The LEGEND Collaboration is searching for neutrinoless double-beta (0νββ) decay by operating high-purity germanium detectors enriched in ^{76}Ge in a low-background liquid argon environment. Building on key technological innovations from the GERmanium Detector Array (GERDA) experiment and the MAJORANA DEMONSTRATOR experiment, LEGEND-200 has performed a first 0νββ decay search based on 61.0 kg yr of data. Over half of this exposure comes from our highest performing detectors, including newly developed inverted-coaxial detectors, and is characterized by an estimated background level of 0.5_{-0.2}^{+0.3}  cts/(keV ton yr) in the 0νββ decay signal region. A combined analysis of data from GERDA, the MAJORANA DEMONSTRATOR, and LEGEND-200, characterized by a 90% confidence level exclusion sensitivity of 2.8×10^{26}  yr on the half-life of 0νββ decay, reveals no evidence for a signal and sets a new observed lower limit at T_{1/2}^{0ν}>1.9×10^{26}  yr (90% confidence level). Assuming the decay is mediated by Majorana neutrinos, this corresponds to an upper limit on the effective Majorana mass in the range m_{ββ}<75-200  meV, depending on the adopted nuclear matrix element.

We present a search for neutrinoless double-beta (0νββ) decay of ^{136}Xe using the full KamLAND-Zen 800 dataset with 745 kg of enriched xenon, corresponding to an exposure of 2.1 ton yr of ^{136}Xe. This updated search benefits from a more than twofold increase in exposure, recovery of photo-sensor gain, and reduced background from muon-induced spallation of xenon. Combining with the search in the previous KamLAND-Zen phase, we obtain a lower limit for the 0νββ decay halflife of T_{1/2}^{0ν}>3.8×10^{26}  yr at 90% CL, a factor of 1.7 improvement over the previous limit. The corresponding upper limits on the effective Majorana neutrino mass are in the range 28-122 meV using phenomenological nuclear matrix element calculations.

Ge-76 can beta beta decay into three possible excited states of Se-76, with the emission of two or, if the neutrino is Majorana, zero neutrinos. None of these six transitions have yet been observed. The MAJORANA DEMONSTRATOR was designed to study beta beta decay of Ge-76 using a low background array of high purity germanium detectors. With 98.2 kg-y of isotopic exposure, the Demonstrator sets the strongest half-life limits to date for all six transition modes. For 2 nu beta beta to the 0(1)(+) state of Se-76, this search has begun to probe for the first time half-life values predicted using modern many-body nuclear theory techniques, setting a limit of T-1/2 > 1.5 x 10(24) y (90% CL).

Ge76 can ββ decay into three possible excited states of Se76, with the emission of two or, if the neutrino is Majorana, zero neutrinos. None of these six transitions have yet been observed. The was designed to study ββ decay of Ge76 using a low background array of high purity germanium detectors. With 98.2 kg-y of isotopic exposure, the emonstrator sets the strongest half-life limits to date for all six transition modes. For 2νββ to the 01+ state of Se76, this search has begun to probe for the first time half-life values predicted using modern many-body nuclear theory techniques, setting a limit of T1/2>1.5×1024 y (90% CL). Published by the American Physical Society 2025

The MAJORANA DEMONSTRATOR was an ultra-low-background experiment designed for neutrinoless double-beta decay (0v beta beta) investigation in Ge-76. Located at the Sanford Underground Research Facility in Lead, South Dakota, the DEMONSTRATOR utilized modular high-purity Ge detector arrays within shielded vacuum cryostats, operating deep underground. The arrays, with a capacity of up to 40.4 kg (27.2 kg enriched to similar to 88% in Ge-76), have accumulated the full data set, totaling 64.5 kg yr of enriched active exposure and 27.4 kg yr of exposure for natural detectors. Our updated search improves previously explored three-nucleon decay modes in Ge isotopes, setting new partial lifetime limits of 1.83 x 10(26) yr (90% confidence level) for Ge-76(ppp) -> Cu-73 e(+)pi(+)pi(+) and Ge-76(ppn) -> Zn-73 e(+)pi(+). The partial lifetime limit for the fully inclusive triproton decay mode of Ge-76 is found to be 2.1 x 10(25) yr. Furthermore, we have updated limits for corresponding multinucleon decays.

The electron antineutrino flux limits are presented for the brightest gamma-ray burst (GRB) of all time, GRB221009A, over a range of 1.8–200 MeV using the Kamioka Liquid Scintillator Antineutrino Detector. Using multiple time windows ranging from minutes to days surrounding the event to search for electron antineutrinos coincident with the GRB, we set an upper limit on the flux under the assumption of several power-law neutrino source spectra, with power-law indices ranging from 1.5 to 3 in steps of 0.5. No excess was observed in any time windows ranging from seconds to days around the event trigger time T _0 . For a power-law index of 2 and a time window of T _0 ± 500 s, a flux upper limit of 2.34 × 10 ^9 cm ^−2 was calculated. The limits are compared to the results presented by IceCube.

We report the first detection of coherent elastic neutrino-nucleus scattering (CEvNS) on germanium, measured at the Spallation Neutron Source at Oak Ridge National Laboratory. The Ge-Mini detector of the COHERENT collaboration employs large-mass, low-noise, high-purity germanium spectrometers, enabling excellent energy resolution, and an analysis threshold of 1.5 keV electron-equivalent ionization energy. We observe a on-beam excess of 20.6$_{+7.1}^{-6.3}$ counts with a total exposure of 10.22 GWhkg and we reject the no-CEvNS hypothesis with 3.9 sigma significance. The result agrees with the predicted standard model of particle physics signal rate within 2 sigma.

High-momentum two-particle correlations are a useful tool for studying jet-quenching effects in the quark-gluon plasma. Angular correlations between neutral-pion triggers and charged hadrons with transverse momenta in the range 4–12 GeV/c and 0.5–7 GeV/c, respectively, have been measured by the PHENIX experiment in 2014 for Au+Au collisions at √(s__NN)=200 GeV. Suppression is observed in the yield of high-momentum jet fragments opposite the trigger particle, which indicates jet suppression stemming from in-medium partonic energy loss, while enhancement is observed for low-momentum particles. The ratio and differences between the yield in Au+Au collisions and p+p collisions, I_AA and Δ_AA, as a function of the trigger-hadron azimuthal separation, Δϕ, are measured for the first time at the Relativistic Heavy Ion Collider. These results better quantify how the yield of low-p_T associated hadrons is enhanced at wide angle, which is crucial for studying energy loss as well as medium-response effects.

The PHENIX experiment measured the centrality dependence of two-pion Bose-Einstein correlation functions in root sNN = 200 GeV Au + Au collisions at the Relativistic Heavy Ion Collider at Brookhaven National Laboratory. The data are well represented by Levy-stable source distributions. The extracted source parameters are the correlation-strength parameter lambda, the Levy index of stability a, and the Levy-scale parameter R as a function of transverse mass m(T) and centrality. The lambda(m(T)) parameter is constant at larger values of m(T), but decreases as m(T) decreases. The Levy-scale parameter R(m(T)) decreases with mT and exhibits proportionality to the length scale of the nuclear overlap region. The Levy exponent alpha(m(T)) is independent of m(T) within uncertainties in each investigated centrality bin, but shows a clear centrality dependence. At all centralities, the Levy exponent a is significantly different from that of Gaussian ( alpha= 2) or Cauchy ( alpha = 1) source distributions. Comparisons to the predictions of Monte-Carlo simulations of resonance-decay chains show that, in all but the most peripheral centrality class (50%-60%), the obtained results are inconsistent with the measurements, unless a significant reduction of the in-medium mass of the eta meson is included. In each centrality class, the best value of the in-medium eta mass is compared to the mass of the. meson, as well as to several theoretical predictions that consider restoration of U-A(1) symmetry in hot hadronic matter.

Preceding a core-collapse supernova (CCSN), various processes produce an increasing amount of neutrinos of all flavors characterized by mounting energies from the interior of massive stars. Among them, the electron antineutrinos are potentially detectable by terrestrial neutrino experiments such as KamLAND and Super-Kamiokande (SK) via inverse beta decay interactions. Once these pre-supernova (pre-SN) neutrinos are observed, an early warning of the upcoming CCSN can be provided. In light of this, KamLAND and SK, both located in the Kamioka mine in Japan, have been monitoring pre-SN neutrinos since 2015 and 2021, respectively. Recently, we performed a joint study between KamLAND and SK on pre-SN neutrino detection. A pre-SN alert system combining the KamLAND detector and the SK detector was developed and put into operation, which can provide a supernova alert to the astrophysics community. Fully leveraging the complementary properties of these two detectors, the combined alert is expected to resolve a pre-SN neutrino signal from a 15 M-circle dot star within 510 pc of the Earth at a significance level corresponding to a false alarm rate of no more than 1 per century. For a Betelgeuse-like model with optimistic parameters, it can provide early warnings up to 12 hr in advance.

With excellent energy resolution and ultralow-level radiogenic backgrounds, the high-purity germanium detectors in the Majorana Demonstrator enable searches for several classes of exotic dark matter (DM) models. In this work, we report new experimental limits on keV-scale sterile neutrino DM via the transition magnetic moment from conversion to active neutrinos ν_{s}→ν_{a}. We report new limits on fermionic dark matter absorption (χ+A→ν+A) and sub-GeV DM-nucleus 3→2 scattering (χ+χ+A→ϕ+A), and new exclusion limits for bosonic dark matter (axionlike particles and dark photons). These searches utilize the (1-100)-keV low-energy region of a 37.5-kg y exposure collected by the Demonstrator between May 2016 and November 2019 using a set of ^{76}Ge-enriched detectors whose surface exposure time was carefully controlled, resulting in extremely low levels of cosmogenic activation.

Charge conservation and the Pauli exclusion principle result from fundamental symmetries in the standard model of particle physics, and are typically taken as axiomatic. High-precision tests for small violations of these symmetries could point to new physics. Here we consider three models for violation of these processes, which would produce detectable ionization in the high-purity germanium detectors of the MAJORANA DEMONSTRATOR experiment. Using a 37.5 kg yr exposure, we report a lower limit on the electron mean lifetime, improving the previous best limit for the e ->nu(e)nu(e)(sic)nu(e) decay channel by more than an order of magnitude. We also present searches for two types of violation of the Pauli exclusion principle, setting limits on the probability of an electron to be found in a symmetric quantum state.

We consider the potential for a 10-kg undoped cryogenic CsI detector operating at the Spallation Neutron Source to measure coherent elastic neutrino-nucleus scattering and its sensitivity to discover new physics beyond the standard model. Through a combination of increased event rate, lower threshold, and good timing resolution, such a detector would significantly improve on past measurements. We considered tests of several beyond-the-standard-model scenarios such as neutrino non-standard interactions and accelerator-produced dark matter. This detector's performance was also studied for relevant questions in nuclear physics and neutrino astronomy, namely the weak charge distribution of CsI nuclei and detection of neutrinos from a core-collapse supernova.

The background index (BI) is an important quantity to project and calculate the half-life sensitivity of neutrinoless double-beta decay (0 nu beta beta) experiments. An analysis framework is presented to calculate the BI using the specific activities, masses, and simulated efficiencies of an experiments components as distributions. This Bayesian framework includes a unified approach to combine specific activities from assay. Monte Carlo uncertainty propagation is used to build a BI distribution from the specific activity, mass, and efficiency distributions. This method is applied to the MAJORANA DEMONSTRATOR, which deployed arrays of high-purity Ge detectors enriched in Ge-76 to search for 0 nu beta beta. The original assay-based projection is requantified in the new framework, using the as-built geometry of the DEMONSTRATOR and additional assay information. While 47% higher than the original projection, the resulting BI of [8.95 +/- 0.36] x 10(-4) cts/(keV kg yr) from the Th-232 and U-238 decay chains does not account for the higher-than-expected BI observed by the DEMONSTRATOR. This method enables us to demonstrate the statistical incompatibility between the DEMONSTRATOR's observed background and the assay results.

The COHERENT Collaboration searched for scalar dark matter particles produced at the Spallation Neutron Source with masses between 1 and 220  MeV/c^{2} using a CsI[Na] scintillation detector sensitive to nuclear recoils above 9  keV_{nr}. No evidence for dark matter is found and we thus place limits on allowed parameter space. With this low-threshold detector, we are sensitive to coherent elastic scattering between dark matter and nuclei. The cross section for this process is orders of magnitude higher than for other processes historically used for accelerator-based direct-detection searches so that our small, 14.6 kg detector significantly improves on past constraints. At peak sensitivity, we reject the flux consistent with the cosmologically observed dark-matter concentration for all coupling constants α_{D}<0.64, assuming a scalar dark-matter particle. We also calculate the sensitivity of future COHERENT detectors to dark-matter signals which will ambitiously test multiple dark-matter spin scenarios.

A. Adare,12 C. Aidala,39,45 N. N. Ajitanand,63,* Y. Akiba,57,58,† R. Akimoto,11 J. Alexander,63 M. Alfred,24 H. Al-Ta’ani,52 A. Angerami,13 K. Aoki,32,57 N. Apadula,29,64 Y. Aramaki,11,57 H. Asano,35,57 E. C. Aschenauer,7 E. T. Atomssa,64 T. C. Awes,54 B. Azmoun,7 V. Babintsev,25 A. Bagoly,17 M. Bai,6 B. Bannier,64 K. N. Barish,8 B. Bassalleck,51 S. Bathe,5,58 V. Baublis,56 S. Baumgart,57 A. Bazilevsky,7 R. Belmont,12,69 A. Berdnikov,60 Y. Berdnikov,60 D. S. Blau,34,50 M. Boer,39 J. S. Bok,51,52,72 K. Boyle,58 M. L. Brooks,39 J. Bryslawskyj,5,8 H. Buesching,7 V. Bumazhnov,25 S. Butsyk,51 S. Campbell,13,64 V. Canoa Roman,64 P. Castera,64 C.-H. Chen,58,64 C. Y. Chi,13 M. Chiu,7 I. J. Choi,26 J. B. Choi,10,* S. Choi,62 R. K. Choudhury,4 P. Christiansen,41 T. Chujo,68 O. Chvala,8 V. Cianciolo,54 Z. Citron,64,70 B. A. Cole,13 M. Connors,21,58,64 M. Csanád,17 T. Csörgő,18,71 S. Dairaku,35,57 T. W. Danley,53 A. Datta,44 M. S. Daugherity,1 G. David,7,64 K. DeBlasio,51 K. Dehmelt,64 A. Denisov,25 A. Deshpande,58,64 E. J. Desmond,7 K. V. Dharmawardane,52 O. Dietzsch,61 L. Ding,29 A. Dion,29,64 J. H. Do,72 M. Donadelli,61 L. D’Orazio,43 O. Drapier,36 A. Drees,64 K. A. Drees,6 J. M. Durham,39,64 A. Durum,25 S. Edwards,6 Y. V. Efremenko,54 T. Engelmore,13 A. Enokizono,54,57,59 S. Esumi,68 K. O. Eyser,7,8 B. Fadem,46 W. Fan,64 N. Feege,64 D. E. Fields,51 M. Finger,9 M. Finger, Jr.,9 F. Fleuret,36 S. L. Fokin,34 J. E. Frantz,53 A. Franz,7 A. D. Frawley,20 Y. Fukao,57 Y. Fukuda,68 T. Fusayasu,48 K. Gainey,1 C. Gal,64 P. Gallus,14 P. Garg,3,64 A. Garishvili,66 I. Garishvili,38 H. Ge,64 A. Glenn,38 X. Gong,63 M. Gonin,36 Y. Goto,57,58 R. Granier de Cassagnac,36 N. Grau,2 S. V. Greene,69 M. Grosse Perdekamp,26 T. Gunji,11 L. Guo,39 H.-Å. Gustafsson,41,* T. Hachiya,57,58 J. S. Haggerty,7 K. I. Hahn,19 H. Hamagaki,11 S. Y. Han,19 J. Hanks,13,64 S. Hasegawa,30 T. O. S. Haseler,21 K. Hashimoto,57,59 E. Haslum,41 R. Hayano,11 X. He,21 T. K. Hemmick,64 T. Hester,8 J. C. Hill,29 K. Hill,12 A. Hodges,21 R. S. Hollis,8 K. Homma,23 B. Hong,33 T. Horaguchi,68 Y. Hori,11 T. Hoshino,23 N. Hotvedt,29 J. Huang,7 S. Huang,69 T. Ichihara,57,58 H. Iinuma,32 Y. Ikeda,57,68 J. Imrek,16 M. Inaba,68 A. Iordanova,8 D. Isenhower,1 M. Issah,69 D. Ivanishchev,56 B. V. Jacak,64 M. Javani,21 Z. Ji,64 J. Jia,7,63 X. Jiang,39 B. M. Johnson,7,21 K. S. Joo,47 V. Jorjadze,64 D. Jouan,55 D. S. Jumper,26 J. Kamin,64 S. Kaneti,64 B. H. Kang,22 J. H. Kang,72 J. S. Kang,22 J. Kapustinsky,39 K. Karatsu,35,57 S. Karthas,64 M. Kasai,57,59 G. Kasza,17,18 D. Kawall,44,58 A. V. Kazantsev,34 T. Kempel,29 V. Khachatryan,64 A. Khanzadeev,56 K. M. Kijima,23 B. I. Kim,33 C. Kim,8,33 D. J. Kim,31 E.-J. Kim,10 H. J. Kim,72 K.-B. Kim,10 M. Kim,62 M. H. Kim,33 Y.-J. Kim,26 Y. K. Kim,22 D. Kincses,17 E. Kinney,12 Á. Kiss,17 E. Kistenev,7 J. Klatsky,20 D. Kleinjan,8 P. Kline,64 T. Koblesky,12 Y. Komatsu,11,32 B. Komkov,56 J. Koster,26 D. Kotchetkov,53 D. Kotov,56,60 A. Král,14 F. Krizek,31 S. Kudo,68 G. J. Kunde,39 B. Kurgyis,17 K. Kurita,57,59 M. Kurosawa,57,58 Y. Kwon,72 G. S. Kyle,52 R. Lacey,63 Y. S. Lai,13 J. G. Lajoie,29 A. Lebedev,29 B. Lee,22 D. M. Lee,39 J. Lee,19,65 K. B. Lee,33 K. S. Lee,33 S. H. Lee,29,64 S. R. Lee,10 M. J. Leitch,39 M. A. L. Leite,61 M. Leitgab,26 Y. H. Leung,64 B. Lewis,64 N. A. Lewis,45 X. Li,39 S. H. Lim,39,72 L. A. Linden Levy,12 M. X. Liu,39 S. Lökös,17,18 B. Love,69 D. Lynch,7 C. F. Maguire,69 Y. I. Makdisi,6 M. Makek,70,73 A. Manion,64 V. I. Manko,34 E. Mannel,7,13 H. Masuda,59 S. Masumoto,11,32 M. McCumber,12,39 P. L. McGaughey,39 D. McGlinchey,12,20,39 C. McKinney,26 M. Mendoza,8 B. Meredith,26 W. J. Metzger,18 Y. Miake,68 T. Mibe,32 A. C. Mignerey,43 D. E. Mihalik,64 A. Milov,70 D. K. Mishra,4 J. T. Mitchell,7 G. Mitsuka,58 Y. Miyachi,57,67 S. Miyasaka,57,67 A. K. Mohanty,4 S. Mohapatra,63 H. J. Moon,47 T. Moon,72 D. P. Morrison,7 S. I. Morrow,69 S. Motschwiller,46 T. V. Moukhanova,34 T. Murakami,35,57 J. Murata,57,59 A. Mwai,63 T. Nagae,35 K. Nagai,67 S. Nagamiya,32,57 K. Nagashima,23 J. L. Nagle,12 M. I. Nagy,17,71 I. Nakagawa,57,58 H. Nakagomi,57,68 Y. Nakamiya,23 K. R. Nakamura,35,57 T. Nakamura,57 K. Nakano,57,67 C. Nattrass,66 A. Nederlof,46 M. Nihashi,23,57 R. Nouicer,7,58 T. Novák,18,71 N. Novitzky,31,64 A. S. Nyanin,34 E. O’Brien,7 C. A. Ogilvie,29 K. Okada,58 J. D. Orjuela Koop,12 J. D. Osborn,45 A. Oskarsson,41 M. Ouchida,23,57 K. Ozawa,11,32,68 R. Pak,7 V. Pantuev,27 V. Papavassiliou,52 B. H. Park,22 I. H. Park,19,65 J. S. Park,62 S. Park,57,62,64 S. K. Park,33 S. F. Pate,52 L. Patel,21 M. Patel,29 H. Pei,29 J.-C. Peng,26 W. Peng,69 H. Pereira,15 D. V. Perepelitsa,7,12,13 G. D. N. Perera,52 D.Yu. Peressounko,34 C. E. PerezLara,64 R. Petti,7,64 C. Pinkenburg,7 R. P. Pisani,7 M. Proissl,64 A. Pun,53 M. L. Purschke,7 H. Qu,1 P. V. Radzevich,60 J. Rak,31 I. Ravinovich,70 K. F. Read,54,66 D. Reynolds,63 V. Riabov,50,56 Y. Riabov,56,60 E. Richardson,43 D. Richford,5 T. Rinn,29 D. Roach,69 G. Roche,40,* S. D. Rolnick,8 M. Rosati,29 Z. Rowan,5 J. Runchey,29 B. Sahlmueller,64 N. Saito,32 T. Sakaguchi,7 H. Sako,30 V. Samsonov,50,56 M. Sano,68 M. Sarsour,21 K. Sato,68 S. Sato,30 S. Sawada,32 B. K. Schmoll,66 K. Sedgwick,8 R. Seidl,57,58 A. Sen,21,29,66 R. Seto,8 A. Sexton,43 D. Sharma,64,70 I. Shein,25 T.-A. Shibata,57,67 K. Shigaki,23 M. Shimomura,29,49,68 K. Shoji,35,57 P. Shukla,4 A. Sickles,7,26 C. L. Silva,29,39 D. Silvermyr,41,54 K. S. Sim,33 B. K. Singh,3 C. P. Singh,3 V. Singh,3 M. J. Skoby,45 M. Slunečka,9 R. A. Soltz,38 W. E. Sondheim,39 S. P. Sorensen,66 I. V. Sourikova,7 P. W. Stankus,54 E. Stenlund,41 M. Stepanov,44,* A. Ster,71 S. P. Stoll,7 T. Sugitate,23 A. Sukhanov,7 J. Sun,64 J. Sziklai,71 E. M. Takagui,61 A. Takahara,11 A Takeda,49 A. Taketani,57,58 Y. Tanaka,48 S. Taneja,64 K. Tanida,30,58,62 M. J. Tannenbaum,7 S. Tarafdar,3,69 A. Taranenko,50,63 G. Tarnai,16 E. Tennant,52 H. Themann,64 R. Tieulent,42 A. Timilsina,29 T. Todoroki,57,68 L. Tomášek,28 M. Tomášek,14,28 H. Torii,23 C. L. Towell,1 R. S. Towell,1 I. Tserruya,70 Y. Tsuchimoto,11 T. Tsuji,11 Y. Ueda,23 B. Ujvari,16 C. Vale,7 H. W. van Hecke,39 M. Vargyas,17,71 S. Vazquez-Carson,12 E. Vazquez-Zambrano,13 A. Veicht,13 J. Velkovska,69 R. Vértesi,71 M. Virius,14 A. Vossen,26 V. Vrba,14,28 E. Vznuzdaev,56 X. R. Wang,52,58 Z. Wang,5 D. Watanabe,23 K. Watanabe,68 Y. Watanabe,57,58 Y. S. Watanabe,11 F. Wei,29,52 R. Wei,63 S. N. White,7 D. Winter,13 S. Wolin,26 C. L. Woody,7 M. Wysocki,12,54 B. Xia,53 C. Xu,52 Q. Xu,69

Using an 185-kg NaI[Tl] array, COHERENT has measured the inclusive electron-neutrino charged-current cross section on ^{127}I with pion decay-at-rest neutrinos produced by the Spallation Neutron Source at Oak Ridge National Laboratory. Iodine is one the heaviest targets for which low-energy (≤50  MeV) inelastic neutrino-nucleus processes have been measured, and this is the first measurement of its inclusive cross section. After a five-year detector exposure, COHERENT reports a flux-averaged cross section for electron neutrinos of 9.2_{-1.8}^{+2.1}×10^{-40}  cm^{2}. This corresponds to a value that is ∼41% lower than predicted using the MARLEY event generator with a measured Gamow-Teller strength distribution. In addition, the observed visible spectrum from charged-current scattering on ^{127}I has been measured between 10 and 55 MeV, and the exclusive zero-neutron and one-or-more-neutron emission cross sections are measured to be 5.2_{-3.1}^{+3.4}×10^{-40} and 2.2_{-0.5}^{+0.4}×10^{-40}  cm^{2}, respectively.

Received 2 October 2023DOI:https://doi.org/10.1103/PhysRevC.108.049905©2023 American Physical SocietyPhysics Subject Headings (PhySH)Research AreasParticle correlations & fluctuationsQuark-gluon plasmaRelativistic heavy-ion collisionsPhysical SystemsBose-Einstein condensatesPionsNuclear Physics

Description of the data release 10.13139/OLCF/1969085 (https://doi.ccs.ornl.gov/ui/doi/426) from the measurements of the CsI[Na] response to low energy nuclear recoils by the COHERENT collaboration. The release corresponds to the results published in "D. Akimov et al 2022 JINST 17 P10034". We share the data in the form of raw ADC waveforms, provide benchmark values, and share plots to enhance the transparency and reproducibility of our results. This document describes the contents of the data release as well as guidance on the use of the data.

^{180m}Ta is a rare nuclear isomer whose decay has never been observed. Its remarkably long lifetime surpasses the half-lives of all other known β and electron capture decays due to the large K-spin differences and small energy differences between the isomeric and lower-energy states. Detecting its decay presents a significant experimental challenge but could shed light on neutrino-induced nucleosynthesis mechanisms, the nature of dark matter, and K-spin violation. For this study, we repurposed the Majorana Demonstrator, an experimental search for the neutrinoless double-beta decay of ^{76}Ge using an array of high-purity germanium detectors, to search for the decay of ^{180m}Ta. More than 17 kg, the largest amount of tantalum metal ever used for such a search, was installed within the ultralow-background detector array. In this Letter, we present results from the first year of Ta data taking and provide an updated limit for the ^{180m}Ta half-life on the different decay channels. With new limits up to 1.5×10^{19}  yr, we improved existing limits by 1-2 orders of magnitude which are the most sensitive searches for a single β and electron capture decay ever achieved. Over all channels, the decay can be excluded for T_{1/2}<0.29×10^{18}  yr.