Showing 1–15 of 15 results for author: Lanza, C

Symmetry extension by condensation defects II: general dimensions and higher-groups

Authors: Matteo Bertolini, Lorenzo Di Pietro, Stefano C. Lanza, Antonio Santaniello

Abstract: We discuss a class of symmetry structures in general spacetime dimension that arise when gauging symmetries in theories with a cubic 't Hooft anomaly. The anomaly mixes two Abelian discrete symmetries $A$ and $B$ with a characteristic class for an additional symmetry $C$, and we gauge $A\times B$. The novelty of this construction is that the resulting symmetry structure involves certain condensati… ▽ More We discuss a class of symmetry structures in general spacetime dimension that arise when gauging symmetries in theories with a cubic 't Hooft anomaly. The anomaly mixes two Abelian discrete symmetries $A$ and $B$ with a characteristic class for an additional symmetry $C$, and we gauge $A\times B$. The novelty of this construction is that the resulting symmetry structure involves certain condensation defects of the dual symmetry $\widehat{A}\times\widehat{B}$. Specifically, these defects generate an invertible symmetry that extends $C$, either as an ordinary group extension or as a higher-group, depending on the characteristic class. We describe the corresponding charged operators and states, and illustrate the mechanism in several examples. △ Less

Submitted 6 August, 2026; v1 submitted 17 July, 2026; originally announced July 2026.

Comments: 37 pages + appendices, 22 figures, 1 table. v2: typos corrected, references and acknowledgments added

Twistoptics in Planar Heterostructures with an Arbitrary Number of Rotated 3D Thin Layers and 2D Conductive Sheets

Authors: Christian Lanza, José Álvarez-Cuervo, Kirill V. Voronin, Gonzalo Álvarez-Pérez, Aitana Tarazaga Martín-Luengo, Javier Martín-Sánchez, Alexey Y. Nikitin, Pablo Alonso-González

Abstract: Twistoptics has recently emerged as a branch of nano-optics that explores light propagation in stacks of thin anisotropic layers rotated relative to one another. The concept is particularly relevant for polaritons -- hybrid light-matter quasiparticles -- in van der Waals (vdW) materials, where strong in-plane anisotropy and deep subwavelength confinement make the polaritonic dispersion highly sens… ▽ More Twistoptics has recently emerged as a branch of nano-optics that explores light propagation in stacks of thin anisotropic layers rotated relative to one another. The concept is particularly relevant for polaritons -- hybrid light-matter quasiparticles -- in van der Waals (vdW) materials, where strong in-plane anisotropy and deep subwavelength confinement make the polaritonic dispersion highly sensitive to interlayer twist angles. This sensitivity enables exotic phenomena such as canalization, i.e., diffraction-free propagation, with potential applications ranging from thermal management to super-resolution imaging. Despite rapid progress, a general analytical framework to describe polariton propagation in twisted planar heterostructures has been missing. Here we present an analytical model for planar stacks comprising an arbitrary number of finite-thickness anisotropic (biaxial) layers and infinitesimally thin anisotropic conductive sheets. The formalism and its high-momentum and thin-film approximations predict key polaritonic observables, such as wavelength, propagation length, and electromagnetic field distributions. We also provide open-access numerical scripts implementing the model to support their practical use. Together, these results provide a general theoretical foundation for twistoptics and should facilitate the discovery and accelerate the implementation of twist-engineered polaritonic phenomena across the electromagnetic spectrum. △ Less

Submitted 15 April, 2026; originally announced April 2026.

Fast Programming of In-Plane Hyperbolic Phonon Polariton Optics Through van der Waals Crystals using the Phase-Change Material In3SbTe2

Authors: Lina Jäckering, Umberto Saldarelli, Aaron Moos, Lukas Conrads, Enrique Terán-García, Christian Lanza, Aitana Tarazaga Martín-Luengo, Gonzalo Álvarez-Pérez, Pablo Alonso-González, Matthias Wuttig, Thomas Taubner

Abstract: The high directionality of hyperbolic phonon polaritons (HPhPs) has opened radically new ways to route and steer the flow of energy at the nanoscale. However, launching HPhPs requires fabricating efficient and precisely aligned polariton launching structures, which remains time-consuming and expensive with conventional nanofabrication approaches. Recently, using optical laser pulses, polariton lau… ▽ More The high directionality of hyperbolic phonon polaritons (HPhPs) has opened radically new ways to route and steer the flow of energy at the nanoscale. However, launching HPhPs requires fabricating efficient and precisely aligned polariton launching structures, which remains time-consuming and expensive with conventional nanofabrication approaches. Recently, using optical laser pulses, polariton launching structures have been programmed into the plasmonic phase-change material In3SbTe2. Here, we leverage this approach to reconfigure HPhPs by programming a variety of launching and confining nanostructures through α-MoO3 flakes deposited onto In3SbTe2. Importantly, optical programming after flake deposition enables alignment of launching stripes to the [001]-axis of the flake, essential to control the directional polariton propagation. We showcase these capabilities in a variety of structures: i) an optically programmed disk, showing similar tuning ranges and confinement as focusing by gold disks; and ii) a cavity for in-plane HPhPs created by reconfiguring the single disk to a double disk structure, tailoring the confinement by simply reprogramming the disk distance. Our fabrication scheme offers fast turn-around times, flexible alignment and the opportunity to reconfigure the structures. Thus, it is a fast, efficient and versatile way to tailor propagation and confinement of highly directional polaritons on demand. △ Less

Submitted 11 March, 2026; originally announced March 2026.

Degradation of Feature Space in Continual Learning

Authors: Chiara Lanza, Roberto Pereira, Marco Miozzo, Eduard Angelats, Paolo Dini

Abstract: Centralized training is the standard paradigm in deep learning, enabling models to learn from a unified dataset in a single location. In such setup, isotropic feature distributions naturally arise as a mean to support well-structured and generalizable representations. In contrast, continual learning operates on streaming and non-stationary data, and trains models incrementally, inherently facing t… ▽ More Centralized training is the standard paradigm in deep learning, enabling models to learn from a unified dataset in a single location. In such setup, isotropic feature distributions naturally arise as a mean to support well-structured and generalizable representations. In contrast, continual learning operates on streaming and non-stationary data, and trains models incrementally, inherently facing the well-known plasticity-stability dilemma. In such settings, learning dynamics tends to yield increasingly anisotropic feature space. This arises a fundamental question: should isotropy be enforced to achieve a better balance between stability and plasticity, and thereby mitigate catastrophic forgetting? In this paper, we investigate whether promoting feature-space isotropy can enhance representation quality in continual learning. Through experiments using contrastive continual learning techniques on CIFAR-10 and CIFAR-100 data, we find that isotropic regularization fails to improve, and can in fact degrade, model accuracy in continual settings. Our results highlight essential differences in feature geometry between centralized and continual learning, suggesting that isotropy, while beneficial in centralized setups, may not constitute an appropriate inductive bias for non-stationary learning scenarios. △ Less

Submitted 6 February, 2026; originally announced February 2026.

The Emerging Use of GenAI for UX Research in Software Development: Challenges and Opportunities

Authors: Heloisa Candello, Werner Geyer, Siya Kunde, Michael Muller, Daita Sarkar, Jessica He, Mariela Claudia Lanza, Carlos Rosemberg, Gord Davison, Lisa Pelletier

Abstract: The growing adoption of generative AI (GenAI) is reshaping how user experience (UX) research teams conduct qualitative research in software development, creating opportunities to streamline the production of qualitative insights. This paper presents findings from two user studies examining how current practices are challenged by GenAI and offering design implications for future AI assistance. Semi… ▽ More The growing adoption of generative AI (GenAI) is reshaping how user experience (UX) research teams conduct qualitative research in software development, creating opportunities to streamline the production of qualitative insights. This paper presents findings from two user studies examining how current practices are challenged by GenAI and offering design implications for future AI assistance. Semi-structured interviews with 21 UX researchers, product managers, and designers reveal challenges of aligning AI capabilities with the interpretive, collaborative nature of qualitative research and tensions between roles. UX researchers expressed limited trust in AI-generated results, while product managers often overestimated AI capabilities, amplifying organizational pressures to accelerate research within agile workflows. In a second study, we validated an AI analysis approach more closely aligned with human analysis processes to address trust issues bottoms-up. We outline interaction patterns and design guidelines for responsibly integrating AI into software development cycles. △ Less

Submitted 17 December, 2025; originally announced December 2025.

Comments: 46 pages, 7 figures

Directional strong coupling at the nanoscale between hyperbolic polaritons and organic molecules

Authors: Ana I. F. Tresguerres-Mata, Olga G. Matveeva, Christian Lanza, José Álvarez-Cuervo, Kirill V. Voronin, Francesco Calavalle, Garen Avedissian, Pablo Díaz-Núñez, Gonzalo Álvarez-Pérez, Aitana Tarazaga Martín-Luengo, Javier Taboada-Gutiérrez, Jiahua Duan, Javier Martín-Sánchez, Andrei Bylinkin, Rainer Hillenbrand, Artem Mishchenko, Luis E. Hueso, Valentyn S. Volkov, Alexey Y. Nikitin, Pablo Alonso-González

Abstract: Strong coupling (SC) is a fundamental concept in physics that describes extreme interactions between light and matter. Recent experiments have demonstrated SC at the nanometer scale, where strongly confined polaritons, rather than photons, couple to quantum emitters or molecular vibrations. Coupling with the latter is generally referred to as vibrational SC (VSC) and is of significant fundamental… ▽ More Strong coupling (SC) is a fundamental concept in physics that describes extreme interactions between light and matter. Recent experiments have demonstrated SC at the nanometer scale, where strongly confined polaritons, rather than photons, couple to quantum emitters or molecular vibrations. Coupling with the latter is generally referred to as vibrational SC (VSC) and is of significant fundamental and technological interest, as it can be an effective tool for modifying molecular properties. However, the implementation of VSC, especially at the nanoscale, depends on the development of tuning mechanisms that allow control over the coupling strength and, eventually, its directionality, opening the door for the selective coupling of specific molecular vibrations. Here we report the observation of directional VSC. Specifically, we show nanoscale images of propagating hyperbolic phonon polaritons (PhPs) coupled to pentacene molecules revealing that the fingerprint of VSC for propagating polaritons -- a marked anti-crossing in their dispersion at the vibrational resonance -- can be modulated as a function of the direction of propagation. In addition, we show that VSC can exhibit an optimal condition for thin molecular layers, characterized by a maximum coupling strength along one single direction. This phenomenon is understood by analysing the overlap of the polariton field with molecular layers of varying thicknesses. Apart from their fundamental importance, our findings promise novel applications for directional sensing or local directional control of chemical properties at the nanoscale. △ Less

Submitted 26 September, 2025; originally announced September 2025.

Journal ref: Nature Photonics (2025)

Symmetry extension by condensation defects in five-dimensional gauge theories

Authors: Matteo Bertolini, Lorenzo Di Pietro, Stefano C. Lanza, Pierluigi Niro, Antonio Santaniello

Abstract: We investigate the symmetry structure of five-dimensional Yang-Mills theories with $\mathfrak{su}(N)$ gauge algebra. These theories feature intertwined 0-, 1-, and 2-form symmetries, depending on the global variant one is considering. In the $SU(N)$ theory, there is a mixed 't Hooft anomaly between the instantonic 0-form symmetry and the electric 1-form symmetry. We show that in the $PSU(N)$ theor… ▽ More We investigate the symmetry structure of five-dimensional Yang-Mills theories with $\mathfrak{su}(N)$ gauge algebra. These theories feature intertwined 0-, 1-, and 2-form symmetries, depending on the global variant one is considering. In the $SU(N)$ theory, there is a mixed 't Hooft anomaly between the instantonic 0-form symmetry and the electric 1-form symmetry. We show that in the $PSU(N)$ theory this translates into a $\mathbb{Z}_N$ extension of the instantonic symmetry, generated by an invertible condensation defect of the magnetic 2-form symmetry. We identify the charged configurations as linked 't Hooft surfaces, while pointlike instanton operators remain insensitive to the extension. We generalize our analysis to the $SU(N)/\mathbb{Z}_k$ global form and show that similar results hold, embedded now in a 3-group structure for generic $k$. We then apply our findings to $SO(3)$ supersymmetric Yang-Mills theory. We determine the global form of the enhanced instantonic symmetry of its superconformal UV completion, showing that it arises through a similar symmetry extension mechanism from the parent $E_1$ theory, which is the UV completion of $SU(2)$ supersymmetric Yang-Mills theory. Finally, we recast our results in the language of the symmetry topological field theory. As a warm-up, we also analyze Maxwell theory, highlighting analogous features involving continuous symmetries and composite currents. △ Less

Submitted 20 February, 2026; v1 submitted 19 September, 2025; originally announced September 2025.

Comments: 59 pages, 4 figures, v2: typos corrected, references added, version accepted by JHEP

Visualization of topological shear polaritons in gypsum thin films

Authors: Pablo Díaz-Núñez, Christian Lanza, Ziwei Wang, Vasyl G. Kravets, Jiahua Duan, José Álvarez-Cuervo, Aitana Tarazaga Martín-Luengo, Alexander N. Grigorenko, Qian Yang, Alexander Paarmann, Joshua Caldwell, Pablo Alonso-González, Artem Mishchenko

Abstract: Low symmetry crystals have recently emerged as a platform for exploring novel light-matter interactions in the form of hyperbolic shear polaritons. These excitations exhibit unique optical properties such as frequency-dispersive optical axes and asymmetric light propagation and energy dissipation, which arise from the presence of non-orthogonal resonances. However, only non-vdW materials have been… ▽ More Low symmetry crystals have recently emerged as a platform for exploring novel light-matter interactions in the form of hyperbolic shear polaritons. These excitations exhibit unique optical properties such as frequency-dispersive optical axes and asymmetric light propagation and energy dissipation, which arise from the presence of non-orthogonal resonances. However, only non-vdW materials have been demonstrated to support hyperbolic shear polaritons, limiting their exotic properties and potential applications. Here we introduce for the first time novel shear phenomena in low symmetry crystal thin films by demonstrating the existence of elliptical and canalized shear phonon polaritons in gypsum, an exfoliable monoclinic sulphate mineral. Our results unveil a topological transition from hyperbolic shear to elliptical shear polaritons, passing through a canalization regime with strong field confinement. Importantly, we observe a significant slowdown of group velocity, reaching values as low as 0.0005c, highlighting the potential of gypsum for "slow light" applications and extreme light-matter interaction control. These findings expand the application scope of low-symmetry crystals with the benefits that an exfoliable material provides, such as stronger field confinement, tunability, and versatility for its incorporation in complex photonic devices that might unlock new optical phenomena at the nanoscale. △ Less

Submitted 31 January, 2025; originally announced January 2025.

Unveiling the Mechanism of Phonon-Polariton Damping in α-MoO_3

Authors: Javier Taboada-Gutiérrez, Yixi Zhou, Ana I. F. Tresguerres-Mata, Christian Lanza, Abel Martínez-Suárez, Gonzalo Álvarez-Pérez, Jiahua Duan, José Ignacio Martín, María Vélez, Iván Prieto, Adrien Bercher, Jérémie Teyssier, Ion Errea, Alexey Y. Nikitin, Javier Martín-Sánchez, Alexey B. Kuzmenko, Pablo Alonso-González

Abstract: Phonon polaritons (PhPs) (light coupled to lattice vibrations) in the highly anisotropic polar layered material molybdenum trioxide (α-MoO_3) are currently the focus of intense research efforts due to their extreme subwavelength field confinement, directional propagation and unprecedented low losses. Nevertheless, prior research has primarily concentrated on exploiting the squeezing and steering c… ▽ More Phonon polaritons (PhPs) (light coupled to lattice vibrations) in the highly anisotropic polar layered material molybdenum trioxide (α-MoO_3) are currently the focus of intense research efforts due to their extreme subwavelength field confinement, directional propagation and unprecedented low losses. Nevertheless, prior research has primarily concentrated on exploiting the squeezing and steering capabilities of α-MoO_3 PhPs, without inquiring much into the dominant microscopic mechanism that determines their long lifetimes, key for their implementation in nanophotonic applications. This study delves into the fundamental processes that govern PhP damping in α-MoO_3 by combining ab initio calculations with scattering-type scanning near-field optical microscopy (s-SNOM) and Fourier-transform infrared (FTIR) spectroscopy measurements across a broad temperature range (from 8 to 300 K). The remarkable agreement between our theoretical predictions and experimental observations allows us to identify third-order anharmonic phonon-phonon scattering as the main damping mechanism of α-MoO_3 PhPs. These findings shed light on the fundamental limits of low-loss PhPs, a crucial factor for assessing their implementation into nanophotonic devices. △ Less

Submitted 19 August, 2024; originally announced August 2024.

Comments: 24 pages, 4 figures

Canalization-based super-resolution imaging using a single van der Waals layer

Authors: Jiahua Duan, Aitana Tarazaga Martin-Luengo, Christian Lanza, Stefan Partel, Kirill Voronin, Ana Isabel F. Tresguerres-Mata, Gonzalo Álvarez-Pérez, Alexey Y. Nikitin, J. Martín-Sánchez, P. Alonso-González

Abstract: Canalization is an optical phenomenon that enables unidirectional propagation of light in a natural way, i.e., without the need for predefined waveguiding designs. Predicted years ago, it was recently demonstrated using highly confined phonon polaritons (PhPs) in twisted layers of the van der Waals (vdW) crystal alpha-MoO3, offering unprecedented possibilities for controlling light-matter interact… ▽ More Canalization is an optical phenomenon that enables unidirectional propagation of light in a natural way, i.e., without the need for predefined waveguiding designs. Predicted years ago, it was recently demonstrated using highly confined phonon polaritons (PhPs) in twisted layers of the van der Waals (vdW) crystal alpha-MoO3, offering unprecedented possibilities for controlling light-matter interactions at the nanoscale. However, despite this finding, applications based on polariton canalization have remained elusive so far, which can be explained by the complex sample fabrication of twisted stacks. In this work, we introduce a novel canalization phenomenon, arising in a single vdW thin layer (alpha-MoO3) when it is interfaced with a substrate exhibiting a given negative permittivity, that allows us to demonstrate a proof-of-concept application based on polariton canalization: super-resolution (up to ~λ0/220) nanoimaging. Importantly, we find that canalization-based imaging transcends conventional projection constraints, allowing the super-resolution images to be obtained at any desired location in the image plane. This versatility stems from the synergetic manipulation of three distinct parameters: incident frequency, rotation angle of the thin vdW layer, and thickness. These results provide valuable insights into the fundamental properties of canalization and constitute a seminal step towards multifaceted photonic applications, encompassing imaging, data transmission, and ultra-compact photonic integration. △ Less

Submitted 23 April, 2024; originally announced April 2024.

Comments: 11 pages, 3 figures

Unidirectional Ray Polaritons in Twisted Asymmetric Stacks

Authors: J. Álvarez-Cuervo, M. Obst, S. Dixit, G. Carini, A. I. F. Tresguerres-Mata, C. Lanza, E. Terán-García, G. Álvarez-Pérez, L. Álvarez-Tomillo, K. Diaz-Granados, R. Kowalski, A. S. Senerath, N. S. Mueller, L. Herrer, J. M. De Teresa, S. Wasserroth, J. M. Klopf, T. Beechem, M. Wolf, L. M. Eng, T. G. Folland, A. Tarazaga Martín-Luengo, J. Martín-Sánchez, S. C. Kehr, A. Y. Nikitin , et al. (3 additional authors not shown)

Abstract: The vast repository of van der Waals (vdW) materials supporting polaritons offers numerous possibilities to tailor electromagnetic waves at the nanoscale. The development of twistoptics - the modulation of the optical properties by twisting stacks of vdW materials - enables directional propagation of phonon polaritons (PhPs) along a single spatial direction, known as canalization. Here we demonstr… ▽ More The vast repository of van der Waals (vdW) materials supporting polaritons offers numerous possibilities to tailor electromagnetic waves at the nanoscale. The development of twistoptics - the modulation of the optical properties by twisting stacks of vdW materials - enables directional propagation of phonon polaritons (PhPs) along a single spatial direction, known as canalization. Here we demonstrate a complementary type of directional propagation of polaritons by reporting the visualization of unidirectional ray polaritons (URPs). They arise naturally in twisted hyperbolic stacks with very different thicknesses of their constituents, demonstrated for homostructures of $α$-MoO$_3$ and heterostructures of $α$-MoO$_3$ and $β$-Ga$_2$O$_3$. Importantly, their ray-like propagation, characterized by large momenta and constant phase, is tunable by both the twist angle and the illumination frequency. Apart from their fundamental importance, our findings introduce twisted asymmetric stacks as efficient platforms for nanoscale directional polariton propagation, opening the door for applications in nanoimaging, (bio)-sensing or polaritonic thermal management. △ Less

Submitted 7 January, 2025; v1 submitted 27 March, 2024; originally announced March 2024.

Comments: 15 pages, 5 figures

Journal ref: Nature Communications 15, 9042 (2024)

Multiple and spectrally robust photonic magic angles in reconfigurable α-MoO3 trilayers

Authors: J. Duan, G. Álvarez-Pérez, C. Lanza, A. I. F. Tresguerres-Mata, K. Voronin, N. Capote-Robayna, A. Tarazaga Martín-Luengo, J. Martín-Sánchez, V. S. Volkov, A. Y. Nikitin, P. Alonso-González

Abstract: The assembling of twisted stacks of van der Waals (vdW) materials had led to the discovery of a profusion of remarkable physical phenomena in recent years, as it provides a means to accurately control and harness electronic band structures. This has given birth to the so-called field of twistronics. An analogous concept has been developed for highly confined polaritons, or nanolight, in twisted bi… ▽ More The assembling of twisted stacks of van der Waals (vdW) materials had led to the discovery of a profusion of remarkable physical phenomena in recent years, as it provides a means to accurately control and harness electronic band structures. This has given birth to the so-called field of twistronics. An analogous concept has been developed for highly confined polaritons, or nanolight, in twisted bilayers of strongly anisotropic vdW materials, extending the field to the twistoptics realm. In this case, the emergence of a topological transition of the polaritonic dispersion at a given twist angle (photonic magic angle) results in the propagation of nanolight along one specific direction (canalization regime), holding promises for unprecedented control of the flow of energy at the nanoscale. However, there is a fundamental limitation in twistoptics that critically impedes such control: there is only one photonic magic angle (and thus canalization direction) in a twisted bilayer and it is fixed for each incident frequency. Here, we overcome this limitation by demonstrating the existence of multiple spectrally robust photonic magic angles in reconfigurable twisted vdW trilayers. As a result, we show that canalization of nanolight can be programmed at will along any desired in-plane direction in a single device, and, importantly, within broad spectral ranges of up to 70 cm-1. Our findings lay the foundation for robust and widely tunable twistoptics, opening the door for applications in nanophotonics where on-demand control of energy at the nanoscale is crucial, such as thermal management, nanoimaging or entanglement of quantum emitters. △ Less

Submitted 7 November, 2023; originally announced November 2023.

Comments: 16 pages, 3 figures

Journal ref: Nat. Mater. 22, 867-872 (2023)

Fundamentals of polaritons in strongly anisotropic thin crystal layers

Authors: Kirill V. Voronin, Gonzalo Álvarez-Pérez, Christian Lanza, Pablo Alonso-González, Alexey Y. Nikitin

Abstract: Polaritons in strongly anisotropic thin layers have recently captured the attention in nanophotonics because of their directional propagation at the nanoscale, which offers unique possibilities for nanooptical applications. However, exploiting the full potential of anisotropic polaritons requires a thorough understanding of their properties, including field confinement, energy and phase propagatio… ▽ More Polaritons in strongly anisotropic thin layers have recently captured the attention in nanophotonics because of their directional propagation at the nanoscale, which offers unique possibilities for nanooptical applications. However, exploiting the full potential of anisotropic polaritons requires a thorough understanding of their properties, including field confinement, energy and phase propagation direction and losses. Here we fill this critical gap by providing fundamental insights into the propagation of anisotropic polaritons in thin biaxial layers. In particular, we introduce a novel methodology that allows us to represent isofrequency curves of polaritons in strongly anisotropic materials considering that the real and imaginary parts of the wavevector are not parallel. In fact, we analytically show that the direction of the imaginary part of the wavevector is parallel to the group velocity, which can have different, even perpendicular or opposite, directions with respect to the phase velocity. This finding is crucial for understanding polaritonic phenomena in anisotropic media, yet it has so far been widely overlooked in the literature. Additionally, we introduce a criterion for classifying the polaritonic modes in biaxial layers into volume and surface categories, and analyze their dispersion, field structure, and losses. Finally, we discover the existence of anisotropic transverse electric modes, which can exhibit natural canalization. Taken together, our results shed light on hitherto unexplored areas of the theory of electromagnetic modes in thin biaxial layers. Although exemplified for van der Waals MoO3 layers, our findings are general for polaritons in other strongly anisotropic biaxial hyperbolic crystals. △ Less

Submitted 2 October, 2023; v1 submitted 22 September, 2023; originally announced September 2023.

Comments: 25 pages, 5 figures, including supplementary information

Dark matter search in a Beam-Dump eXperiment (BDX) at Jefferson Lab

Authors: BDX Collaboration, M. Battaglieri, A. Celentano, R. De Vita, E. Izaguirre, G. Krnjaic, E. Smith, S. Stepanyan, A. Bersani, E. Fanchini, S. Fegan, P. Musico, M. Osipenko, M. Ripani, E. Santopinto, M. Taiuti, P. Schuster, N. Toro, M. Dalton, A. Freyberger, F. -X. Girod, V. Kubarovsky, M. Ungaro, G. De Cataldo, R. De Leo , et al. (61 additional authors not shown)

Abstract: MeV-GeV dark matter (DM) is theoretically well motivated but remarkably unexplored. This Letter of Intent presents the MeV-GeV DM discovery potential for a 1 m$^3$ segmented plastic scintillator detector placed downstream of the beam-dump at one of the high intensity JLab experimental Halls, receiving up to 10$^{22}$ electrons-on-target (EOT) in a one-year period. This experiment (Beam-Dump eXperi… ▽ More MeV-GeV dark matter (DM) is theoretically well motivated but remarkably unexplored. This Letter of Intent presents the MeV-GeV DM discovery potential for a 1 m$^3$ segmented plastic scintillator detector placed downstream of the beam-dump at one of the high intensity JLab experimental Halls, receiving up to 10$^{22}$ electrons-on-target (EOT) in a one-year period. This experiment (Beam-Dump eXperiment or BDX) is sensitive to DM-nucleon elastic scattering at the level of a thousand counts per year, with very low threshold recoil energies ($\sim$1 MeV), and limited only by reducible cosmogenic backgrounds. Sensitivity to DM-electron elastic scattering and/or inelastic DM would be below 10 counts per year after requiring all electromagnetic showers in the detector to exceed a few-hundred MeV, which dramatically reduces or altogether eliminates all backgrounds. Detailed Monte Carlo simulations are in progress to finalize the detector design and experimental set up. An existing 0.036 m$^3$ prototype based on the same technology will be used to validate simulations with background rate estimates, driving the necessary R$\&$D towards an optimized detector. The final detector design and experimental set up will be presented in a full proposal to be submitted to the next JLab PAC. A fully realized experiment would be sensitive to large regions of DM parameter space, exceeding the discovery potential of existing and planned experiments by two orders of magnitude in the MeV-GeV DM mass range. △ Less

Submitted 11 June, 2014; originally announced June 2014.

Comments: 28 pages, 17 figures, submitted to JLab PAC 42

Expression of Interest for a Novel Search for CP Violation in the Neutrino Sector: DAEdALUS

Authors: J. Alonso, F. T. Avignone, W. A. Barletta, R. Barlow, H. T. Baumgartner, A. Bernstein, E. Blucher, L. Bugel, L. Calabretta, L. Camilleri, R. Carr, J. M. Conrad, S. A. Dazeley, Z. Djurcic, A. de Gouvea, P. H. Fisher, C. M. Ignarra, B. J. P. Jones, C. L. Jones, G. Karagiorgi, T. Katori, S. E. Kopp, R. C. Lanza, W. A. Loinaz, P. McIntyre , et al. (20 additional authors not shown)

Abstract: DAEdALUS, a Decay-At-rest Experiment for delta_CP studies At the Laboratory for Underground Science, provides a new approach to the search for CP violation in the neutrino sector. The design utilizes low-cost, high-power proton accelerators under development for commercial uses. These provide neutrino beams with energy up to 52 MeV from pion and muon decay-at-rest. The experiment searches for anin… ▽ More DAEdALUS, a Decay-At-rest Experiment for delta_CP studies At the Laboratory for Underground Science, provides a new approach to the search for CP violation in the neutrino sector. The design utilizes low-cost, high-power proton accelerators under development for commercial uses. These provide neutrino beams with energy up to 52 MeV from pion and muon decay-at-rest. The experiment searches for aninu_mu to antinu_e at short baselines corresponding to the atmospheric Delta m^2 region. The antinu_e will be detected, via inverse beta decay, in the 300 kton fiducial-volume Gd-doped water Cherenkov neutrino detector proposed for the Deep Underground Science and Engineering Laboratory (DUSEL). DAEdALUS opens new opportunities for DUSEL. It provides a high-statistics, low-background alternative for CP violation searches which matches the capability of the conventional long-baseline neutrino experiment, LBNE. Because of the complementary designs, when DAEdALUS antineutrino data are combined with LBNE neutrino data, the sensitivity of the CP-violation search improves beyond any present proposals, including the proposal for Project X. Also, the availability of an on-site neutrino beam opens opportunities for additional physics, both for the presently planned DUSEL detectors and for new experiments at a future 300 ft campus. △ Less

Submitted 1 June, 2010; originally announced June 2010.

Comments: Submitted to the DUSEL Directorate