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LDMX -- The Light Dark Matter eXperiment
Authors:
Torsten Akesson,
Layan Alsaraya,
Stephen Appert,
Charles Bell,
Elizabeth Berzin,
Nikita Blinov,
Léo Borrel,
Cameron Bravo,
Liam Brennan,
Lene Kristian Bryngemark,
Pierfrancesco Butti,
Riccardo Catena,
Anthony Chavez,
Owen Colegrove,
Giulia Collura,
Patill Daghlian,
Filippo Delzanno,
E. Craig Dukes,
Valentina Dutta,
Bertrand Echenard,
Ralf Ehrlich,
Thomas Eichlersmith,
Jonathan Eisch,
Einar Elén,
Eric Fernandez
, et al. (94 additional authors not shown)
Abstract:
The Light Dark Matter eXperiment (LDMX) is an electron fixed-target experiment optimized to search for sub-GeV dark matter production through the missing momentum signature. LDMX is designed to operate in End Station A at SLAC, using an 8 GeV electron beam accelerated alongside the LCLS-II drive beam. The design of the apparatus is strongly motivated by the performance requirements of a high-rate…
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The Light Dark Matter eXperiment (LDMX) is an electron fixed-target experiment optimized to search for sub-GeV dark matter production through the missing momentum signature. LDMX is designed to operate in End Station A at SLAC, using an 8 GeV electron beam accelerated alongside the LCLS-II drive beam. The design of the apparatus is strongly motivated by the performance requirements of a high-rate missing momentum search and leverages detector technologies and designs from other experiments along with existing facilities at SLAC. LDMX will improve on previous results by up to three orders of magnitude, enabling broad sensitivity to dark sector scenarios including the dark matter interaction strengths motivated by freeze-out of MeV-GeV mass dark matter to the observed relic abundance. With hermetic forward coverage, LDMX also has sensitivity to visible signatures of dark sectors and provides a unique probe of electron-nuclear interactions important to interpreting data from accelerator-based neutrino experiments. This report encompasses the technical design of the LDMX Detector, its simulated performance, and the physics capabilities of the experiment.
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Submitted 2 October, 2025; v1 submitted 15 August, 2025;
originally announced August 2025.
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Search for $CP$-Violating Neutrino Nonstandard Interactions with the NOvA Experiment
Authors:
NOvA Collaboration,
M. A. Acero,
B. Acharya,
P. Adamson,
L. Aliaga,
N. Anfimov,
A. Antoshkin,
E. Arrieta-Diaz,
L. Asquith,
A. Aurisano,
A. Back,
N. Balashov,
P. Baldi,
B. A. Bambah,
A. Bat,
K. Bays,
R. Bernstein,
T. J. C. Bezerra,
V. Bhatnagar,
D. Bhattarai,
B. Bhuyan,
J. Bian,
A. C. Booth,
R. Bowles,
B. Brahma
, et al. (182 additional authors not shown)
Abstract:
This Letter reports a search for charge-parity ($CP$) symmetry violating nonstandard interactions (NSI) of neutrinos with matter using the NOvA Experiment, and examines their effects on the determination of the standard oscillation parameters. Data from $ν_μ(\barν_μ)\rightarrowν_μ(\barν_μ)$ and $ν_μ(\barν_μ)\rightarrowν_{e}(\barν_{e})$ oscillation channels are used to measure the effect of the NSI…
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This Letter reports a search for charge-parity ($CP$) symmetry violating nonstandard interactions (NSI) of neutrinos with matter using the NOvA Experiment, and examines their effects on the determination of the standard oscillation parameters. Data from $ν_μ(\barν_μ)\rightarrowν_μ(\barν_μ)$ and $ν_μ(\barν_μ)\rightarrowν_{e}(\barν_{e})$ oscillation channels are used to measure the effect of the NSI parameters $\varepsilon_{eμ}$ and $\varepsilon_{eτ}$. With 90% CL the magnitudes of the NSI couplings are constrained to be $|\varepsilon_{eμ}| \, \lesssim 0.3$ and $|\varepsilon_{eτ}| \, \lesssim 0.4$. A degeneracy at $|\varepsilon_{eτ}| \, \approx 1.8$ is reported, and we observe that the presence of NSI limits sensitivity to the standard $CP$ phase $δ_{\tiny\text{CP}}$.
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Submitted 27 November, 2024; v1 submitted 11 March, 2024;
originally announced March 2024.
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Expanding neutrino oscillation parameter measurements in NOvA using a Bayesian approach
Authors:
NOvA Collaboration,
M. A. Acero,
B. Acharya,
P. Adamson,
N. Anfimov,
A. Antoshkin,
E. Arrieta-Diaz,
L. Asquith,
A. Aurisano,
A. Back,
N. Balashov,
P. Baldi,
B. A. Bambah,
A. Bat,
K. Bays,
R. Bernstein,
T. J. C. Bezerra,
V. Bhatnagar,
D. Bhattarai,
B. Bhuyan,
J. Bian,
A. C. Booth,
R. Bowles,
B. Brahma,
C. Bromberg
, et al. (174 additional authors not shown)
Abstract:
NOvA is a long-baseline neutrino oscillation experiment that measures oscillations in charged-current $ν_μ \rightarrow ν_μ$ (disappearance) and $ν_μ \rightarrow ν_{e}$ (appearance) channels, and their antineutrino counterparts, using neutrinos of energies around 2 GeV over a distance of 810 km. In this work we reanalyze the dataset first examined in our previous paper [Phys. Rev. D 106, 032004 (20…
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NOvA is a long-baseline neutrino oscillation experiment that measures oscillations in charged-current $ν_μ \rightarrow ν_μ$ (disappearance) and $ν_μ \rightarrow ν_{e}$ (appearance) channels, and their antineutrino counterparts, using neutrinos of energies around 2 GeV over a distance of 810 km. In this work we reanalyze the dataset first examined in our previous paper [Phys. Rev. D 106, 032004 (2022)] using an alternative statistical approach based on Bayesian Markov Chain Monte Carlo. We measure oscillation parameters consistent with the previous results. We also extend our inferences to include the first NOvA measurements of the reactor mixing angle $θ_{13}$ and the Jarlskog invariant. We use these results to quantify the strength of our inferences about CP violation, as well as to examine the effects of constraints from short-baseline measurements of $θ_{13}$ using antineutrinos from nuclear reactors when making NOvA measurements of $θ_{23}$. Our long-baseline measurement of $θ_{13}$ is also shown to be consistent with the reactor measurements, supporting the general applicability and robustness of the PMNS framework for neutrino oscillations.
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Submitted 27 May, 2024; v1 submitted 13 November, 2023;
originally announced November 2023.
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Charged Leptons
Authors:
J. Albrecht,
M. Artuso,
K. Babu,
R. H. Bernstein,
T. Blum,
D. N. Brown,
B. C. K. Casey,
C. -h. Cheng,
V. Cirigliano,
A. Cohen,
A. Deshpande,
E. C. Dukes,
B. Echenard,
A. Gaponenko,
D. Glenzinski,
M. Gonzalez-Alonso,
F. Grancagnolo,
Y. Grossman,
R. C. Group,
R. Harnik,
D. G. Hitlin,
B. Kiburg,
K. Knoepfe,
K. Kumar,
G. Lim
, et al. (12 additional authors not shown)
Abstract:
This is the report of the Intensity Frontier Charged Lepton Working Group of the 2013 Community Summer Study "Snowmass on the Mississippi", summarizing the current status and future experimental opportunities in muon and tau lepton studies and their sensitivity to new physics. These include searches for charged lepton flavor violation, measurements of magnetic and electric dipole moments, and prec…
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This is the report of the Intensity Frontier Charged Lepton Working Group of the 2013 Community Summer Study "Snowmass on the Mississippi", summarizing the current status and future experimental opportunities in muon and tau lepton studies and their sensitivity to new physics. These include searches for charged lepton flavor violation, measurements of magnetic and electric dipole moments, and precision measurements of the decay spectrum and parity-violating asymmetries.
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Submitted 24 November, 2013; v1 submitted 20 November, 2013;
originally announced November 2013.