^34 cm^-2s^-1 that is optimized at a center-of-mass energy of 4 GeV, which is about 50 times that of the currently operating Tau-Charm factory - BEPCII. The STCF accelerator is composed of two main parts: a double-ring collider with the crab-waist collision scheme and an injector that provides top-up injections for both electron and positron beams. As a typical third-generation electron-positron circular collider, the STCF accelerator faces many challenges in both accelerator physics and technology. In this paper, the conceptual design of the STCF accelerator complex is presented, including the ongoing efforts and plans for technological R&D, as well as the required infrastructure. The STCF project aims to secure support from the Chinese central government for its construction during the 15th Five-Year Plan (2026-2030) in China. △ Less

Submitted 16 September, 2025; v1 submitted 14 September, 2025; originally announced September 2025.

Comments: 296 pages

Constraints on dark matter boosted by supernova shock within the effective field theory framework from the CDEX-10 experiment

Authors: J. Z. Wang, L. T. Yang, Q. Yue, K. J. Kang, Y. J. Li, H. P. An, Greeshma C., J. P. Chang, H. Chen, Y. H. Chen, J. P. Cheng, W. H. Dai, Z. Deng, C. H. Fang, X. P. Geng, H. Gong, Q. J. Guo, T. Guo, X. Y. Guo, L. He, J. R. He, H. X. Huang, T. C. Huang, S. Karmakar, H. B. Li , et al. (62 additional authors not shown)

Abstract: Supernova shocks can boost dark matter (DM) particles to high, yet nonrelativistic, velocities, providing a suitable mechanism for analysis within the framework of the nonrelativistic effective field theory (NREFT). These accelerated DM sources extend the experimental ability to scan the parameter space of light DM into the sub-GeV region. In this study, we specifically analyze DM accelerated by t… ▽ More Supernova shocks can boost dark matter (DM) particles to high, yet nonrelativistic, velocities, providing a suitable mechanism for analysis within the framework of the nonrelativistic effective field theory (NREFT). These accelerated DM sources extend the experimental ability to scan the parameter space of light DM into the sub-GeV region. In this study, we specifically analyze DM accelerated by the Monogem Ring supernova remnant, whose age ($\sim 68000$ yr) and distance to Earth ($\sim 300$ parsec) are strategically matched to enable detection with current terrestrial detectors. Utilizing the 205.4 kg$\cdot$day data obtained from the CDEX-10 experiment at the China Jinping Underground Laboratory, we derive new constraints on boosted DM within the NREFT framework. The NREFT coupling constant exclusion regions now penetrate the sub-GeV mass range, with optimal sensitivity achieved for operators $\mathcal{O}_{3}$, $\mathcal{O}_{6}$, $\mathcal{O}_{15}$ in the 0.4--0.6 GeV mass range. △ Less

Submitted 18 November, 2025; v1 submitted 4 April, 2025; originally announced April 2025.

Comments: 9 pages, 5 figures. Version updated to match PRD version

Journal ref: Phys. Rev. D 112, 092011 (2025)

Simulation of the Background from $^{13}$C$(α, n)^{16}$O Reaction in the JUNO Scintillator

Authors: JUNO Collaboration, Thomas Adam, Kai Adamowicz, Shakeel Ahmad, Rizwan Ahmed, Sebastiano Aiello, Fengpeng An, Costas Andreopoulos, Giuseppe Andronico, Nikolay Anfimov, Vito Antonelli, Tatiana Antoshkina, João Pedro Athayde Marcondes de André, Didier Auguste, Weidong Bai, Nikita Balashov, Andrea Barresi, Davide Basilico, Eric Baussan, Marco Beretta, Antonio Bergnoli, Nikita Bessonov, Daniel Bick, Lukas Bieger, Svetlana Biktemerova , et al. (608 additional authors not shown)

Abstract: Large-scale organic liquid scintillator detectors are highly efficient in the detection of MeV-scale electron antineutrinos. These signal events can be detected through inverse beta decay on protons, which produce a positron accompanied by a neutron. A noteworthy background for antineutrinos coming from nuclear power reactors and from the depths of the Earth (geoneutrinos) is generated by ($α, n$)… ▽ More Large-scale organic liquid scintillator detectors are highly efficient in the detection of MeV-scale electron antineutrinos. These signal events can be detected through inverse beta decay on protons, which produce a positron accompanied by a neutron. A noteworthy background for antineutrinos coming from nuclear power reactors and from the depths of the Earth (geoneutrinos) is generated by ($α, n$) reactions. In organic liquid scintillator detectors, $α$ particles emitted from intrinsic contaminants such as $^{238}$U, $^{232}$Th, and $^{210}$Pb/$^{210}$Po, can be captured on $^{13}$C nuclei, followed by the emission of a MeV-scale neutron. Three distinct interaction mechanisms can produce prompt energy depositions preceding the delayed neutron capture, leading to a pair of events correlated in space and time within the detector. Thus, ($α, n$) reactions represent an indistinguishable background in liquid scintillator-based antineutrino detectors, where their expected rate and energy spectrum are typically evaluated via Monte Carlo simulations. This work presents results from the open-source SaG4n software, used to calculate the expected energy depositions from the neutron and any associated de-excitation products. Also simulated is a detailed detector response to these interactions, using a dedicated Geant4-based simulation software from the JUNO experiment. An expected measurable $^{13}$C$(α, n)^{16}$O event rate and reconstructed prompt energy spectrum with associated uncertainties, are presented in the context of JUNO, however, the methods and results are applicable and relevant to other organic liquid scintillator neutrino detectors. △ Less

Submitted 2 May, 2025; v1 submitted 2 March, 2025; originally announced March 2025.

Comments: 25 pages, 14 figures, 4 tables

Prediction of Energy Resolution in the JUNO Experiment

Authors: JUNO Collaboration, Angel Abusleme, Thomas Adam, Kai Adamowicz, Shakeel Ahmad, Rizwan Ahmed, Sebastiano Aiello, Fengpeng An, Qi An, Giuseppe Andronico, Nikolay Anfimov, Vito Antonelli, Tatiana Antoshkina, João Pedro Athayde Marcondes de André, Didier Auguste, Weidong Bai, Nikita Balashov, Wander Baldini, Andrea Barresi, Davide Basilico, Eric Baussan, Marco Bellato, Marco Beretta, Antonio Bergnoli, Daniel Bick , et al. (629 additional authors not shown)

Abstract: This paper presents an energy resolution study of the JUNO experiment, incorporating the latest knowledge acquired during the detector construction phase. The determination of neutrino mass ordering in JUNO requires an exceptional energy resolution better than 3\% at 1~MeV. To achieve this ambitious goal, significant efforts have been undertaken in the design and production of the key components o… ▽ More This paper presents an energy resolution study of the JUNO experiment, incorporating the latest knowledge acquired during the detector construction phase. The determination of neutrino mass ordering in JUNO requires an exceptional energy resolution better than 3\% at 1~MeV. To achieve this ambitious goal, significant efforts have been undertaken in the design and production of the key components of the JUNO detector. Various factors affecting the detection of inverse beta decay signals have an impact on the energy resolution, extending beyond the statistical fluctuations of the detected number of photons, such as the properties of the liquid scintillator, performance of photomultiplier tubes, and the energy reconstruction algorithm. To account for these effects, a full JUNO simulation and reconstruction approach is employed. This enables the modeling of all relevant effects and the evaluation of associated inputs to accurately estimate the energy resolution. The results of study reveal an energy resolution of 2.95\% at 1~MeV. Furthermore, this study assesses the contribution of major effects to the overall energy resolution budget. This analysis serves as a reference for interpreting future measurements of energy resolution during JUNO data collection. Moreover, it provides a guideline for comprehending the energy resolution characteristics of liquid scintillator-based detectors. △ Less

Submitted 9 January, 2025; v1 submitted 28 May, 2024; originally announced May 2024.

Journal ref: Chinese Phys. C 49 013003 (2025)

Data quality control system and long-term performance monitor of the LHAASO-KM2A

Authors: Zhen Cao, F. Aharonian, Axikegu, Y. X. Bai, Y. W. Bao, D. Bastieri, X. J. Bi, Y. J. Bi, W. Bian, A. V. Bukevich, Q. Cao, W. Y. Cao, Zhe Cao, J. Chang, J. F. Chang, A. M. Chen, E. S. Chen, H. X. Chen, Liang Chen, Lin Chen, Long Chen, M. J. Chen, M. L. Chen, Q. H. Chen, S. Chen , et al. (263 additional authors not shown)

Abstract: The KM2A is the largest sub-array of the Large High Altitude Air Shower Observatory (LHAASO). It consists of 5216 electromagnetic particle detectors (EDs) and 1188 muon detectors (MDs). The data recorded by the EDs and MDs are used to reconstruct primary information of cosmic ray and gamma-ray showers. This information is used for physical analysis in gamma-ray astronomy and cosmic ray physics. To… ▽ More The KM2A is the largest sub-array of the Large High Altitude Air Shower Observatory (LHAASO). It consists of 5216 electromagnetic particle detectors (EDs) and 1188 muon detectors (MDs). The data recorded by the EDs and MDs are used to reconstruct primary information of cosmic ray and gamma-ray showers. This information is used for physical analysis in gamma-ray astronomy and cosmic ray physics. To ensure the reliability of the LHAASO-KM2A data, a three-level quality control system has been established. It is used to monitor the status of detector units, stability of reconstructed parameters and the performance of the array based on observations of the Crab Nebula and Moon shadow. This paper will introduce the control system and its application on the LHAASO-KM2A data collected from August 2021 to July 2023. During this period, the pointing and angular resolution of the array were stable. From the observations of the Moon shadow and Crab Nebula, the results achieved using the two methods are consistent with each other. According to the observation of the Crab Nebula at energies from 25 TeV to 100 TeV, the time averaged pointing errors are estimated to be $-0.003^{\circ} \pm 0.005^{\circ}$ and $0.001^{\circ} \pm 0.006^{\circ}$ in the R.A. and Dec directions, respectively. △ Less

Submitted 13 June, 2024; v1 submitted 20 May, 2024; originally announced May 2024.

Comments: 15 pages, 9 figures

Search for solar axions by Primakoff effect with the full dataset of the CDEX-1B Experiment

Authors: L. T. Yang, S. K. Liu, Q. Yue, K. J. Kang, Y. J. Li, H. P. An, Greeshma C., J. P. Chang, Y. H. Chen, J. P. Cheng, W. H. Dai, Z. Deng, C. H. Fang, X. P. Geng, H. Gong, Q. J. Guo, T. Guo, X. Y. Guo, L. He, J. R. He, J. W. Hu, H. X. Huang, T. C. Huang, L. Jiang, S. Karmakar , et al. (61 additional authors not shown)

Abstract: We present the first limit on $g_{Aγ}$ coupling constant using the Bragg-Primakoff conversion based on an exposure of 1107.5 kg days of data from the CDEX-1B experiment at the China Jinping Underground Laboratory. The data are consistent with the null signal hypothesis, and no excess signals are observed. Limits of the coupling $g_{Aγ}<2.08\times10^{-9}$ GeV$^{-1}$ (95\% C.L.) are derived for axio… ▽ More We present the first limit on $g_{Aγ}$ coupling constant using the Bragg-Primakoff conversion based on an exposure of 1107.5 kg days of data from the CDEX-1B experiment at the China Jinping Underground Laboratory. The data are consistent with the null signal hypothesis, and no excess signals are observed. Limits of the coupling $g_{Aγ}<2.08\times10^{-9}$ GeV$^{-1}$ (95\% C.L.) are derived for axions with mass up to 100 eV/$c^2$. Within the hadronic model of KSVZ, our results exclude axion mass $>5.3~\rm{eV}/c^2$ at 95\% C.L. △ Less

Submitted 12 May, 2024; originally announced May 2024.

Comments: 7 pages, 5 figures

First search for light fermionic dark matter absorption on electrons using germanium detector in CDEX-10 experiment

Authors: J. X. Liu, L. T. Yang, Q. Yue, K. J. Kang, Y. J. Li, H. P. An, Greeshma C., J. P. Chang, Y. H. Chen, J. P. Cheng, W. H. Dai, Z. Deng, C. H. Fang, X. P. Geng, H. Gong, Q. J. Guo, T. Guo, X. Y. Guo, L. He, J. R. He, J. W. Hu, H. X. Huang, T. C. Huang, L. Jiang, S. Karmakar , et al. (61 additional authors not shown)

Abstract: We present the first results of the search for sub-MeV fermionic dark matter absorbed by electron targets of germanium using the 205.4~kg$\cdot$day data collected by the CDEX-10 experiment, with the analysis threshold of 160~eVee. No significant dark matter (DM) signals over the background are observed. Results are presented as limits on the cross section of DM--electron interaction. We present ne… ▽ More We present the first results of the search for sub-MeV fermionic dark matter absorbed by electron targets of germanium using the 205.4~kg$\cdot$day data collected by the CDEX-10 experiment, with the analysis threshold of 160~eVee. No significant dark matter (DM) signals over the background are observed. Results are presented as limits on the cross section of DM--electron interaction. We present new constraints of cross section in the DM range of 0.1--10 keV/$c^2$ for vector and axial-vector interaction. The upper limit on the cross section is set to be $\rm 6.8\times10^{-46}~cm^2$ for vector interaction, and $\rm 2.3\times10^{-46}~cm^2$ for axial-vector interaction at DM mass of 5 keV/$c^2$. △ Less

Submitted 17 February, 2026; v1 submitted 15 April, 2024; originally announced April 2024.

Comments: 6 pages, 4 figures. Version updated to match PRD version

Journal ref: Phys. Rev. D 113, 032011 (2026)

Constraints on the Blazar-Boosted Dark Matter from the CDEX-10 Experiment

Authors: R. Xu, L. T. Yang, Q. Yue, K. J. Kang, Y. J. Li, H. P. An, Greeshma C., J. P. Chang, Y. H. Chen, J. P. Cheng, W. H. Dai, Z. Deng, C. H. Fang, X. P. Geng, H. Gong, Q. J. Guo, T. Guo, X. Y. Guo, L. He, S. M. He, J. W. Hu, H. X. Huang, T. C. Huang, L. Jiang, S. Karmakar , et al. (59 additional authors not shown)

Abstract: We report new constraints on light dark matter (DM) boosted by blazars using the 205.4 kg day data from the CDEX-10 experiment located at the China Jinping Underground Laboratory. Two representative blazars, TXS 0506+56 and BL Lacertae are studied. The results derived from TXS 0506+56 exclude DM-nucleon elastic scattering cross sections from $4.6\times 10^{-33}\ \rm cm^2$ to… ▽ More We report new constraints on light dark matter (DM) boosted by blazars using the 205.4 kg day data from the CDEX-10 experiment located at the China Jinping Underground Laboratory. Two representative blazars, TXS 0506+56 and BL Lacertae are studied. The results derived from TXS 0506+56 exclude DM-nucleon elastic scattering cross sections from $4.6\times 10^{-33}\ \rm cm^2$ to $1\times10^{-26}\ \rm cm^2$ for DM masses between 10 keV and 1 GeV, and the results derived from BL Lacertae exclude DM-nucleon elastic scattering cross sections from $2.4\times 10^{-34}\ \rm cm^2$ to $1\times10^{-26}\ \rm cm^2$ for the same range of DM masses. The constraints correspond to the best sensitivities among solid-state detector experiments in the sub-MeV mass range. △ Less

Submitted 29 March, 2024; originally announced March 2024.

Comments: 7 pages, 4 figures

Probing Dark Matter Particles from Evaporating Primordial Black Holes via Electron Scattering in the CDEX-10 Experiment

Authors: Z. H. Zhang, L. T. Yang, Q. Yue, K. J. Kang, Y. J. Li, H. P. An, Greeshma C., J. P. Chang, Y. H. Chen, J. P. Cheng, W. H. Dai, Z. Deng, C. H. Fang, X. P. Geng, H. Gong, Q. J. Guo, T. Guo, X. Y. Guo, L. He, S. M. He, J. W. Hu, H. X. Huang, T. C. Huang, L. Jiang, S. Karmakar , et al. (59 additional authors not shown)

Abstract: Dark matter (DM) is a major constituent of the Universe. However, no definite evidence of DM particles (denoted as ``$χ$") has been found in DM direct detection (DD) experiments to date. There is a novel concept of detecting $χ$ from evaporating primordial black holes (PBHs). We search for $χ$ emitted from PBHs by investigating their interaction with target electrons. The examined PBH masses range… ▽ More Dark matter (DM) is a major constituent of the Universe. However, no definite evidence of DM particles (denoted as ``$χ$") has been found in DM direct detection (DD) experiments to date. There is a novel concept of detecting $χ$ from evaporating primordial black holes (PBHs). We search for $χ$ emitted from PBHs by investigating their interaction with target electrons. The examined PBH masses range from 1$\times$10$^{15}$ to 7$\times$10$^{16}$ g under the current limits of PBH abundance $f_{PBH}$. Using 205.4 kg$\cdot$day data obtained from the CDEX-10 experiment conducted in the China Jinping Underground Laboratory, we exclude the $χ$--electron ($χ$--$e$) elastic-scattering cross section $σ_{χe} \sim 5\times10^{-29}$ cm$^2$ for $χ$ with a mass $m_χ\lesssim$ 0.1 keV from our results. With the higher radiation background but lower energy threshold (160 eV), CDEX-10 fill a part of the gap in the previous work. If ($m_χ$, $σ_{χe}$) can be determined in the future, DD experiments are expected to impose strong constraints on $f_{PBH}$ for large $M_{PBH}$s. △ Less

Submitted 22 September, 2024; v1 submitted 29 March, 2024; originally announced March 2024.

Comments: 9 pages, 6 figures, 3 tables. Version updated to match SCPMA version

Journal ref: Sci. China Phys. Mech. Astron. 67, 101011 (2024)

Experimental Limits on Solar Reflected Dark Matter with a New Approach on Accelerated-Dark-Matter-Electron Analysis in Semiconductors

Authors: Z. Y. Zhang, L. T. Yang, Q. Yue, K. J. Kang, Y. J. Li, H. P. An, Greeshma C., J. P. Chang, Y. H. Chen, J. P. Cheng, W. H. Dai, Z. Deng, C. H. Fang, X. P. Geng, H. Gong, Q. J. Guo, T. Guo, X. Y. Guo, L. He, S. M. He, J. W. Hu, H. X. Huang, T. C. Huang, L. Jiang, S. Karmakar , et al. (59 additional authors not shown)

Abstract: Recently a dark matter-electron (DM-electron) paradigm has drawn much attention. Models beyond the standard halo model describing DM accelerated by high energy celestial bodies are under intense examination as well. In this Letter, a velocity components analysis (VCA) method dedicated to swift analysis of accelerated DM-electron interactions via semiconductor detectors is proposed and the first HP… ▽ More Recently a dark matter-electron (DM-electron) paradigm has drawn much attention. Models beyond the standard halo model describing DM accelerated by high energy celestial bodies are under intense examination as well. In this Letter, a velocity components analysis (VCA) method dedicated to swift analysis of accelerated DM-electron interactions via semiconductor detectors is proposed and the first HPGe detector-based accelerated DM-electron analysis is realized. Utilizing the method, the first germanium based constraint on sub-GeV solar reflected DM-electron interaction is presented with the 205.4 kg$\cdot$day dataset from the CDEX-10 experiment. In the heavy mediator scenario, our result excels in the mass range of 5$-$15 keV/$c^2$, achieving a 3 orders of magnitude improvement comparing with previous semiconductor experiments. In the light mediator scenario, the strongest laboratory constraint for DM lighter than 0.1 MeV/$c^2$ is presented. The result proves the feasibility and demonstrates the vast potential of the VCA technique in future accelerated DM-electron analyses with semiconductor detectors. △ Less

Submitted 24 April, 2024; v1 submitted 26 September, 2023; originally announced September 2023.

Comments: 7 pages, 4 figures. Version updated to match PRL version

Journal ref: Phys. Rev. Lett. 132, 171001 (2024)

Projected WIMP sensitivity of the CDEX-50 dark matter experiment

Authors: X. P. Geng, L. T. Yang, Q. Yue, K. J. Kang, Y. J. Li, H. P. An, Greeshma C., J. P. Chang, Y. H. Chen, J. P. Cheng, W. H. Dai, Z. Deng, C. H. Fang, H. Gong, Q. J. Guo, T. Guo, X. Y. Guo, L. He, S. M. He, J. W. Hu, H. X. Huang, T. C. Huang, L. Jiang, S. Karmakar, H. B. Li , et al. (59 additional authors not shown)

Abstract: CDEX-50 is a next-generation project of the China Dark Matter Experiment (CDEX) that aims to search for dark matter using a 50-kg germanium detector array. This paper comprises a thorough summary of the CDEX-50 dark matter experiment, including an investigation of potential background sources and the development of a background model. Based on the baseline model, the projected sensitivity of weakl… ▽ More CDEX-50 is a next-generation project of the China Dark Matter Experiment (CDEX) that aims to search for dark matter using a 50-kg germanium detector array. This paper comprises a thorough summary of the CDEX-50 dark matter experiment, including an investigation of potential background sources and the development of a background model. Based on the baseline model, the projected sensitivity of weakly interacting massive particle (WIMP) is also presented. The expected background level within the energy region of interest, set to 2--2.5 keVee, is $\sim$0.01 counts keVee$^{-1}$ kg$^{-1}$ day$^{-1}$. At 90\% confidence level, the expected sensitivity to spin-independent WIMP-nucleon couplings is estimated to reach a cross-section of 5.1 $\times$ 10$^{-45}$ cm$^{2}$ for a WIMP mass of 5 GeV/c$^{2}$ with an exposure objective of 150 kg$\cdot$year and an analysis threshold of 160 eVee. This science goal will correspond to the most sensitive results for WIMPs with a mass of 2.2--8 GeV/c$^{2}$. △ Less

Submitted 4 July, 2024; v1 submitted 4 September, 2023; originally announced September 2023.

Comments: 12 pages, 11 figures. Version updated to match JCAP version

Journal ref: JCAP 07 (2024) 009

Searching for $^{76}$Ge neutrinoless double beta decay with the CDEX-1B experiment

Authors: B. T. Zhang, J. Z. Wang, L. T. Yang, Q. Yue, K. J. Kang, Y. J. Li, H. P. An, Greeshma C., J. P. Chang, Y. H. Chen, J. P. Cheng, W. H. Dai, Z. Deng, C. H. Fang, X. P. Geng, H. Gong, Q. J. Guo, X. Y. Guo, L. He, S. M. He, J. W. Hu, H. X. Huang, T. C. Huang, H. T. Jia, X. Jiang , et al. (60 additional authors not shown)

Abstract: We operated a p-type point contact high purity germanium (PPCGe) detector (CDEX-1B, 1.008 kg) in the China Jinping Underground Laboratory (CJPL) for 500.3 days to search for neutrinoless double beta ($0νββ$) decay of $^{76}$Ge. A total of 504.3 kg$\cdot$day effective exposure data was accumulated. The anti-coincidence and the multi/single-site event (MSE/SSE) discrimination methods were used to su… ▽ More We operated a p-type point contact high purity germanium (PPCGe) detector (CDEX-1B, 1.008 kg) in the China Jinping Underground Laboratory (CJPL) for 500.3 days to search for neutrinoless double beta ($0νββ$) decay of $^{76}$Ge. A total of 504.3 kg$\cdot$day effective exposure data was accumulated. The anti-coincidence and the multi/single-site event (MSE/SSE) discrimination methods were used to suppress the background in the energy region of interest (ROI, 1989$-$2089 keV for this work) with a factor of 23. A background level of 0.33 counts/(keV$\cdot$kg$\cdot$yr) was realized. The lower limit on the half life of $^{76}$Ge $0νββ$ decay was constrained as $T_{1/2}^{0ν}\ > \ {1.0}\times 10^{23}\ \rm yr\ (90\% \ C.L.)$, corresponding to the upper limits on the effective Majorana neutrino mass: $\langle m_{ββ}\rangle < $3.2$-$7.5$\ \mathrm{eV}$. △ Less

Submitted 22 September, 2024; v1 submitted 1 May, 2023; originally announced May 2023.

Comments: 11 pages, 12 figures, 2 tables. Version updated to match CPC version

Journal ref: Chin. Phys. C 48, 101001 (2024)

On the uncertainty analysis of the data-enabled physics-informed neural network for solving neutron diffusion eigenvalue problem

Authors: Yu Yang, Helin Gong, Qihong Yang, Yangtao Deng, Qiaolin He, Shiquan Zhang

Abstract: In practical engineering experiments, the data obtained through detectors are inevitably noisy. For the already proposed data-enabled physics-informed neural network (DEPINN) \citep{DEPINN}, we investigate the performance of DEPINN in calculating the neutron diffusion eigenvalue problem from several perspectives when the prior data contain different scales of noise. Further, in order to reduce the… ▽ More In practical engineering experiments, the data obtained through detectors are inevitably noisy. For the already proposed data-enabled physics-informed neural network (DEPINN) \citep{DEPINN}, we investigate the performance of DEPINN in calculating the neutron diffusion eigenvalue problem from several perspectives when the prior data contain different scales of noise. Further, in order to reduce the effect of noise and improve the utilization of the noisy prior data, we propose innovative interval loss functions and give some rigorous mathematical proofs. The robustness of DEPINN is examined on two typical benchmark problems through a large number of numerical results, and the effectiveness of the proposed interval loss function is demonstrated by comparison. This paper confirms the feasibility of the improved DEPINN for practical engineering applications in nuclear reactor physics. △ Less

Submitted 17 March, 2023; v1 submitted 15 March, 2023; originally announced March 2023.

Comments: The experiments in Figures 6 and 10 in the article have errors that need to be corrected. Moreover, we intend to make massive changes to the content of the article, and therefore need to withdraw the article

The JUNO experiment Top Tracker

Authors: JUNO Collaboration, Angel Abusleme, Thomas Adam, Shakeel Ahmad, Rizwan Ahmed, Sebastiano Aiello, Muhammad Akram, Abid Aleem, Tsagkarakis Alexandros, Fengpeng An, Qi An, Giuseppe Andronico, Nikolay Anfimov, Vito Antonelli, Tatiana Antoshkina, Burin Asavapibhop, João Pedro Athayde Marcondes de André, Didier Auguste, Weidong Bai, Nikita Balashov, Wander Baldini, Andrea Barresi, Davide Basilico, Eric Baussan, Marco Bellato , et al. (592 additional authors not shown)

Abstract: The main task of the Top Tracker detector of the neutrino reactor experiment Jiangmen Underground Neutrino Observatory (JUNO) is to reconstruct and extrapolate atmospheric muon tracks down to the central detector. This muon tracker will help to evaluate the contribution of the cosmogenic background to the signal. The Top Tracker is located above JUNO's water Cherenkov Detector and Central Detector… ▽ More The main task of the Top Tracker detector of the neutrino reactor experiment Jiangmen Underground Neutrino Observatory (JUNO) is to reconstruct and extrapolate atmospheric muon tracks down to the central detector. This muon tracker will help to evaluate the contribution of the cosmogenic background to the signal. The Top Tracker is located above JUNO's water Cherenkov Detector and Central Detector, covering about 60% of the surface above them. The JUNO Top Tracker is constituted by the decommissioned OPERA experiment Target Tracker modules. The technology used consists in walls of two planes of plastic scintillator strips, one per transverse direction. Wavelength shifting fibres collect the light signal emitted by the scintillator strips and guide it to both ends where it is read by multianode photomultiplier tubes. Compared to the OPERA Target Tracker, the JUNO Top Tracker uses new electronics able to cope with the high rate produced by the high rock radioactivity compared to the one in Gran Sasso underground laboratory. This paper will present the new electronics and mechanical structure developed for the Top Tracker of JUNO along with its expected performance based on the current detector simulation. △ Less

Submitted 9 March, 2023; originally announced March 2023.

Comments: 20 pages

Journal ref: Nucl.Instrum.Meth.A 1057 (2023) 168680

JUNO sensitivity to $^7$Be, $pep$, and CNO solar neutrinos

Authors: Angel Abusleme, Thomas Adam, Shakeel Ahmad, Rizwan Ahmed, Sebastiano Aiello, Muhammad Akram, Abid Aleem, Tsagkarakis Alexandros, Fengpeng An, Qi An, Giuseppe Andronico, Nikolay Anfimov, Vito Antonelli, Tatiana Antoshkina, Burin Asavapibhop, João Pedro Athayde Marcondes de André, Didier Auguste, Weidong Bai, Nikita Balashov, Wander Baldini, Andrea Barresi, Davide Basilico, Eric Baussan, Marco Bellato, Marco Beretta , et al. (592 additional authors not shown)

Abstract: The Jiangmen Underground Neutrino Observatory (JUNO), the first multi-kton liquid scintillator detector, which is under construction in China, will have a unique potential to perform a real-time measurement of solar neutrinos well below the few MeV threshold typical for Water Cherenkov detectors. JUNO's large target mass and excellent energy resolution are prerequisites for reaching unprecedented… ▽ More The Jiangmen Underground Neutrino Observatory (JUNO), the first multi-kton liquid scintillator detector, which is under construction in China, will have a unique potential to perform a real-time measurement of solar neutrinos well below the few MeV threshold typical for Water Cherenkov detectors. JUNO's large target mass and excellent energy resolution are prerequisites for reaching unprecedented levels of precision. In this paper, we provide estimation of the JUNO sensitivity to 7Be, pep, and CNO solar neutrinos that can be obtained via a spectral analysis above the 0.45 MeV threshold. This study is performed assuming different scenarios of the liquid scintillator radiopurity, ranging from the most opti mistic one corresponding to the radiopurity levels obtained by the Borexino experiment, up to the minimum requirements needed to perform the neutrino mass ordering determination with reactor antineutrinos - the main goal of JUNO. Our study shows that in most scenarios, JUNO will be able to improve the current best measurements on 7Be, pep, and CNO solar neutrino fluxes. We also perform a study on the JUNO capability to detect periodical time variations in the solar neutrino flux, such as the day-night modulation induced by neutrino flavor regeneration in Earth, and the modulations induced by temperature changes driven by helioseismic waves. △ Less

Submitted 7 March, 2023; originally announced March 2023.

Design of the Readout Electronics for the TRIDENT Pathfinder Experiment

Authors: M. X. Wang, G. H. Gong, P. Miao, Z. Y. Sun, J. N. Tang, W. H. Wu, D. L. Xu

Abstract: The tRopIcal DEep-sea Neutrino Telescope (TRIDENT) is a future large-scale next-generation neutrino telescope. In September 2021, the TRIDENT pathfinder experiment (TRIDENT EXplorer, T-REX for short) completed in-situ measurements of deep-sea water properties in the South China Sea. The T-REX apparatus integrates two independent and complementary systems, a photomultiplier tube (PMT) and a camera… ▽ More The tRopIcal DEep-sea Neutrino Telescope (TRIDENT) is a future large-scale next-generation neutrino telescope. In September 2021, the TRIDENT pathfinder experiment (TRIDENT EXplorer, T-REX for short) completed in-situ measurements of deep-sea water properties in the South China Sea. The T-REX apparatus integrates two independent and complementary systems, a photomultiplier tube (PMT) and a camera system, to measure the optical and radioactive properties of the deep-sea water. One light emitter module and two light receiver modules were deployed, which were synchronized by using White Rabbit (WR) technology. The light emitter module generates nanosecond-width LED pulses, while the light receiver module hosts three PMTs and a camera to detect photons. The submerged apparatus and the data acquisition system (DAQ) perform real-time command and data transmission. We report the design and performance of the readout electronics for T-REX, including hardware modules, firmware design for digital signal processing, and host-computer software. △ Less

Submitted 6 March, 2023; originally announced March 2023.

Search for boosted keV-MeV light dark matter particles from evaporating primordial black holes at the CDEX-10 experiment

Authors: Z. H. Zhang, L. T. Yang, Q. Yue, K. J. Kang, Y. J. Li, H. P. An, Greeshma C., J. P. Chang, Y. H. Chen, J. P. Cheng, W. H. Dai, Z. Deng, C. H. Fang, X. P. Geng, H. Gong, Q. J. Guo, X. Y. Guo, L. He, S. M. He, J. W. Hu, H. X. Huang, T. C. Huang, H. T. Jia, X. Jiang, S. Karmakar , et al. (59 additional authors not shown)

Abstract: We present novel constraints on boosted light dark matter particles (denoted as ``$χ$'') from evaporating primordial black holes (PBHs) using 205.4 kg$\cdot$day data from the China Jinping Underground Laboratory's CDEX-10 p-type point contact germanium detector with a 160 eVee analysis threshold. $χ$ from PBHs with masses ranging from 1$\times$10$^{15}$ g to 7$\times$10$^{16}$ g are searched in th… ▽ More We present novel constraints on boosted light dark matter particles (denoted as ``$χ$'') from evaporating primordial black holes (PBHs) using 205.4 kg$\cdot$day data from the China Jinping Underground Laboratory's CDEX-10 p-type point contact germanium detector with a 160 eVee analysis threshold. $χ$ from PBHs with masses ranging from 1$\times$10$^{15}$ g to 7$\times$10$^{16}$ g are searched in this work. In the presence of PBH abundance compatible with present bounds, our result excludes the $χ$-nucleon elastic-scattering cross section region from 3.4$\times$10$^{-32}$ cm$^{2}$ to 2.3$\times$10$^{-29}$ cm$^{2}$ for $χ$ of 1 keV to 24 MeV from PBHs with masses of 5$\times$10$^{15}$ g, as well as from 1.1$\times$10$^{-28}$ cm$^{2}$ to 7.6$\times$10$^{-28}$ cm$^{2}$ for $χ$ of 1 keV to 0.6 MeV from PBHs with masses of 7$\times$10$^{16}$ g. If the $χ$-nucleon elastic-scattering cross section can be determined in the future, the abundance of PBHs may be severely constrained by $χ$ evaporation. With the lower threshold (160 eVee) of the CDEX-10 experiment compared to the previously used experiments, this work allows for a better reach at soft spectra produced by heavier PBHs, which demonstrates the vast potential of such a technical route to pursue $χ$ from larger PBHs with a low threshold. △ Less

Submitted 7 September, 2023; v1 submitted 14 November, 2022; originally announced November 2022.

Comments: 8 pages, 6 figures. Version updated to match PRD version

Journal ref: Phys. Rev. D 109, 052006 (2023)

Search for exotic interactions of solar neutrinos in the CDEX-10 experiment

Authors: X. P. Geng, L. T. Yang, Q. Yue, K. J. Kang, Y. J. Li, H. P. An, Greeshma C., J. P. Chang, Y. H. Chen, J. P. Cheng, W. H. Dai, Z. Deng, C. H. Fang, H. Gong, Q. J. Guo, X. Y. Guo, L. He, S. M. He, J. W. Hu, H. X. Huang, T. C. Huang, H. T. Jia, X. Jiang, S. Karmakar, H. B. Li , et al. (60 additional authors not shown)

Abstract: We investigate exotic neutrino interactions using the 205.4 kg$\cdot$day dataset from the CDEX-10 experiment at the China Jinping Underground Laboratory. New constraints on the mass and couplings of new gauge bosons are presented. Two nonstandard neutrino interactions are considered: a $U(1)_{B-L}$ gauge-boson-induced interaction between an active neutrino and electron/nucleus, and a dark-photon-i… ▽ More We investigate exotic neutrino interactions using the 205.4 kg$\cdot$day dataset from the CDEX-10 experiment at the China Jinping Underground Laboratory. New constraints on the mass and couplings of new gauge bosons are presented. Two nonstandard neutrino interactions are considered: a $U(1)_{B-L}$ gauge-boson-induced interaction between an active neutrino and electron/nucleus, and a dark-photon-induced interaction between a sterile neutrino and electron/nucleus via kinetic mixing with a photon. This work probes an unexplored parameter space involving sterile neutrino coupling with a dark photon. New laboratory limits are derived on dark photon masses below $1~{\rm eV}/c^{2}$ at some benchmark values of $Δm_{41}^{2}$ and $g^{\prime2}{\rm{sin}}^{2}2θ_{14}$. △ Less

Submitted 2 June, 2023; v1 submitted 4 October, 2022; originally announced October 2022.

Comments: 6 pages, 4 figures. Version updated to match PRD version

Journal ref: Phys. Rev. D 107, 112002 (2023)

PulseDL-II: A System-on-Chip Neural Network Accelerator for Timing and Energy Extraction of Nuclear Detector Signals

Authors: Pengcheng Ai, Zhi Deng, Yi Wang, Hui Gong, Xinchi Ran, Zijian Lang

Abstract: Front-end electronics equipped with high-speed digitizers are being used and proposed for future nuclear detectors. Recent literature reveals that deep learning models, especially one-dimensional convolutional neural networks, are promising when dealing with digital signals from nuclear detectors. Simulations and experiments demonstrate the satisfactory accuracy and additional benefits of neural n… ▽ More Front-end electronics equipped with high-speed digitizers are being used and proposed for future nuclear detectors. Recent literature reveals that deep learning models, especially one-dimensional convolutional neural networks, are promising when dealing with digital signals from nuclear detectors. Simulations and experiments demonstrate the satisfactory accuracy and additional benefits of neural networks in this area. However, specific hardware accelerating such models for online operations still needs to be studied. In this work, we introduce PulseDL-II, a system-on-chip (SoC) specially designed for applications of event feature (time, energy, etc.) extraction from pulses with deep learning. Based on the previous version, PulseDL-II incorporates a RISC CPU into the system structure for better functional flexibility and integrity. The neural network accelerator in the SoC adopts a three-level (arithmetic unit, processing element, neural network) hierarchical architecture and facilitates parameter optimization of the digital design. Furthermore, we devise a quantization scheme compatible with deep learning frameworks (e.g., TensorFlow) within a selected subset of layer types. We validate the correct operations of PulseDL-II on field programmable gate arrays (FPGA) alone and with an experimental setup comprising a direct digital synthesis (DDS) and analog-to-digital converters (ADC). The proposed system achieved 60 ps time resolution and 0.40% energy resolution at signal to noise ratio (SNR) of 47.4 dB. △ Less

Submitted 8 February, 2023; v1 submitted 2 September, 2022; originally announced September 2022.

Comments: Accepted by IEEE Transactions on Nuclear Science

A data-enabled physics-informed neural network with comprehensive numerical study on solving neutron diffusion eigenvalue problems

Authors: Yu Yang, Helin Gong, Shiquan Zhang, Qihong Yang, Zhang Chen, Qiaolin He, Qing Li

Abstract: We present a data-enabled physics-informed neural network (DEPINN) with comprehensive numerical study for solving industrial scale neutron diffusion eigenvalue problems (NDEPs). In order to achieve an engineering acceptable accuracy for complex engineering problems, a very small amount of prior data from physical experiments are suggested to be used, to improve the accuracy and efficiency of train… ▽ More We present a data-enabled physics-informed neural network (DEPINN) with comprehensive numerical study for solving industrial scale neutron diffusion eigenvalue problems (NDEPs). In order to achieve an engineering acceptable accuracy for complex engineering problems, a very small amount of prior data from physical experiments are suggested to be used, to improve the accuracy and efficiency of training. We design an adaptive optimization procedure with Adam and LBFGS to accelerate the convergence in the training stage. We discuss the effect of different physical parameters, sampling techniques, loss function allocation and the generalization performance of the proposed DEPINN model for solving complex problem. The feasibility of proposed DEPINN model is tested on three typical benchmark problems, from simple geometry to complex geometry, and from mono-energetic equation to two-group equations. Numerous numerical results show that DEPINN can efficiently solve NDEPs with an appropriate optimization procedure. The proposed DEPINN can be generalized for other input parameter settings once its structure been trained. This work confirms the possibility of DEPINN for practical engineering applications in nuclear reactor physics. △ Less

Submitted 13 November, 2022; v1 submitted 29 August, 2022; originally announced August 2022.

Constraints on Sub-GeV Dark Matter--Electron Scattering from the CDEX-10 Experiment

Authors: Z. Y. Zhang, L. T. Yang, Q. Yue, K. J. Kang, Y. J. Li, M. Agartioglu, H. P. An, J. P. Chang, Y. H. Chen, J. P. Cheng, W. H. Dai, Z. Deng, C. H. Fang, X. P. Geng, H. Gong, Q. J. Guo, X. Y. Guo, L. He, S. M. He, J. W. Hu, H. X. Huang, T. C. Huang, H. T. Jia, X. Jiang, H. B. Li , et al. (60 additional authors not shown)

Abstract: We present improved germanium-based constraints on sub-GeV dark matter via dark matter--electron ($χ$-$e$) scattering using the 205.4 kg$\cdot$day dataset from the CDEX-10 experiment. Using a novel calculation technique, we attain predicted $χ$-$e$ scattering spectra observable in high-purity germanium detectors. In the heavy mediator scenario, our results achieve 3 orders of magnitude of improvem… ▽ More We present improved germanium-based constraints on sub-GeV dark matter via dark matter--electron ($χ$-$e$) scattering using the 205.4 kg$\cdot$day dataset from the CDEX-10 experiment. Using a novel calculation technique, we attain predicted $χ$-$e$ scattering spectra observable in high-purity germanium detectors. In the heavy mediator scenario, our results achieve 3 orders of magnitude of improvement for $m_χ$ larger than 80 MeV/c$^2$ compared to previous germanium-based $χ$-$e$ results. We also present the most stringent $χ$-$e$ cross-section limit to date among experiments using solid-state detectors for $m_χ$ larger than 90 MeV/c$^2$ with heavy mediators and $m_χ$ larger than 100 MeV/c$^2$ with electric dipole coupling. The result proves the feasibility and demonstrates the vast potential of a new $χ$-$e$ detection method with high-purity germanium detectors in ultralow radioactive background. △ Less

Submitted 21 November, 2022; v1 submitted 8 June, 2022; originally announced June 2022.

Comments: 6 pages, 3 figures. Version updated to match PRL version

Journal ref: Phys. Rev. Lett. 129, 221301 (2022)

Performance of TPC detector prototype integrated with UV laser tracks for the circular collider

Authors: Z. Y. Yuan, H. R. Qi, Y. Chang, L. W. Yu, Y. M. Cai, H. Y. Zhang, J. Zhang, Q. Ouyang, Y. L. Li, Z. Deng, H. Gong

Abstract: Several new experimental concepts in high-energy particle physics have been proposed in recent years. The physical goals include precisely measuring the properties of particles such as Higgs, Z and W, and even looking for signs of new physics at future colliders. To meet the evolving requirements for particle track detector, Time Projection Chamber(TPC) detector prototype integrated with a UV lase… ▽ More Several new experimental concepts in high-energy particle physics have been proposed in recent years. The physical goals include precisely measuring the properties of particles such as Higgs, Z and W, and even looking for signs of new physics at future colliders. To meet the evolving requirements for particle track detector, Time Projection Chamber(TPC) detector prototype integrated with a UV laser track system was developed for the main track detector at Circular Electron Positron Collider(CEPC). This prototype consists of 6 horizontal laser tracks around TPC detector chamber, a fast electronics readout of 1280 channels, a GEM detector with $200\times 200\,mm^2$ active area, and the DAQ system. The hit resolution, dE/dx resolution and drift velocity were studied by measuring and analyzing using the TPC prototype and UV laser tracks. The dE/dx resolution of the prototype was measured to be $(8.9\pm0.4)\,\%$. Extrapolating this to CEPC TPC with 220 layers and longer track, the resolution was estimated to be $(3.36\pm0.26)\,\%$. All results indicated that the TPC detector prototype integrated with UV laser tracks can work well. △ Less

Submitted 6 June, 2022; originally announced June 2022.

Comments: 17 pages, 11 figures

Search for Neutrinoless Double-Beta Decay of $^{76}$Ge with a Natural Broad Energy Germanium Detector

Authors: CDEX collaboration, W. H. Dai, H. Ma, Q. Yue, Z. She, K. J. Kang, Y. J. Li, M. Agartioglu, H. P. An, J. P. Chang, Y. H. Chen, J. P. Cheng, Z. Deng, C. H. Fang, X. P. Geng, H. Gong, Q. J. Guo, X. Y. Guo, L. He, S. M. He, J. W. Hu, H. X. Huang, T. C. Huang, H. T. Jia, X. Jiang , et al. (61 additional authors not shown)

Abstract: A natural broad energy germanium (BEGe) detector is operated in the China Jinping Underground Laboratory (CJPL) for a feasibility study of building the next generation experiment of the neutrinoless double-beta (0{$νββ$}) decay of $^{76}$Ge. The setup of the prototype facility, characteristics of the BEGe detector, background reduction methods, and data analysis are described in this paper. A back… ▽ More A natural broad energy germanium (BEGe) detector is operated in the China Jinping Underground Laboratory (CJPL) for a feasibility study of building the next generation experiment of the neutrinoless double-beta (0{$νββ$}) decay of $^{76}$Ge. The setup of the prototype facility, characteristics of the BEGe detector, background reduction methods, and data analysis are described in this paper. A background index of 6.4$\times$10$^{-3}$ counts/(keV$\cdot$kg$\cdot$day) is achieved and 1.86 times lower than our previous result of the CDEX-1 detector. No signal is observed with an exposure of 186.4 kg$\cdot$day, thus a limit on the half life of $^{76}$Ge 0$νββ$ decay is set at T$_{1/2}^{0ν}$ $>$ 5.62$\times$10$^{22}$ yr at 90% C.L.. The limit corresponds to an effective Majorana neutrino mass in the range of 4.6 $\sim$ 10.3 eV, dependent on the nuclear matrix elements. △ Less

Submitted 5 August, 2022; v1 submitted 21 May, 2022; originally announced May 2022.

Comments: 10 pages, 15 figures

Journal ref: Physical Review D 106, 032012 (2022)

Prospects for Detecting the Diffuse Supernova Neutrino Background with JUNO

Authors: JUNO Collaboration, Angel Abusleme, Thomas Adam, Shakeel Ahmad, Rizwan Ahmed, Sebastiano Aiello, Muhammad Akram, Fengpeng An, Qi An, Giuseppe Andronico, Nikolay Anfimov, Vito Antonelli, Tatiana Antoshkina, Burin Asavapibhop, João Pedro Athayde Marcondes de André, Didier Auguste, Nikita Balashov, Wander Baldini, Andrea Barresi, Davide Basilico, Eric Baussan, Marco Bellato, Antonio Bergnoli, Thilo Birkenfeld, Sylvie Blin , et al. (577 additional authors not shown)

Abstract: We present the detection potential for the diffuse supernova neutrino background (DSNB) at the Jiangmen Underground Neutrino Observatory (JUNO), using the inverse-beta-decay (IBD) detection channel on free protons. We employ the latest information on the DSNB flux predictions, and investigate in detail the background and its reduction for the DSNB search at JUNO. The atmospheric neutrino induced n… ▽ More We present the detection potential for the diffuse supernova neutrino background (DSNB) at the Jiangmen Underground Neutrino Observatory (JUNO), using the inverse-beta-decay (IBD) detection channel on free protons. We employ the latest information on the DSNB flux predictions, and investigate in detail the background and its reduction for the DSNB search at JUNO. The atmospheric neutrino induced neutral current (NC) background turns out to be the most critical background, whose uncertainty is carefully evaluated from both the spread of model predictions and an envisaged \textit{in situ} measurement. We also make a careful study on the background suppression with the pulse shape discrimination (PSD) and triple coincidence (TC) cuts. With latest DSNB signal predictions, more realistic background evaluation and PSD efficiency optimization, and additional TC cut, JUNO can reach the significance of 3$σ$ for 3 years of data taking, and achieve better than 5$σ$ after 10 years for a reference DSNB model. In the pessimistic scenario of non-observation, JUNO would strongly improve the limits and exclude a significant region of the model parameter space. △ Less

Submitted 13 October, 2022; v1 submitted 18 May, 2022; originally announced May 2022.

Comments: 29 pages, 11 figures, final published version in JCAP

Journal ref: JCAP 10 (2022) 033

Mass Testing and Characterization of 20-inch PMTs for JUNO

Authors: Angel Abusleme, Thomas Adam, Shakeel Ahmad, Rizwan Ahmed, Sebastiano Aiello, Muhammad Akram, Abid Aleem, Tsagkarakis Alexandros, Fengpeng An, Qi An, Giuseppe Andronico, Nikolay Anfimov, Vito Antonelli, Tatiana Antoshkina, Burin Asavapibhop, Joao Pedro Athayde Marcondes de Andre, Didier Auguste, Weidong Bai, Nikita Balashov, Wander Baldini, Andrea Barresi, Davide Basilico, Eric Baussan, Marco Bellato, Antonio Bergnoli , et al. (541 additional authors not shown)

Abstract: Main goal of the JUNO experiment is to determine the neutrino mass ordering using a 20kt liquid-scintillator detector. Its key feature is an excellent energy resolution of at least 3 % at 1 MeV, for which its instruments need to meet a certain quality and thus have to be fully characterized. More than 20,000 20-inch PMTs have been received and assessed by JUNO after a detailed testing program whic… ▽ More Main goal of the JUNO experiment is to determine the neutrino mass ordering using a 20kt liquid-scintillator detector. Its key feature is an excellent energy resolution of at least 3 % at 1 MeV, for which its instruments need to meet a certain quality and thus have to be fully characterized. More than 20,000 20-inch PMTs have been received and assessed by JUNO after a detailed testing program which began in 2017 and elapsed for about four years. Based on this mass characterization and a set of specific requirements, a good quality of all accepted PMTs could be ascertained. This paper presents the performed testing procedure with the designed testing systems as well as the statistical characteristics of all 20-inch PMTs intended to be used in the JUNO experiment, covering more than fifteen performance parameters including the photocathode uniformity. This constitutes the largest sample of 20-inch PMTs ever produced and studied in detail to date, i.e. 15,000 of the newly developed 20-inch MCP-PMTs from Northern Night Vision Technology Co. (NNVT) and 5,000 of dynode PMTs from Hamamatsu Photonics K. K.(HPK). △ Less

Submitted 17 September, 2022; v1 submitted 17 May, 2022; originally announced May 2022.

Constraints on sub-GeV dark matter boosted by cosmic rays from the CDEX-10 experiment at the China Jinping Underground Laboratory

Authors: R. Xu, L. T. Yang, Q. Yue, K. J. Kang, Y. J. Li, M. Agartioglu, H. P. An, J. P. Chang, Y. H. Chen, J. P. Cheng, W. H. Dai, Z. Deng, C. H. Fang, X. P. Geng, H. Gong, X. Y. Guo, Q. J. Guo, L. He, S. M. He, J. W. Hu, H. X. Huang, T. C. Huang, H. T. Jia, X. Jiang, H. B. Li , et al. (60 additional authors not shown)

Abstract: We present new constraints on light dark matter boosted by cosmic rays (CRDM) using the 205.4 kg day data of the CDEX-10 experiment conducted at the China Jinping Underground Laboratory. The Monte Carlo simulation package CJPL\_ESS was employed to evaluate the Earth shielding effect. Several key factors have been introduced and discussed in our CRDM analysis, including the contributions from heavi… ▽ More We present new constraints on light dark matter boosted by cosmic rays (CRDM) using the 205.4 kg day data of the CDEX-10 experiment conducted at the China Jinping Underground Laboratory. The Monte Carlo simulation package CJPL\_ESS was employed to evaluate the Earth shielding effect. Several key factors have been introduced and discussed in our CRDM analysis, including the contributions from heavier CR nuclei than proton and helium, the inhomogeneity of CR distribution, and the impact of the form factor in the Earth attenuation calculation. Our result excludes the dark matter--nucleon elastic scattering cross-section region from $1.7\times 10^{-30}$ to $10^{-26}~\rm cm^2$ for dark matter of 10 keV$/c^2$ to 1 GeV$/c^2$. △ Less

Submitted 16 September, 2022; v1 submitted 5 January, 2022; originally announced January 2022.

Comments: 9 pages, 7 figures. Version updated to match PRD version

Journal ref: Phys. Rev. D 106, 052008 (2022)

Studies of the Earth shielding effect to direct dark matter searches at the China Jinping Underground Laboratory

Authors: Z. Z. Liu, L. T. Yang, Q. Yue, C. H. Yeh, K. J. Kang, Y. J. Li, M. Agartioglu, H. P. An, J. P. Chang, J. H. Chen, Y. H. Chen, J. P. Cheng, W. H. Dai, Z. Deng, C. H. Fang, X. P. Geng, H. Gong, X. Y. Guo, Q. J. Guo, L. He, S. M. He, J. W. Hu, H. X. Huang, T. C. Huang, H. T. Jia , et al. (58 additional authors not shown)

Abstract: Dark matter direct detection experiments mostly operate at deep underground laboratories. It is necessary to consider shielding effect of the Earth, especially for dark matter particles interacting with a large cross section. We analyzed and simulated the Earth shielding effect for dark matter at the China Jinping Underground Laboratory (CJPL) with a simulation package, CJPL Earth Shielding Simula… ▽ More Dark matter direct detection experiments mostly operate at deep underground laboratories. It is necessary to consider shielding effect of the Earth, especially for dark matter particles interacting with a large cross section. We analyzed and simulated the Earth shielding effect for dark matter at the China Jinping Underground Laboratory (CJPL) with a simulation package, CJPL Earth Shielding Simulation code (CJPL\_ESS), which is applicable to other underground locations. The further constraints on the $χ$-N cross section exclusion regions are derived based on the studies with CDEX experiment data. △ Less

Submitted 9 March, 2022; v1 submitted 22 November, 2021; originally announced November 2021.

Comments: 8 pages, 8 figures, 2 tables. Version updated to match PRD version

Journal ref: Phys. Rev. D 105, 052005 (2022)

Radioactivity control strategy for the JUNO detector

Authors: JUNO collaboration, Angel Abusleme, Thomas Adam, Shakeel Ahmad, Rizwan Ahmed, Sebastiano Aiello, Muhammad Akram, Fengpeng An, Qi An, Giuseppe Andronico, Nikolay Anfimov, Vito Antonelli, Tatiana Antoshkina, Burin Asavapibhop, João Pedro Athayde Marcondes de André, Didier Auguste, Andrej Babic, Wander Baldini, Andrea Barresi, Davide Basilico, Eric Baussan, Marco Bellato, Antonio Bergnoli, Thilo Birkenfeld, Sylvie Blin , et al. (578 additional authors not shown)

Abstract: JUNO is a massive liquid scintillator detector with a primary scientific goal of determining the neutrino mass ordering by studying the oscillated anti-neutrino flux coming from two nuclear power plants at 53 km distance. The expected signal anti-neutrino interaction rate is only 60 counts per day, therefore a careful control of the background sources due to radioactivity is critical. In particula… ▽ More JUNO is a massive liquid scintillator detector with a primary scientific goal of determining the neutrino mass ordering by studying the oscillated anti-neutrino flux coming from two nuclear power plants at 53 km distance. The expected signal anti-neutrino interaction rate is only 60 counts per day, therefore a careful control of the background sources due to radioactivity is critical. In particular, natural radioactivity present in all materials and in the environment represents a serious issue that could impair the sensitivity of the experiment if appropriate countermeasures were not foreseen. In this paper we discuss the background reduction strategies undertaken by the JUNO collaboration to reduce at minimum the impact of natural radioactivity. We describe our efforts for an optimized experimental design, a careful material screening and accurate detector production handling, and a constant control of the expected results through a meticulous Monte Carlo simulation program. We show that all these actions should allow us to keep the background count rate safely below the target value of 10 Hz in the default fiducial volume, above an energy threshold of 0.7 MeV. △ Less

Submitted 13 October, 2021; v1 submitted 8 July, 2021; originally announced July 2021.

Comments: 35 pages, 12 figures

The Design and Sensitivity of JUNO's scintillator radiopurity pre-detector OSIRIS

Authors: JUNO Collaboration, Angel Abusleme, Thomas Adam, Shakeel Ahmad, Rizwan Ahmed, Sebastiano Aiello, Muhammad Akram, Fengpeng An, Guangpeng An, Qi An, Giuseppe Andronico, Nikolay Anfimov, Vito Antonelli, Tatiana Antoshkina, Burin Asavapibhop, João Pedro Athayde Marcondes de André, Didier Auguste, Andrej Babic, Wander Baldini, Andrea Barresi, Davide Basilico, Eric Baussan, Marco Bellato, Antonio Bergnoli, Thilo Birkenfeld , et al. (582 additional authors not shown)

Abstract: The OSIRIS detector is a subsystem of the liquid scintillator fillling chain of the JUNO reactor neutrino experiment. Its purpose is to validate the radiopurity of the scintillator to assure that all components of the JUNO scintillator system work to specifications and only neutrino-grade scintillator is filled into the JUNO Central Detector. The aspired sensitivity level of $10^{-16}$ g/g of… ▽ More The OSIRIS detector is a subsystem of the liquid scintillator fillling chain of the JUNO reactor neutrino experiment. Its purpose is to validate the radiopurity of the scintillator to assure that all components of the JUNO scintillator system work to specifications and only neutrino-grade scintillator is filled into the JUNO Central Detector. The aspired sensitivity level of $10^{-16}$ g/g of $^{238}$U and $^{232}$Th requires a large ($\sim$20 m$^3$) detection volume and ultralow background levels. The present paper reports on the design and major components of the OSIRIS detector, the detector simulation as well as the measuring strategies foreseen and the sensitivity levels to U/Th that can be reached in this setup. △ Less

Submitted 31 March, 2021; originally announced March 2021.

Comments: 32 pages, 22 figures

Feasibility study of TPC detector at high luminosity $Z$ pole on the circular collider

Authors: Zhiyang Yuan, Huirong Qi, Yue Chang, Ye Wu, Hongyu Zhang, Jian Zhang, Yuanbo Chen, Yiming Cai, Yulan Li, Zhi Deng, Hui Gong

Abstract: With the development of the circular collider, it is necessary to make accurate physics experimental measurements of particle properties at higher luminosity $Z$ pole. Micro-pattern gaseous detectors (MPGDs), which contain Gaseous Electron Multiplier (GEM) and Micro-mesh gaseous structures (Micromegas), have excellent potential for development as the readout devices of the time projection chamber… ▽ More With the development of the circular collider, it is necessary to make accurate physics experimental measurements of particle properties at higher luminosity $Z$ pole. Micro-pattern gaseous detectors (MPGDs), which contain Gaseous Electron Multiplier (GEM) and Micro-mesh gaseous structures (Micromegas), have excellent potential for development as the readout devices of the time projection chamber (TPC) tracker detector. To meet the updated physics requirements of the high luminosity $Z$ from the preliminary concept design report (preCDR) to concept design report (CDR) at the circular electron positron collider (CEPC), In this paper, the space charge distortion of the TPC detector is simulated with the CEPC beam structure. Using the multi-physics simulation software package, the distribution of ion estimated by Geant4 is used as the input for the differential equation, and the relationship between the ion density distribution and electric field in the detector chamber is simulated. These simulation results show that the maximum deviation for Higgs $\mathcal{O}$(25 $μ$m) meets the performance requirements in CEPC TPC detector at the high luminosity $Z$ pole, while it is still a considerable challenge for $Z$ pole, with the maximum deviation $\mathcal{O}$($>100~μ$m). According to the previous developments, the cascaded structure of GEM and Micromegas detector has been measured. The new considerations of the detector's requirements were given, the gain needs to be reached to about 2000 with IBF$\times$Gain under 0.1, and IBF means the ions back flow ratio of the detector. The pixel TPC is a potential option to replace the traditional MPGDs with the low gain, low occupancy, and outstanding pattern recognition. Finally, some update parameters and experiments results were compared. △ Less

Submitted 18 February, 2021; originally announced February 2021.

Comments: 7 pages, 8 png figures

Construction and On-site Performance of the LHAASO WFCTA Camera

Authors: F. Aharonian, Q. An, Axikegu, L. X. Bai, Y. X. Bai, Y. W. Bao, D. Bastieri, X. J. Bi, Y. J. Bi, H. Cai, J. T. Cai, Z. Cao, Z. Cao, J. Chang, J. F. Chang, X. C. Chang, B. M. Chen, J. Chen, L. Chen, L. Chen, L. Chen, M. J. Chen, M. L. Chen, Q. H. Chen, S. H. Chen , et al. (234 additional authors not shown)

Abstract: The focal plane camera is the core component of the Wide Field-of-view Cherenkov/fluorescence Telescope Array (WFCTA) of the Large High-Altitude Air Shower Observatory (LHAASO). Because of the capability of working under moonlight without aging, silicon photomultipliers (SiPM) have been proven to be not only an alternative but also an improvement to conventional photomultiplier tubes (PMT) in this… ▽ More The focal plane camera is the core component of the Wide Field-of-view Cherenkov/fluorescence Telescope Array (WFCTA) of the Large High-Altitude Air Shower Observatory (LHAASO). Because of the capability of working under moonlight without aging, silicon photomultipliers (SiPM) have been proven to be not only an alternative but also an improvement to conventional photomultiplier tubes (PMT) in this application. Eighteen SiPM-based cameras with square light funnels have been built for WFCTA. The telescopes have collected more than 100 million cosmic ray events and preliminary results indicate that these cameras are capable of working under moonlight. The characteristics of the light funnels and SiPMs pose challenges (e.g. dynamic range, dark count rate, assembly techniques). In this paper, we present the design features, manufacturing techniques and performances of these cameras. Finally, the test facilities, the test methods and results of SiPMs in the cameras are reported here. △ Less

Submitted 4 July, 2021; v1 submitted 29 December, 2020; originally announced December 2020.

Comments: 45 pages, 21 figures, article

Journal ref: Eur. Phys. J. C 81, 657 (2021)

Calibration Strategy of the JUNO Experiment

Authors: JUNO collaboration, Angel Abusleme, Thomas Adam, Shakeel Ahmad, Rizwan Ahmed, Sebastiano Aiello, Muhammad Akram, Fengpeng An, Guangpeng An, Qi An, Giuseppe Andronico, Nikolay Anfimov, Vito Antonelli, Tatiana Antoshkina, Burin Asavapibhop, João Pedro Athayde Marcondes de André, Didier Auguste, Andrej Babic, Wander Baldini, Andrea Barresi, Eric Baussan, Marco Bellato, Antonio Bergnoli, Enrico Bernieri, Thilo Birkenfeld , et al. (571 additional authors not shown)

Abstract: We present the calibration strategy for the 20 kton liquid scintillator central detector of the Jiangmen Underground Neutrino Observatory (JUNO). By utilizing a comprehensive multiple-source and multiple-positional calibration program, in combination with a novel dual calorimetry technique exploiting two independent photosensors and readout systems, we demonstrate that the JUNO central detector ca… ▽ More We present the calibration strategy for the 20 kton liquid scintillator central detector of the Jiangmen Underground Neutrino Observatory (JUNO). By utilizing a comprehensive multiple-source and multiple-positional calibration program, in combination with a novel dual calorimetry technique exploiting two independent photosensors and readout systems, we demonstrate that the JUNO central detector can achieve a better than 1% energy linearity and a 3% effective energy resolution, required by the neutrino mass ordering determination. △ Less

Submitted 20 January, 2021; v1 submitted 12 November, 2020; originally announced November 2020.

First experimental constraints on WIMP couplings in the effective field theory framework from CDEX

Authors: Y. Wang, Z. Zeng, Q. Yue, L. T. Yang, K. J. Kang, Y. J. Li, M. Agartioglu, H. P. An, J. P. Chang, J. H. Chen, Y. H. Chen, J. P. Cheng, C. Y. Chiang, W. H. Dai, Z. Deng, C. H. Fang, X. P. Geng, H. Gong, Q. J. Guo, X. Y. Guo, H. J. He, L. He, S. M. He, J. W. Hu, T. C. Huang , et al. (63 additional authors not shown)

Abstract: We present weakly interacting massive particles (WIMPs) search results performed using two approaches of effective field theory from the China Dark Matter Experiment (CDEX), based on the data from both CDEX-1B and CDEX-10 stages. In the nonrelativistic effective field theory approach, both time-integrated and annual modulation analyses were used to set new limits for the coupling of WIMP-nucleon e… ▽ More We present weakly interacting massive particles (WIMPs) search results performed using two approaches of effective field theory from the China Dark Matter Experiment (CDEX), based on the data from both CDEX-1B and CDEX-10 stages. In the nonrelativistic effective field theory approach, both time-integrated and annual modulation analyses were used to set new limits for the coupling of WIMP-nucleon effective operators at 90% confidence level (C.L.) and improve over the current bounds in the low $m_χ$ region. In the chiral effective field theory approach, data from CDEX-10 were used to set an upper limit on WIMP-pion coupling at 90% C.L. We for the first time extended the limit to the $m_χ<$ 6 GeV/$c^2$ region. △ Less

Submitted 26 April, 2021; v1 submitted 30 July, 2020; originally announced July 2020.

Comments: version accepted by Science China-PMA, 8 pages, 8 figures

Journal ref: Sci. China-Phys. Mech. Astron. 64, 281011 (2021)

Optimization of the JUNO liquid scintillator composition using a Daya Bay antineutrino detector

Authors: Daya Bay, JUNO collaborations, :, A. Abusleme, T. Adam, S. Ahmad, S. Aiello, M. Akram, N. Ali, F. P. An, G. P. An, Q. An, G. Andronico, N. Anfimov, V. Antonelli, T. Antoshkina, B. Asavapibhop, J. P. A. M. de André, A. Babic, A. B. Balantekin, W. Baldini, M. Baldoncini, H. R. Band, A. Barresi, E. Baussan , et al. (642 additional authors not shown)

Abstract: To maximize the light yield of the liquid scintillator (LS) for the Jiangmen Underground Neutrino Observatory (JUNO), a 20 t LS sample was produced in a pilot plant at Daya Bay. The optical properties of the new LS in various compositions were studied by replacing the gadolinium-loaded LS in one antineutrino detector. The concentrations of the fluor, PPO, and the wavelength shifter, bis-MSB, were… ▽ More To maximize the light yield of the liquid scintillator (LS) for the Jiangmen Underground Neutrino Observatory (JUNO), a 20 t LS sample was produced in a pilot plant at Daya Bay. The optical properties of the new LS in various compositions were studied by replacing the gadolinium-loaded LS in one antineutrino detector. The concentrations of the fluor, PPO, and the wavelength shifter, bis-MSB, were increased in 12 steps from 0.5 g/L and <0.01 mg/L to 4 g/L and 13 mg/L, respectively. The numbers of total detected photoelectrons suggest that, with the optically purified solvent, the bis-MSB concentration does not need to be more than 4 mg/L. To bridge the one order of magnitude in the detector size difference between Daya Bay and JUNO, the Daya Bay data were used to tune the parameters of a newly developed optical model. Then, the model and tuned parameters were used in the JUNO simulation. This enabled to determine the optimal composition for the JUNO LS: purified solvent LAB with 2.5 g/L PPO, and 1 to 4 mg/L bis-MSB. △ Less

Submitted 1 July, 2020; originally announced July 2020.

Comments: 13 pages, 8 figures

Search For Electron-Antineutrinos Associated With Gravitational-Wave Events GW150914, GW151012, GW151226, GW170104, GW170608, GW170814, and GW170817 at Daya Bay

Authors: F. P. An, A. B. Balantekin, H. R. Band, M. Bishai, S. Blyth, G. F. Cao, J. Cao, J. F. Chang, Y. Chang, H. S. Chen, S. M. Chen, Y. Chen, Y. X. Chen, J. Cheng, Z. K. Cheng, J. J. Cherwinka, M. C. Chu, J. P. Cummings, O. Dalager, F. S. Deng, Y. Y. Ding, M. V. Diwan, T. Dohnal, J. Dove, M. Dvorak , et al. (161 additional authors not shown)

Abstract: Providing a possible connection between neutrino emission and gravitational-wave (GW) bursts is important to our understanding of the physical processes that occur when black holes or neutron stars merge. In the Daya Bay experiment, using data collected from December 2011 to August 2017, a search has been performed for electron-antineutrino signals coinciding with detected GW events, including GW1… ▽ More Providing a possible connection between neutrino emission and gravitational-wave (GW) bursts is important to our understanding of the physical processes that occur when black holes or neutron stars merge. In the Daya Bay experiment, using data collected from December 2011 to August 2017, a search has been performed for electron-antineutrino signals coinciding with detected GW events, including GW150914, GW151012, GW151226, GW170104, GW170608, GW170814, and GW170817. We used three time windows of $\mathrm{\pm 10~s}$, $\mathrm{\pm 500~s}$, and $\mathrm{\pm 1000~s}$ relative to the occurrence of the GW events, and a neutrino energy range of 1.8 to 100 MeV to search for correlated neutrino candidates. The detected electron-antineutrino candidates are consistent with the expected background rates for all the three time windows. Assuming monochromatic spectra, we found upper limits (90% confidence level) on electron-antineutrino fluence of $(1.13~-~2.44) \times 10^{11}~\rm{cm^{-2}}$ at 5 MeV to $8.0 \times 10^{7}~\rm{cm^{-2}}$ at 100 MeV for the three time windows. Under the assumption of a Fermi-Dirac spectrum, the upper limits were found to be $(5.4~-~7.0)\times 10^{9}~\rm{cm^{-2}}$ for the three time windows. △ Less

Submitted 14 September, 2020; v1 submitted 27 June, 2020; originally announced June 2020.

Comments: 16 pages, 12 figures, 9 tables

Feasibility and physics potential of detecting $^8$B solar neutrinos at JUNO

Authors: JUNO collaboration, Angel Abusleme, Thomas Adam, Shakeel Ahmad, Sebastiano Aiello, Muhammad Akram, Nawab Ali, Fengpeng An, Guangpeng An, Qi An, Giuseppe Andronico, Nikolay Anfimov, Vito Antonelli, Tatiana Antoshkina, Burin Asavapibhop, João Pedro Athayde Marcondes de André, Didier Auguste, Andrej Babic, Wander Baldini, Andrea Barresi, Eric Baussan, Marco Bellato, Antonio Bergnoli, Enrico Bernieri, David Biare , et al. (572 additional authors not shown)

Abstract: The Jiangmen Underground Neutrino Observatory~(JUNO) features a 20~kt multi-purpose underground liquid scintillator sphere as its main detector. Some of JUNO's features make it an excellent experiment for $^8$B solar neutrino measurements, such as its low-energy threshold, its high energy resolution compared to water Cherenkov detectors, and its much large target mass compared to previous liquid s… ▽ More The Jiangmen Underground Neutrino Observatory~(JUNO) features a 20~kt multi-purpose underground liquid scintillator sphere as its main detector. Some of JUNO's features make it an excellent experiment for $^8$B solar neutrino measurements, such as its low-energy threshold, its high energy resolution compared to water Cherenkov detectors, and its much large target mass compared to previous liquid scintillator detectors. In this paper we present a comprehensive assessment of JUNO's potential for detecting $^8$B solar neutrinos via the neutrino-electron elastic scattering process. A reduced 2~MeV threshold on the recoil electron energy is found to be achievable assuming the intrinsic radioactive background $^{238}$U and $^{232}$Th in the liquid scintillator can be controlled to 10$^{-17}$~g/g. With ten years of data taking, about 60,000 signal and 30,000 background events are expected. This large sample will enable an examination of the distortion of the recoil electron spectrum that is dominated by the neutrino flavor transformation in the dense solar matter, which will shed new light on the tension between the measured electron spectra and the predictions of the standard three-flavor neutrino oscillation framework. If $Δm^{2}_{21}=4.8\times10^{-5}~(7.5\times10^{-5})$~eV$^{2}$, JUNO can provide evidence of neutrino oscillation in the Earth at the about 3$σ$~(2$σ$) level by measuring the non-zero signal rate variation with respect to the solar zenith angle. Moveover, JUNO can simultaneously measure $Δm^2_{21}$ using $^8$B solar neutrinos to a precision of 20\% or better depending on the central value and to sub-percent precision using reactor antineutrinos. A comparison of these two measurements from the same detector will help elucidate the current tension between the value of $Δm^2_{21}$ reported by solar neutrino experiments and the KamLAND experiment. △ Less

Submitted 21 June, 2020; originally announced June 2020.

Comments: 29 pages, 14 plots, 7 tables

UO2/BeO interfacial thermal resistance and its effect on fuel thermal conductivity

Authors: Xueyan Zhu, Rui Gao, Hengfeng Gong, Tong Liu, De-Ye Lin, Haifeng Song

Abstract: UO2/BeO interfacial thermal resistance (ITR) is calculated by diffuse mismatch model (DMM) and the effects of ITR on UO2-BeO thermal conductivity are investigated. ITR predicted by DMM is on the order of 10-9 m2K/W. Using this ITR, UO2-BeO thermal conductivities are calculated by theoretical models and compared with experimental data. The results indicate that DMM prediction is applicable to the i… ▽ More UO2/BeO interfacial thermal resistance (ITR) is calculated by diffuse mismatch model (DMM) and the effects of ITR on UO2-BeO thermal conductivity are investigated. ITR predicted by DMM is on the order of 10-9 m2K/W. Using this ITR, UO2-BeO thermal conductivities are calculated by theoretical models and compared with experimental data. The results indicate that DMM prediction is applicable to the interface between UO2 and dispersed BeO, while not applicable to the interface between UO2 and continuous BeO. If the thermal conductivity of UO2 containing continuous BeO was to be in agreement with experimental data, its ITR should be on the order of 10-6 - 10-5 m2K/W. Therefore, the vibrational mismatch between UO2 and BeO considered by DMM is the major mechanism for attenuating the heat flux through UO2/dispersed-BeO interface, but not for UO2/continuous-BeO interface. Furthermore, it is found that the presence of ITR leads to the dependence of the thermal conductivity of UO2 containing dispersed BeO on BeO size. With the decrease in BeO size, UO2-BeO thermal conductivity decreases. When BeO size is smaller than a critical value, UO2-BeO thermal conductivity becomes even smaller than UO2 thermal conductivity. For UO2 containing continuous BeO, the thermal conductivity decreases with the decrease in the size of UO2 granule surrounded by BeO, but not necessarily smaller than UO2 thermal conductivity. Under a critical temperature, UO2-BeO thermal conductivity is always larger than UO2 thermal conductivity. Above the critical temperature, UO2-BeO thermal conductivity is larger than UO2 thermal conductivity only when UO2 granule size is large enough. The conditions for achieving the targeted enhancement of UO2 thermal conductivity by doping with BeO are derived. These conditions can be used to design and optimize the distribution, content, size of BeO, and the size of UO2 granule. △ Less

Submitted 20 June, 2020; originally announced June 2020.

Journal ref: Annals of Nuclear Energy, Volume 154, May 2021, 108102

TAO Conceptual Design Report: A Precision Measurement of the Reactor Antineutrino Spectrum with Sub-percent Energy Resolution

Authors: JUNO Collaboration, Angel Abusleme, Thomas Adam, Shakeel Ahmad, Sebastiano Aiello, Muhammad Akram, Nawab Ali, Fengpeng An, Guangpeng An, Qi An, Giuseppe Andronico, Nikolay Anfimov, Vito Antonelli, Tatiana Antoshkina, Burin Asavapibhop, João Pedro Athayde Marcondes de André, Didier Auguste, Andrej Babic, Wander Baldini, Andrea Barresi, Eric Baussan, Marco Bellato, Antonio Bergnoli, Enrico Bernieri, David Biare , et al. (568 additional authors not shown)

Abstract: The Taishan Antineutrino Observatory (TAO, also known as JUNO-TAO) is a satellite experiment of the Jiangmen Underground Neutrino Observatory (JUNO). A ton-level liquid scintillator detector will be placed at about 30 m from a core of the Taishan Nuclear Power Plant. The reactor antineutrino spectrum will be measured with sub-percent energy resolution, to provide a reference spectrum for future re… ▽ More The Taishan Antineutrino Observatory (TAO, also known as JUNO-TAO) is a satellite experiment of the Jiangmen Underground Neutrino Observatory (JUNO). A ton-level liquid scintillator detector will be placed at about 30 m from a core of the Taishan Nuclear Power Plant. The reactor antineutrino spectrum will be measured with sub-percent energy resolution, to provide a reference spectrum for future reactor neutrino experiments, and to provide a benchmark measurement to test nuclear databases. A spherical acrylic vessel containing 2.8 ton gadolinium-doped liquid scintillator will be viewed by 10 m^2 Silicon Photomultipliers (SiPMs) of >50% photon detection efficiency with almost full coverage. The photoelectron yield is about 4500 per MeV, an order higher than any existing large-scale liquid scintillator detectors. The detector operates at -50 degree C to lower the dark noise of SiPMs to an acceptable level. The detector will measure about 2000 reactor antineutrinos per day, and is designed to be well shielded from cosmogenic backgrounds and ambient radioactivities to have about 10% background-to-signal ratio. The experiment is expected to start operation in 2022. △ Less

Submitted 18 May, 2020; originally announced May 2020.

Comments: 134 pages, 114 figures

Capability of detecting low energy events in JUNO Central Detector

Authors: X. Fang, Y. Zhang, G. H. Gong, G. F. Cao, T. Lin, C. W. Yang, W. D. Li

Abstract: The Jiangmen Underground Neutrino Observatory (JUNO) is an experimental project designed to determine the neutrino mass ordering and probe the fundamental properties of the neutrino oscillations. The JUNO central detector is a spherical liquid scintillator detector with a diameter of 35.4 m and equipped with approximately 18,000 20-inch PMTs. A trigger threshold of 0.5 MeV can be easily achieved b… ▽ More The Jiangmen Underground Neutrino Observatory (JUNO) is an experimental project designed to determine the neutrino mass ordering and probe the fundamental properties of the neutrino oscillations. The JUNO central detector is a spherical liquid scintillator detector with a diameter of 35.4 m and equipped with approximately 18,000 20-inch PMTs. A trigger threshold of 0.5 MeV can be easily achieved by using a common multiplicity trigger and can meet the requirements for measuring neutrino mass ordering. However, it is essential to further reduce the trigger threshold for detecting solar neutrinos and supernova neutrinos. A sophisticated trigger scheme is proposed to achieve a low energy threshold by reducing the level of low energy radioactivity and dark noise coincidence. With the new trigger scheme, the events rate of the central detector from different types of sources have been carefully studied by using a detailed detector simulation. It shows that the trigger threshold can be reduced to 0.2 MeV, or even 0.1 MeV, if the concentration of $^{14}$C in liquid scintillator can be well controlled. △ Less

Submitted 4 December, 2019; originally announced December 2019.

Improved limits on solar axions and bosonic dark matter from the CDEX-1B experiment using the profile likelihood ratio method

Authors: Y. Wang, Q. Yue, S. K. Liu, K. J. Kang, Y. J. Li, H. P. An, J. P. Chang, J. H. Chen, Y. H. Chen, J. P. Cheng, W. H. Dai, Z. Deng, X. P. Geng, H. Gong, P. Gu, X. Y. Guo, H. T. He, L. He, S. M. He, J. W. Hu, H. X. Huang, T. C. Huang, L. P. Jia, H. B. Li, H. Li , et al. (55 additional authors not shown)

Abstract: We present the improved constraints on couplings of solar axions and more generic bosonic dark matter particles using 737.1 kg-days of data from the CDEX-1B experiment. The CDEX-1B experiment, located at the China Jinping Underground Laboratory, primarily aims at the direct detection of weakly interacting massive particles using a p-type point-contact germanium detector. We adopt the profile likel… ▽ More We present the improved constraints on couplings of solar axions and more generic bosonic dark matter particles using 737.1 kg-days of data from the CDEX-1B experiment. The CDEX-1B experiment, located at the China Jinping Underground Laboratory, primarily aims at the direct detection of weakly interacting massive particles using a p-type point-contact germanium detector. We adopt the profile likelihood ratio method for analysis of data in the presence of backgrounds. An energy threshold of 160 eV was achieved, much better than the 475 eV of CDEX-1A with an exposure of 335.6 kg-days. This significantly improves the sensitivity for the bosonic dark matter below 0.8 keV among germanium detectors. Limits are also placed on the coupling $g_{Ae} < 2.48 \times 10^{-11}$ from Compton, bremsstrahlung, atomic-recombination and de-excitation channels and $g^{eff}_{AN} \times g_{Ae} < 4.14 \times 10^{-17}$ from a $^{57}$Fe M1 transition at 90\% confidence level. △ Less

Submitted 26 April, 2021; v1 submitted 8 November, 2019; originally announced November 2019.

Comments: version accepted by PRD, 9 pages, 11 figures

Journal ref: Phys. Rev. D 101, 052003 (2020)

Direct Detection Constraints on Dark Photons with CDEX-10 Experiment at the China Jinping Underground Laboratory

Authors: Z. She, L. P. Jia, Q. Yue, H. Ma, K. J. Kang, Y. J. Li, M. Agartioglu, H. P. An, J. P. Chang, J. H. Chen, Y. H. Chen, J. P. Cheng, W. H. Dai, Z. Deng, X. P. Geng, H. Gong, P. Gu, Q. J. Guo, X. Y. Guo, L. He, S. M. He, H. T. He, J. W. Hu, T. C. Huang, H. X. Huang , et al. (59 additional authors not shown)

Abstract: We report constraints on the dark photon effective kinetic mixing parameter ($κ$) with data taken from two ${p}$-type point-contact germanium detectors of the CDEX-10 experiment at the China Jinping Underground Laboratory. The 90\% confidence level upper limits on $κ$ of solar dark photon from 205.4 kg-day exposure are derived, probing new parameter space with masses (${m_V}$) from 10 to 300 eV/… ▽ More We report constraints on the dark photon effective kinetic mixing parameter ($κ$) with data taken from two ${p}$-type point-contact germanium detectors of the CDEX-10 experiment at the China Jinping Underground Laboratory. The 90\% confidence level upper limits on $κ$ of solar dark photon from 205.4 kg-day exposure are derived, probing new parameter space with masses (${m_V}$) from 10 to 300 eV/${c^2}$ in direct detection experiments. Considering dark photon as the cosmological dark matter, limits at 90\% confidence level with ${m_V}$ from 0.1 to 4.0 keV/${c^2}$ are set from 449.6 kg-day data, with a minimum of ${\rm{κ=1.3 \times 10^{-15}}}$ at ${\rm{m_V=200\ eV/c^2}}$. △ Less

Submitted 18 March, 2020; v1 submitted 29 October, 2019; originally announced October 2019.

Comments: 5 pages, 6 figures

Journal ref: Phys. Rev. Lett. 124, 111301 (2020)