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1. The MAJORANA DEMONSTRATOR experiment's construction, commissioning, and performance

Author

Abgrall, N., Aguayo, E., Arnquist, I. J., Avignone III, F. T., Barabash, A. S., Barton, C. J., Barton, P. J., Bertrand, F. E., Blalock, E., Bos, B., Boswell, M., Bradley, A. W., Brudanin, V., Burritt, T. H., Busch, M., Buuck, M., Byram, D., Caldwell, A. S., Caldwell, T. S., Chan, Y. -D., Christofferson, C. D., Chu, P. -H., Clark, M. L., Combs, D. C., Cuesta, C., Detwiler, J. A., Efremenko, Yu., Ejiri, H., Elliott, S. R., Fast, J. E., Finnerty, P., Fraenkle, F. M., Fuad, N., Fuller, E., Gilliss, T., Giovanetti, G. K., Goett, J., Green, M. P., Gruszko, J., Guinn, I. S., Guiseppe, V. E., Harper, G. C., Haufe, C. R., Henning, R., Aguilar, D. Hervas, Hoppe, E. W., Hostiuc, A., Howe, M. A., Jasinski, B. R., Keeter, K. J., Kidd, M. F., Kim, I., Kouzes, R. T., LaFerriere, B. D., Lannen V, T. E., Li, A., Loach, J. C., Lopez, A. M., Lopez-Castano, J. M., MacMullin, J., MacMullin, S., Martin, E. L., Martin, R. D., Massarczyk, R., Meijer, S. J., Merriman, J. H., Mertens, S., Miley, H. S., Myslik, J., Oli, T. K., Orrell, J. L., O'Shaughnessy, C., Othman, G., Overman, N. R., Peterson, D., Pettus, W., Poon, A. W. P., Radford, D. C., Rager, J., Reine, A. L., Rielage, K., Robertson, R. G. H., Rodriguez, L., Ruof, N. W., Salazar, H., Schaper, D. C., Schleich, S. J., Shanks, B., Shirchenko, M., Snavely, K. J., Snyder, N., Soin, A., Steele, D., Suriano, A. M., Swift, G., Trimble, D. Tedeschi J. E., Turqueti, M., Van Wechel, T. D., Varner, R. L., Vasilyev, S., Vorren, K., Watkins, S. L., White, B. R., Wilkerson, J. F., Wiseman, C., Xu, W., Yaver, H., Yu, C. -H., Yumatov, V. I., Zhitnikov, I., and Zhu, B. X.

Subjects
Physics - Instrumentation and Detectors, Nuclear Experiment
Abstract

Background: The MAJORANA DEMONSTRATOR , a modular array of isotopically enriched high-purity germanium (HPGe) detectors, was constructed to demonstrate backgrounds low enough to justify building a tonne-scale experiment to search for the neutrinoless double-beta decay ($\beta\beta(0\nu)$) of $^{76}\mathrm{Ge}$. Purpose: This paper presents a description of the instrument, its commissioning, and operations. It covers the electroforming, underground infrastructure, enrichment, detector fabrication, low-background and construction techniques, electronics, data acquisition, databases, and data processing of the MAJORANA DEMONSTRATOR. Method: The MAJORANA DEMONSTRATOR operated inside an ultra-low radioactivity passive shield at the 4850-foot~level of the Sanford Underground Research Facility (SURF) from 2015-2021. Results and Conclusions: The MAJORANA DEMONSTRATOR achieved the best energy resolution and second-best background level of any $\beta\beta(0\nu)$ search. This enabled it to achieve an ultimate half-life limit on $\beta\beta(0\nu)$ in $^{76}\mathrm{Ge}$ of $8.3\times 10^{25}$~yr (90\% C.L.) and perform a rich set of searches for other physics beyond the Standard Model., Comment: 72 pages

Published
2025

2. Rare multi-nucleon decays with the full data sets of the Majorana Demonstrator

Author

Arnquist, I. J., Avignone III, F. T., Barabash, A. S., Blalock, E., Bos, B., Busch, M., Chan, Y. -D., Chapman, J. R., Christofferson, C. D., Chu, P. -H., Cuesta, C., Detwiler, J. A., Efremenko, Yu., Ejiri, H., Elliott, S. R., Fuad, N., Giovanetti, G. K., Green, M. P., Gruszko, J., Guinn, I. S., Guiseppe, V. E., Henning, R., Hoppe, E. W., Kouzes, R. T., Li, A., Massarczyk, R., Meijer, S. J., Paudel, L. S., Pettus, W., Poon, A. W. P., Radford, D. C., Reine, A. L., Rielage, K., Schaper, D. C., Schleich, S. J., Tedeschi, D., Varner, R. L., Vasilyev, S., Watkins, S. L., Wilkerson, J. F., Wiseman, C., and Yu, C. -H.

Subjects
Nuclear Experiment
Abstract

The Majorana Demonstrator was an ultra-low-background experiment designed for neutrinoless double-beta decay ($0\nu\beta\beta$) investigation in $^{76}$Ge. 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 $\sim 88\%$ in $^{76}$Ge), 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 half-life limits of $1.27\times10^{26}$ years (90\% confidence level) for $^{76}$Ge($ppp$) $\rightarrow$ $^{73}$Cu e$^+\pi^+\pi^+$ and $^{76}$Ge($ppn$) $\rightarrow$ $^{73}$Zn e$^+\pi^+$. The half-life limit for the invisible tri-proton decay mode of $^{76}$Ge is found to be $1.4\times10^{25}$ yr. Furthermore, we have updated limits for corresponding multi-nucleon decays.

Published
2024

3. Final Results of the MAJORANA DEMONSTRATOR's Search for Double-Beta Decay of $^{76}$Ge to Excited States of $^{76}$Se

Author

Arnquist, I. J., Avignone III, F. T., Barabash, A. S., Blalock, E., Bos, B., Busch, M., Chan, Y. -D., Chapman, J. R., Christofferson, C. D., Chu, P. -H., Cuesta, C., Detwiler, J. A., Efremenko, Yu., Ejiri, H., Elliott, S. R., Fuad, N., Giovanetti, G. K., Green, M. P., Gruszko, J., Guinn, I. S., Guiseppe, V. E., Haufe, C. R., Henning, R., Aguilar, D. Hervas, Hoppe, E. W., Kim, I., Kouzes, R. T., Lannen V, T. E., Li, A., Massarczyk, R., Meijer, S. J., Oli, T. K., Paudel, L. S., Pettus, W., Poon, A. W. P., Radford, D. C., Reine, A. L., Rielage, K., Schaper, D. C., Schleich, S. J., Tedeschi, D., Varner, R. L., Vasilyev, S., Watkins, S. L., Wilkerson, J. F., Wiseman, C., Yu, C. -H., and Zhu, B. X.

Subjects
Nuclear Experiment
Abstract

$^{76}$Ge can $\beta\beta$ decay into three possible excited states of $^{76}$Se, 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 $^{76}$Ge 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 $^{76}$Se, 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 $T_{1/2}>1.5\times10^{24}$ y (90% CL)., Comment: 8 pages, 3 figures

Published
2024

4. An assay-based background projection for the MAJORANA DEMONSTRATOR using Monte Carlo Uncertainty Propagation

Author

Arnquist, I. J., Avignone III, F. T., Barabash, A. S., Barton, C. J., Bhimani, K. H., Blalock, E., Bos, B., Busch, M., Caldwell, T. S., Chan, Y. -D., Christofferson, C. D., Chu, P. -H., Clark, M. L., Cuesta, C., Detwiler, J. A., Efremenko, Yu., Ejiri, H., Elliott, S. R., Fuad, N., Giovanetti, G. K., Green, M. P., Gruszko, J., Guinn, I. S., Guiseppe, V. E., Haufe, C. R., Henning, R., Aguilar, D. Hervas, Hoppe, E. W., Hostiuc, A., Kidd, M. F., Kim, I., Kouzes, R. T., Lannen V, T. E., Li, A., López-Castaño, J. M., Martin, R. D., Massarczyk, R., Meijer, S. J., Oli, T. K., Paudel, L. S., Pettus, W., Poon, A. W. P., Radford, D. C., Reine, A. L., Rielage, K., Ruof, N. W., Schaper, D. C., Schleich, S. J., Tedeschi, D., Varner, R. L., Vasilyev, S., Watkins, S. L., Wilkerson, J. F., Wiseman, C., Xu, W., and Yu, C. -H.

Subjects
Nuclear Experiment, Physics - Instrumentation and Detectors
Abstract

The background index is an important quantity which is used in projecting and calculating the half-life sensitivity of neutrinoless double-beta decay ($0\nu\beta\beta$) experiments. A novel analysis framework is presented to calculate the background index using the specific activities, masses and simulated efficiencies of an experiment's 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 background index distribution from the specific activity, mass and efficiency distributions. This analysis method is applied to the MAJORANA DEMONSTRATOR, which deployed arrays of high-purity Ge detectors enriched in $^{76}$Ge to search for $0\nu\beta\beta$. The framework projects a mean background index of $\left[8.95 \pm 0.36\right] \times 10^{-4}$cts/(keV kg yr) from $^{232}$Th and $^{238}$U in the DEMONSTRATOR's components., Comment: 9 pages, 3 figures

Published
2024

5. First detection of coherent elastic neutrino-nucleus scattering on germanium

Author

Adamski, S., Ahn, M., Barbeau, P. S., Belov, V., Bernardi, I., Bock, C., Bolozdynya, A., Bouabid, R., Browning, J., Cabrera-Palmer, B., Cedarblade-Jones, N., Rivera, J. Colón, Conley, E., da Silva, V., Daughhetee, J., Detwiler, J., Ding, K., Durand, M. R., Efremenko, Y., Elliott, S. R., Erlandson, A., Fabris, L., Galindo-Uribarri, A., Green, M. P., Hakenmüller, J., Heath, M. R., Hedges, S., Jeong, H., Johnson, B. A., Johnson, T., Jones, H., Khromov, A., Konovalov, A., Kozlova, E., Kumpan, A., Kyzylova, O., Lee, Y., Li, G., Li, L., Link, J. M., Liu, J., Luxnat, M., Major, A., Mann, K., Markoff, D. M., Mattingly, J., Moye, J., Mueller, P. E., Newby, J., Ogoi, N., O'Reilly, J., Parno, D. S., Pérez-Loureiro, D., Pershey, D., Prior, C. G., Queen, J., Rapp, R., Ray, H., Razuvaeva, O., Reyna, D., Rich, G. C., Rudik, D., Runge, J., Salvat, D. J., Sander, J., Scholberg, K., Shakirov, A., Simakov, G., Snow, W. M., Sosnovtsev, V., Stringer, M., Subedi, T., Suh, B., Sur, B., Tayloe, R., Tellez-Giron-Flores, K., Tsai, Y. -T., van Nieuwenhuizen, E. E., Virtue, C. J., Visser, G., Walkup, K., Ward, E. M., Wongjirad, T., Yang, Y., Yoo, J., Yu, C. -H., and Zaalishvili, A.

Subjects
High Energy Physics - Experiment
Abstract

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., Comment: 7 pages, 5 figures

Published
2024

6. Search for charge non-conservation and Pauli exclusion principle violation with the Majorana Demonstrator

Author

Arnquist, IJ, Avignone, FT, Barabash, AS, Barton, CJ, Bhimani, KH, Blalock, E, Bos, B, Busch, M, Buuck, M, Caldwell, TS, Chan, Y-D, Christofferson, CD, Chu, P-H, Clark, ML, Cuesta, C, Detwiler, JA, Efremenko, Yu, Ejiri, H, Elliott, SR, Giovanetti, GK, Green, MP, Gruszko, J, Guinn, IS, Guiseppe, VE, Haufe, CR, Henning, R, Aguilar, D Hervas, Hoppe, EW, Hostiuc, A, Kidd, MF, Kim, I, Lannen V, RT, Lannen, IE, Li, A, Lopez-Castano, JM, Martin, EL, Martin, RD, Massarczyk, R, Meijer, SJ, Oli, TK, Paudel, LS, Pettus, W, Poon, AWP, Radford, DC, Reine, AL, Rielage, K, Ruof, NW, Schaper, DC, Tedeschi, D, Varner, RL, Vasilyev, S, Wilkerson, JF, Wiseman, C, Xu, W, Yu, C-H, and Zhu, BX

Subjects
Nuclear and Plasma Physics, Particle and High Energy Physics, Physical Sciences, Mathematical Sciences, Fluids & Plasmas, Mathematical sciences, Physical sciences
Abstract

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→νeνe¯νe 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.

Published
2024

7. Accessing new physics with an undoped, cryogenic CsI CEvNS detector for COHERENT at the SNS

Author

Barbeau, P. S., Belov, V., Bernardi, I., Bock, C., Bolozdynya, A., Bouabid, R., Browning, J., Cabrera-Palmer, B., Conley, E., da Silva, V., Daughhetee, J., Detwiler, J., Ding, K., Durand, M. R., Efremenko, Y., Elliott, S. R., Erlandson, A., Fabris, L., Febbraro, M., Galindo-Uribarri, A., Green, M. P., Hakenmüller, J., Heath, M. R., Hedges, S., Johnson, B. A., Johnson, T., Khromov, A., Konovalov, A., Kozlova, E., Kumpan, A., Kyzylova, O., Link, J. M., Liu, J., Major, A., Mann, K., Markoff, D. M., Mattingly, J., Mueller, P. E., Newby, J., Ogoi, N., O'Reilly, J., Parno, D. S., Pérez-Loureiro, D., Penttila, S. I., Pershey, D., Prior, C. G., Queen, J., Rapp, R., Ray, H., Razuvaeva, O., Reyna, D., Rich, G. C., Rudik, D., Runge, J., Salvat, D. J., Sander, J., Scholberg, K., Shakirov, A., Simakov, G., Snow, W. M., Sosnovtsev, V., Stringer, M., Subedi, T., Suh, B., Sur, B., Tayloe, R., Tellez-Giron-Flores, K., Tsai, Y. -T., Vanderwerp, J., van Nieuwenhuizen, E. E., Varner, R. L., Virtue, C. J., Visser, G., Walkup, K., Ward, E. M., Wongjirad, T., Yang, Y., Yoo, J., Yu, C. -H., and Zaalishvili, A.

Subjects
High Energy Physics - Experiment, Physics - Instrumentation and Detectors
Abstract

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.

Published
2023

8. Exotic Dark Matter Search with the Majorana Demonstrator

Author

Arnquist, IJ, Avignone, FT, Barabash, AS, Barton, CJ, Bhimani, KH, Blalock, E, Bos, B, Busch, M, Buuck, M, Caldwell, TS, Chan, Y-D, Christofferson, CD, Chu, P-H, Clark, ML, Cuesta, C, Detwiler, JA, Efremenko, Yu, Ejiri, H, Elliott, SR, Giovanetti, GK, Green, MP, Gruszko, J, Guinn, IS, Guiseppe, VE, Haufe, CR, Henning, R, Hervas Aguilar, D, Hoppe, EW, Hostiuc, A, Kidd, MF, Kim, I, Kouzes, RT, Lannen V, TE, Li, A, Lopez, AM, López-Castaño, JM, Martin, EL, Martin, RD, Massarczyk, R, Meijer, SJ, Mertens, S, Oli, TK, Othman, G, Paudel, LS, Pettus, W, Poon, AWP, Radford, DC, Rager, J, Reine, AL, Rielage, K, Ruof, NW, Schaper, DC, Tedeschi, D, Varner, RL, Vasilyev, S, Wilkerson, JF, Wiseman, C, Xu, W, Yu, C-H, and Zhu, BX

Subjects
Nuclear and Plasma Physics, Particle and High Energy Physics, Physical Sciences, Majorana Collaboration, Mathematical Sciences, Engineering, General Physics, Mathematical sciences, Physical sciences
Abstract

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.

Published
2024

9. Majorana Demonstrator Data Release for AI/ML Applications

Author

Arnquist, I. J., Avignone III, F. T., Barabash, A. S., Barton, C. J., Bhimani, K. H., Blalock, E., Bos, B., Busch, M., Buuck, M., Caldwell, T. S., Chan, Y. -D., Christofferson, C. D., Chu, P. -H., Clark, M. L., Cuesta, C., Detwiler, J. A., Efremenko, Yu., Ejiri, H., Elliott, S. R., Fuad, N., Giovanetti, G. K., Green, M. P., Gruszko, J., Guinn, I. S., Guiseppe, V. E., Haufe, C. R., Henning, R., Aguilar, D. Hervas, Hoppe, E. W., Hostiuc, A., Kidd, M. F., Kim, I., Kouzes, R. T., Lannen V, T. E., Li, A., Lopez-Castano, J. M., Martin, R. D., Massarczyk, R., Meijer, S. J., Mertens, S., Oli, T. K., Paudel, L. S., Pettus, W., Poon, A. W. P., Quenallata, B., Radford, D. C., Reine, A. L., Rielage, K., Ruof, N. W., Schaper, D. C., Schleich, S. J., Tedeschi, D., Varner, R. L., Vasilyev, S., Watkins, S. L., Wilkerson, J. F., Wiseman, C., Xu, W., Yu, C. -H., and Zhu, B. X.

Subjects
Computer Science - Machine Learning, Nuclear Experiment, Physics - Data Analysis, Statistics and Probability, Physics - Instrumentation and Detectors
Abstract

The enclosed data release consists of a subset of the calibration data from the Majorana Demonstrator experiment. Each Majorana event is accompanied by raw Germanium detector waveforms, pulse shape discrimination cuts, and calibrated final energies, all shared in an HDF5 file format along with relevant metadata. This release is specifically designed to support the training and testing of Artificial Intelligence (AI) and Machine Learning (ML) algorithms upon our data. This document is structured as follows. Section I provides an overview of the dataset's content and format; Section II outlines the location of this dataset and the method for accessing it; Section III presents the NPML Machine Learning Challenge associated with this dataset; Section IV contains a disclaimer from the Majorana collaboration regarding the use of this dataset; Appendix A contains technical details of this data release. Please direct questions about the material provided within this release to liaobo77@ucsd.edu (A. Li)., Comment: DataPlanet Access: https://dataplanet.ucsd.edu/dataset.xhtml?persistentId=perma:83.ucsddata/UQWQAV

Published
2023

10. COHERENT Collaboration data release from the measurements of CsI[Na] response to nuclear recoils

Author

Akimov, D., An, P., Awe, C., Barbeau, P. S., Becker, B., Belov, V., Bernardi, I., Blackston, M. A., Bock, C., Bolozdynya, A., Browning, J., Cabrera-Palmer, B., Chernyak, D., Conley, E., Daughhetee, J., Detwiler, J., Ding, K., Durand, M. R., Efremenko, Y., Elliott, S. R., Fabris, L., Febbraro, M., Rosso, A. Gallo, Galindo-Uribarri, A., Green, M. P., Heath, M. R., Hedges, S., Hoang, D., Hughes, M., Johnson, T., Khromov, A., Konovalov, A., Kozlova, E., Kumpan, A., Li, L., Link, J. M., Liu, J., Mann, K., Markoff, D. M., Mastroberti, J., Mueller, P. E., Newby, J., Parno, D. S., Penttila, S. I., Pershey, D., Rapp, R., Ray, H., Raybern, J., Razuvaeva, O., Reyna, D., Rich, G. C., Ross, J., Rudik, D., Runge, J., Salvat, D. J., Salyapongse, A. M., Sander, J., Scholberg, K., Shakirov, A., Simakov, G., Sinev, G., Snow, W. M., Sosnovtsev, V., Suh, B., Tayloe, R., Tellez-Giron-Flores, K., Tolstukhin, I., Ujah, E., Vanderwerp, J., Varner, R. L., Virtue, C. J., Visser, G., Wongjirad, T., Yang, Y., Yen, Y. -R., Yoo, J., Yu, C. -H., and Zettlemoyer, J.

Subjects
Physics - Instrumentation and Detectors
Abstract

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.

Published
2023

11. Constraints on the Decay of Ta180m

Author

Arnquist, IJ, Avignone, FT, Barabash, AS, Barton, CJ, Bhimani, KH, Blalock, E, Bos, B, Busch, M, Buuck, M, Caldwell, TS, Christofferson, CD, Chu, P-H, Clark, ML, Cuesta, C, Detwiler, JA, Efremenko, Yu, Ejiri, H, Elliott, SR, Giovanetti, GK, Goett, J, Green, MP, Gruszko, J, Guinn, IS, Guiseppe, VE, Haufe, CR, Henning, R, Aguilar, D Hervas, Hoppe, EW, Hostiuc, A, Kim, I, Kouzes, RT, V., TE Lannen, Li, A, López-Castaño, JM, Massarczyk, R, Meijer, SJ, Meijer, W, Oli, TK, Paudel, LS, Pettus, W, Poon, AWP, Radford, DC, Reine, AL, Rielage, K, Rouyer, A, Ruof, NW, Schaper, DC, Schleich, SJ, Smith-Gandy, TA, Tedeschi, D, Thompson, JD, Varner, RL, Vasilyev, S, Watkins, SL, Wilkerson, JF, Wiseman, C, Xu, W, Yu, C-H, Alves, DSM, Hebenstiel, L, and Ramani, H

Subjects
Nuclear and Plasma Physics, Particle and High Energy Physics, Synchrotrons and Accelerators, Physical Sciences, Affordable and Clean Energy, Majorana Collaboration, Mathematical Sciences, Engineering, General Physics, Mathematical sciences, Physical sciences
Abstract

^{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}

Published
2023

12. Energy Calibration of Germanium Detectors for the MAJORANA DEMONSTRATOR

Author

Arnquist, I. J., Avignone III, F. T., Barabash, A. S., Barton, C. J., Bhimani, K. H., Blalock, E., Bos, B., Busch, M., Buuck, M., Caldwell, T. S., Chan, Y-D., Christofferson, C. D., Chu, P. -H., Clark, M. L., Cuesta, C., Detwiler, J. A., Efremenko, Yu., Ejiri, H., Elliott, S. R., Giovanetti, G. K., Green, M. P., Gruszko, J., Guinn, I. S., Guiseppe, V. E., Haufe, C. R., Henning, R., Aguilar, D. Hervas, Hoppe, E. W., Hostiuc, A., Kidd, M. F., Kim, I., Kouzes, R. T., Lannen V, T. E., Li, A., López-Castaño, J. M., Martin, E. L., Martin, R. D., Massarczyk, R., Meijer, S. J., Oli, T. K., Paudel, L. S., Pettus, W., Poon, A. W. P., Radford, D. C., Reine, A. L., Rielage, K., Ruof, N. W., Schaper, D. C., Tedeschi, D., Varner, R. L., Vasilyev, S., Wilkerson, J. F., Wiseman, C., Xu, W., Yu, C. -H., and Zhu, B. X.

Subjects
Physics - Instrumentation and Detectors, Nuclear Experiment
Abstract

The MAJORANA DEMONSTRATOR was a search for neutrinoless double-beta decay ($0\nu\beta\beta$) in the $^{76}$Ge isotope. It was staged at the 4850-foot level of the Sanford Underground Research Facility (SURF) in Lead, SD. The experiment consisted of 58 germanium detectors housed in a low background shield and was calibrated once per week by deploying a $^{228}$Th line source for 1 to 2 hours. The energy scale calibration determination for the detector array was automated using custom analysis tools. We describe the offline procedure for calibration of the Demonstrator germanium detectors, including the simultaneous fitting of multiple spectral peaks, estimation of energy scale uncertainties, and the automation of the calibration procedure.

Published
2023
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13. Constraints on the decay of $^{180m}$Ta

Author

Arnquist, I. J., Avignone III, F. T., Barabash, A. S., Barton, C. J., Bhimani, K. H., Blalock, E., Bos, B., Busch, M., Buuck, M., Caldwell, T. S., Christofferson, C. D., Chu, P. -H., Clark, M. L., Cuesta, C., Detwiler, J. A., Efremenko, Yu., Ejiri, H., Elliott, S. R., Giovanetti, G. K., Goett, J., Green, M. P., Gruszko, J., Guinn, I. S., Guiseppe, V. E., Haufe, C. R., Henning, R., Aguilar, D. Hervas, Hoppe, E. W., Hostiuc, A., Kim, I., Kouzes, R. T., Lannen V, T. E., Li, A., Lopez-Castano, J. M., Massarczyk, R., Meijer, S. J., Meijer, W., Oli, T. K., Paudel, L. S., Pettus, W., Poon, A. W. P., Radford, D. C., Reine, A. L., Rielage, K., Rouyer, A., Ruof, N. W., Schaper, D. C., Schleich, S. J., Smith-Gandy, T. A., Tedeschi, D., Varner, R. L., Vasilyev, S., Watkins, S. L., Wilkerson, J. F., Wiseman, C., Xu, W., Yu, C. -H., Alves, D. S. M., and Ramani, H.

Subjects
Nuclear Experiment, High Energy Physics - Experiment
Abstract

$^{180m}$Ta is a rare nuclear isomer whose decay has never been observed. Its remarkably long lifetime surpasses the half-lives of all other known $\beta$ 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 kilograms, the largest amount of tantalum metal ever used for such a search was installed within the ultra-low background detector array. In this paper 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 x $10^{19}$ years, we improved existing limits by one to two orders of magnitude. This result is the most sensitive search for a single $\beta$ and electron capture decay ever achieved.

Published
2023
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14. Measurement of the Electron-Neutrino Charged-Current Cross Sections on ${}^{127}$I with the COHERENT NaI$\nu$E detector

Author

An, P., Awe, C., Barbeau, P. S., Becker, B., Belov, V., Bernardi, I., Bock, C., Bolozdynya, A., Bouabid, R., Brown, A., Browning, J., Cabrera-Palmer, B., Cervantes, M., Conley, E., Daughhetee, J., Detwiler, J., Ding, K., Durand, M. R., Efremenko, Y., Elliott, S. R., Fabris, L., Febbraro, M., Rosso, A. Gallo, Galindo-Uribarri, A., Germer, A. C., Green, M. P., Hakenmüller, J., Heath, M. R., Hedges, S., Hughes, M., Johnson, B. A., Johnson, T., Khromov, A., Konovalov, A., Kozlova, E., Kumpan, A., Kyzylova, O., Li, L., Link, J. M., Liu, J., Mahoney, M., Major, A., Mann, K., Markoff, D. M., Mastroberti, J., Mattingly, J., Mueller, P. E., Newby, J., Parno, D. S., Penttila, S. I., Pershey, D., Prior, C. G., Rapp, R., Ray, H., Raybern, J., Razuvaeva, O., Reyna, D., Rich, G. C., Ross, J., Rudik, D., Runge, J., Salvat, D. J., Sander, J., Scholberg, K., Shakirov, A., Simakov, G., Sinev, G., Skuse, C., Snow, W. M., Sosnovtsev, V., Subedi, T., Suh, B., Tayloe, R., Tellez-Giron-Flores, K., Tsai, Y. -T., Ujah, E., Vanderwerp, J., van Nieuwenhuizen, E. E., Varner, R. L., Virtue, C. J., Visser, G., Walkup, K., Ward, E. M., Wongjirad, T., Yoo, J., Yu, C. -H., Zawada, A., Zettlemoyer, J., and Zderic, A.

Subjects
Nuclear Experiment, High Energy Physics - Experiment
Abstract

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 ($\leq$ 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 $9.2^{+2.1}_{-1.8} \times 10^{-40}$ cm$^2$. This corresponds to a value that is $\sim$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 $5.2^{+3.4}_{-3.1} \times 10^{-40}$ and $2.2^{+3.5}_{-2.2} \times 10^{-40}$ cm$^2$, respectively., Comment: 10 pages, 7 figures

Published
2023
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15. Modeling backgrounds for the Majorana Demonstrator

Author

Haufe, CR, Arnquist, IJ, Avignone, FT, Barabash, AS, Barton, CJ, Bhimani, KH, Blalock, E, Bos, B, Busch, M, Buuck, M, Caldwell, TS, Chan, Y-D, Christofferson, CD, Chu, P-H, Clark, ML, Cuesta, C, Detwiler, JA, Efremenko, Yu, Ejiri, H, Elliott, SR, Giovanetti, GK, Green, MP, Gruszko, J, Guinn, IS, Guiseppe, VE, Henning, R, Aguilar, D Hervas, Hoppe, EW, Hostiuc, A, Kidd, MF, Kim, I, Kouzes, RT, V., TE Lannen, Li, A, Lopez, AM, López-Castaño, JM, Martin, EL, Martin, RD, Massarczyk, R, Meijer, SJ, Oli, TK, Othman, G, Paudel, LS, Pettus, W, Poon, AWP, Radford, DC, Reine, AL, Rielage, K, Ruof, NW, Schaper, DC, Tedeschi, D, Varner, RL, Vasilyev, S, Wilkerson, JF, Wiseman, C, Xu, W, Yu, C-H, and Zhu, BX

Subjects
Nuclear and Plasma Physics, Particle and High Energy Physics, Physical Sciences
Abstract

The MAJORANA DEMONSTRATOR is a neutrinoless double-beta decay (0νββ) experiment containing ~30 kg of p-type point-contact germanium detectors enriched to 88% in 76Ge and ~14 kg of natural germanium detectors. The detectors are housed in two electroformed copper cryostats and surrounded by a graded passive shield with an active muon veto. An extensive radioassay campaign was performed prior to installation to insure the use of ultra-clean materials. The DEMONSTRATOR achieved one of the lowest background rates in the region of the 0νββ Q-value, 15.7±1.4 cts/(FWHM t y) from the low-background configuration spanning most of the 64.5 kg-yr active exposure. Nevertheless this background rate is a factor of five higher than the projected background rate. This discrepancy arises from an excess of events from the 232Th decay chain. Background-model fits aim to explain the deviation from assay-based projections, potentially determine the source(s) of observed backgrounds, and allow a precise measurement of the two-neutrino double-beta decay half-life. The fits agree with earlier simulation studies, which indicate the origin of the 232Th excess is not from a near-detector component and have informed design decisions for the next-generation LEGEND experiment. Recent findings have narrowed the suspected locations for the excess activity, motivating a final simulation and assay campaign to complete the background model.

Published
2023

16. Energy calibration of germanium detectors for the Majorana Demonstrator

Author

Arnquist, IJ, Avignone, FT, Barabash, AS, Barton, CJ, Bhimani, KH, Blalock, E, Bos, B, Busch, M, Buuck, M, Caldwell, TS, Chan, Y-D, Christofferson, CD, Chu, P-H, Clark, ML, Cuesta, C, Detwiler, JA, Efremenko, Yu, Ejiri, H, Elliott, SR, Giovanetti, GK, Green, MP, Gruszko, J, Guinn, IS, Guiseppe, VE, Haufe, CR, Henning, R, Aguilar, D Hervas, Hoppe, EW, Hostiuc, A, Kidd, MF, Kim, I, Kouzes, RT, Lannen, TE, Li, A, López-Castaño, JM, Martin, EL, Martin, RD, Massarczyk, R, Meijer, SJ, Oli, TK, Paudel, LS, Pettus, W, Poon, AWP, Radford, DC, Reine, AL, Rielage, K, Ruof, NW, Schaper, DC, Tedeschi, D, Varner, RL, Vasilyev, S, Wilkerson, JF, Wiseman, C, Xu, W, Yu, C-H, Zhu, BX, and collaboration, The Majorana

Subjects
Nuclear and Plasma Physics, Particle and High Energy Physics, Synchrotrons and Accelerators, Physical Sciences, Analysis and statistical methods, Double-beta decay detectors, Pattern recognition, cluster finding, calibration and fitting methods, Gamma detectors, Engineering, Nuclear & Particles Physics, Physical sciences
Abstract

The Majorana Demonstrator was a search for neutrinoless double-beta decay (0νββ) in the 76Ge isotope. It was staged at the 4850-foot level of the Sanford Underground Research Facility (SURF) in Lead, SD. The experiment consisted of 58 germanium detectors housed in a low background shield and was calibrated once per week by deploying a 228Th line source for 1 to 2 hours. The energy scale calibration determination for the detector array was automated using custom analysis tools. We describe the offline procedure for calibration of the Demonstrator germanium detectors, including the simultaneous fitting of multiple spectral peaks, estimation of energy scale uncertainties, and the automation of the calibration procedure.

Published
2023

17. Measurement of ${}^{nat}$Pb($\nu_e$,X$n$) production with a stopped-pion neutrino source

Author

COHERENT Collaboration, An, P., Awe, C., Barbeau, P. S., Becker, B., Belling, S. W., Belov, V., Bernardi, I., Bock, C., Bolozdynya, A., Bouabid, R., Brown, A., Browning, J., Cabrera-Palmer, B., Cervantes, M., Conley, E., Daughhetee, J., Detwiler, J., Ding, K., Durand, M. R., Efremenko, Y., Elliott, S. R., Fabris, L., Febbraro, M., Rosso, A. Gallo, Galindo-Uribarri, A., Green, M. P., Hakenmüller, J., Heath, M. R., Hedges, S., Hughes, M., Johnson, B. A., Johnson, T., Khromov, A., Konovalov, A., Kozlova, E., Kumpan, A., Kyzylova, O., Li, L., Link, J. M., Liu, J., Major, A., Mann, K., Markoff, D. M., Mastroberti, J., Mattingly, J., Miller, K., Mueller, P. E., Newby, J., Parno, D. S., Penttila, S. I., Pershey, D., Prior, C. G., Rapp, R., Ray, H., Raybern, J., Razuvaeva, O., Reyna, D., Rich, G. C., Ross, J., Rudik, D., Runge, J., Salvat, D. J., Salyapongse, A. M., Sander, J., Scholberg, K., Shakirov, A., Simakov, G., Sinev, G., Snow, W. M., Sosnovtsev, V., Subedi, T., Suh, B., Tayloe, R., Tellez-Giron-Flores, K., Ujah, E., Vanderwerp, J., van Nieuwenhuizen, E. E., Varner, R. L., Virtue, C. J., Visser, G., Walkup, K., Ward, E. M., Wongjirad, T., Yoo, J., Yu, C. -H., and Zettlemoyer, J.

Subjects
High Energy Physics - Experiment, Nuclear Experiment
Abstract

Using neutrinos produced at the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory (ORNL), the COHERENT collaboration has studied the Pb($\nu_e$,X$n$) process with a lead neutrino-induced-neutron (NIN) detector. Data from this detector are fit jointly with previously collected COHERENT data on this process. A combined analysis of the two datasets yields a cross section that is $0.29^{+0.17}_{-0.16}$ times that predicted by the MARLEY event generator using experimentally-measured Gamow-Teller strength distributions, consistent with no NIN events at 1.8$\sigma$. This is the first inelastic neutrino-nucleus process COHERENT has studied, among several planned exploiting the high flux of low-energy neutrinos produced at the SNS., Comment: 11 pages, 9 figures, version accepted by Phys. Rev. D

Published
2022
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18. Neutrinoless Double Beta Decay

Author

Adams, C., Alfonso, K., Andreoiu, C., Angelico, E., Arnquist, I. J., Asaadi, J. A. A., Avignone, F. T., Axani, S. N., Barabash, A. S., Barbeau, P. S., Baudis, L., Bellini, F., Beretta, M., Bhatta, T., Biancacci, V., Biassoni, M., Bossio, E., Breur, P. A., Brodsky, J. P., Brofferio, C., Brown, E., Brugnera, R., Brunner, T., Burlac, N., Caden, E., Calgaro, S., Cao, G. F., Cao, L., Capelli, C., Cardani, L., Fernandez, R. Castillo, Cattadori, C. M., Chana, B., Chernyak, D., Christofferson, C. D., Chu, P. -H., Church, E., Cirigliano, V., Collister, R., Comellato, T., Dalmasson, J., D'Andrea, V., Daniels, T., Darroch, L., Decowski, M. P., Demarteau, M., Peixoto, S. De Meireles, Detwiler, J. A., DeVoe, R. G., Di Domizio, S., Di Marco, N., di Vacri, M. L., Dolinski, M. J., Efremenko, Yu., Elbeltagi, M., Elliott, S. R., Engel, J., Fabris, L., Fairbank, W. M., Farine, J., Febbraro, M., Figueroa-Feliciano, E., Fields, D. E., Formaggio, J. A., Foust, B. T., Franke, B., Fu, Y., Fujikawa, B. K., Gallacher, D., Gallina, G., Garfagnini, A., Gingras, C., Gironi, L., Giuliani, A., Gold, M., Gornea, R., Grant, C., Gratta, G., Green, M. P., Grinyer, G. F., Gruszko, J., Guan, Y., Guinn, I. S., Guiseppe, V. E., Gutierrez, T. D., Hansen, E. V., Hardy, C. A., Hauptman, J., Heffner, M., Heeger, K. M., Henning, R., Hergert, H., Aguilar, D. Hervas, Hodak, R., Holt, J. D., Hoppe, E. W., Horoi, M., Huang, H. Z., Inoue, K., Jamil, A., Jochum, J., Jones, B. J. P., Kaizer, J., Karapetrov, G., Kharusi, S. Al, Kidd, M. F., Kishimoto, Y., Klein, J. R., Kolomensky, Yu. G., Kontul, I., Kornoukhov, V. N., Krause, P., Krucken, R., Kumar, K. S., Lang, K., Leach, K. G., Lenardo, B. G., Leonhardt, A., Li, A., Li, G., Li, Z., Licciardi, C., Lindsay, R., Lippi, I., Liu, J., Macko, M., MacLellan, R., Macolino, C., Majidi, S., Mamedov, F., Masbou, J., Massarczyk, R., Mastbaum, A. T., Mayer, D., Mazumdar, A., Mei, D. M., Mei, Y., Meijer, S. J., Mereghetti, E., Mertens, S., Mistry, K., Mitsui, T., Moore, D. C., Morella, M., Nattress, J. T., Neuberger, M., Ngwadla, X. E., Nones, C., Novosad, V., Nygren, D. R., Ondze, J. C. Nzobadila, O'Donnell, T., Gann, G. D. Orebi, Orrell, J. L., Ortega, G. S., Ouellet, J. L., Overman, C., Pagani, L., Palusova, V., Para, A., Pavan, M., Perna, A., Pertoldi, L., Pettus, W., Piepke, A., Piseri, P., Pocar, A., Povinec, P., Psihas, F., Pullia, A., Radford, D. C., Ramonnye, G. J, Rasiwala, H., Redchuk, M., Riboldi, S., Richardson, G., Rielage, K., Rogers, L., Rowson, P. C., Rukhadze, E., Saakyan, R., Sada, C., Salamanna, G., Salamida, F., Saldanha, R., Salvat, D. J., Sangiorgio, S., Schaper, D. C., Schoenert, S., Schwarz, M., Schwartz, S. E., Shitov, Y., Simkovic, F., Singh, V., Slavickova, M., Sousa, A. C., Spadoni, F. L., Speller, D. H., Stekl, I., Sumathi, R. R., Surukuchi, P. T., Tayloe, R., Tornow, W., Torres, J. A., Totev, T. I., Triambak, S., Tyuka, O. A., Vasilyev, S. I., Velazquez, M., Viel, S., Vogl, C., von Strum, K., Wang, Q., Waters, D., Watkins, S. L., Watts, M., Wei, W. -Z., Welliver, B., Wen, Liangjian, Wichoski, U., Wilde, S., Wilkerson, J. F., Winslow, L., Wiseman, C., Wu, X., Xu, W., Yang, H., Yang, L., Yu, C. H., Zeman, J., Zennamo, J., and Zuzel, G.

Subjects
Nuclear Experiment, Nuclear Theory
Abstract

This White Paper, prepared for the Fundamental Symmetries, Neutrons, and Neutrinos Town Meeting related to the 2023 Nuclear Physics Long Range Plan, makes the case for double beta decay as a critical component of the future nuclear physics program. The major experimental collaborations and many theorists have endorsed this white paper., Comment: white paper submitted for the Fundamental Symmetries, Neutrons, and Neutrinos Town Meeting in support of the US Nuclear Physics Long Range Planning Process

Published
2022

19. Beam Background Simulation and Experiment at BEPCII

Author

Shi, H. C ., Wang, B., Shi, H. Y., Yu, C. H., Dong, M. Y., and Peng, H. P.

Subjects
Physics - Accelerator Physics, High Energy Physics - Experiment
Abstract

A high-level beam background is a crucial challenge to future upgrades to the BEPCII collider. We report on the first separate measurement of the main beam background components at BEPCII. The separation measurement enables the beam background extrapolation towards the beam parameters assumed for the upgraded BEPCII. The measured rates of each background component are also compared with a brand-new simulation based on SAD and Geant4. The discrepancy between experiment and simulation remains 1$\sim$2 magnitudes after calibration with beam lifetime, which should be further investigated.

Published
2022
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20. Erratum: Search for Spontaneous Radiation from Wave Function Collapse in the Majorana Demonstrator [Phys. Rev. Lett. 129, 080401 (2022)]

Author

Arnquist, IJ, Avignone, FT, Barabash, AS, Barton, CJ, Bhimani, KH, Blalock, E, Bos, B, Busch, M, Buuck, M, Caldwell, TS, Chan, Y-D, Christofferson, CD, Chu, P-H, Clark, ML, Cuesta, C, Detwiler, JA, Efremenko, Yu, Ejiri, H, Elliott, SR, Giovanetti, GK, Green, MP, Gruszko, J, Guinn, IS, Guiseppe, VE, Haufe, CR, Henning, R, Hervas Aguilar, D, Hoppe, EW, Hostiuc, A, Kim, I, Kouzes, RT, Lannen V, TE, Li, A, Lopez, AM, López-Castaño, JM, Martin, EL, Martin, RD, Massarczyk, R, Meijer, SJ, Oli, TK, Othman, G, Paudel, LS, Pettus, W, Poon, AWP, Radford, DC, Reine, AL, Rielage, K, Ruof, NW, Tedeschi, D, Varner, RL, Vasilyev, S, Wilkerson, JF, Wiseman, C, Xu, W, Yu, C-H, and Zhu, BX

Subjects
Quantum Physics, Physical Sciences, Majorana Collaboration, Mathematical Sciences, Engineering, General Physics, Mathematical sciences, Physical sciences
Abstract

This corrects the article DOI: 10.1103/PhysRevLett.129.080401.

Published
2023

21. Charge trapping correction and energy performance of the Majorana Demonstrator

Author

Arnquist, IJ, Avignone, FT, Barabash, AS, Barton, CJ, Bhimani, KH, Blalock, E, Bos, B, Busch, M, Buuck, M, Caldwell, TS, Chan, Y-D, Christofferson, CD, Chu, P-H, Clark, ML, Cuesta, C, Detwiler, JA, Efremenko, Yu, Ejiri, H, Elliott, SR, Giovanetti, GK, Green, MP, Gruszko, J, Guinn, IS, Guiseppe, VE, Haufe, CR, Henning, R, Aguilar, D Hervas, Hoppe, EW, Hostiuc, A, Kidd, MF, Kim, I, Kouzes, RT, V., TE Lannen, Li, A, López-Castaño, JM, Martin, EL, Martin, RD, Massarczyk, R, Meijer, SJ, Mertens, S, Oli, TK, Othman, G, Paudel, LS, Pettus, W, Poon, AWP, Radford, DC, Reine, AL, Rielage, K, Ruof, NW, Schaper, DC, Tedeschi, D, Varner, RL, Vasilyev, S, Wilkerson, JF, Wiseman, C, Xu, W, Yu, C-H, and Zhu, BX

Subjects
Nuclear and Plasma Physics, Synchrotrons and Accelerators, Physical Sciences, Affordable and Clean Energy, Nuclear and plasma physics
Abstract

P-type point contact (PPC) high-purity germanium detectors are an important technology in astroparticle and nuclear physics due to their superb energy resolution, low noise, and pulse shape discrimination capabilities. Analysis of data from the Majorana Demonstrator, a neutrinoless double-β decay experiment deploying PPC detectors enriched in Ge76, has led to several novel improvements in the analysis of PPC signals. In this work we discuss charge trapping in PPC detectors and its effect on energy resolution. Small dislocations or impurities in the crystal lattice result in trapping of charge carriers from an ionization event of interest, attenuating the signal, and degrading the measured energy. We present a modified digital pole-zero correction to the signal energy estimation that counters the effects of charge trapping and improves the energy resolution of the Majorana Demonstrator by approximately 30% to around 2.4 keV full width at half-maximum at 2039 keV, the Ge76 Q value. An alternative approach achieving similar resolution enhancement is also presented.

Published
2023

22. Modeling Backgrounds for the MAJORANA DEMONSTRATOR

Author

Haufe, C. R., Arnquist, I. J., Avignone III, F. T., Barabash, A. S., Barton, C. J., Bhimani, K. H., Blalock, E., Bos, B., Busch, M., Buuck, M., Caldwell, T. S., Chan, Y-D., Christofferson, C. D., Chu, P. -H., Clark, M. L., Cuesta, C., Detwiler, J. A., Efremenko, Yu., Ejiri, H., Elliott, S. R., Giovanetti, G. K., Green, M. P., Gruszko, J., Guinn, I. S., Guiseppe, V. E., Henning, R., Aguilar, D. Hervas, Hoppe, E. W., Hostiuc, A., Kidd, M. F., Kim, I., Kouzes, R. T., Lannen V, T. E., Li, A., Lopez, A. M., López-Castaño, J. M., Martin, E. L., Martin, R. D., Massarczyk, R., Meijer, S. J., Oli, T. K., Othman, G., Paudel, L. S., Pettus, W., Poon, A. W. P., Radford, D. C., Reine, A. L., Rielage, K., Ruof, N. W., Schaper, D. C., Tedeschi, D., Varner, R. L., Vasilyev, S., Wilkerson, J. F., Wiseman, C., Xu, W., Yu, C. -H., and Zhu, B. X.

Subjects
Nuclear Experiment
Abstract

The MAJORANA DEMONSTRATOR is a neutrinoless double-beta decay ($0\nu\beta\beta$) experiment containing $\sim$30 kg of p-type point contact germanium detectors enriched to 88% in 76Ge and $\sim$14 kg of natural germanium detectors. The detectors are housed in two electroformed copper cryostats and surrounded by a graded passive shield with active muon veto. An extensive radioassay campaign was performed prior to installation to insure the use of ultra-clean materials. The DEMONSTRATOR achieved one of the lowest background rates in the region of the $0\nu\beta\beta$ Q-value, 15.7 $\pm$ 1.4 cts/(FWHM t y) from the low-background configuration spanning most of the 64.5 kg-yr active exposure. Nevertheless this background rate is a factor of five higher than the projected background rate. This discrepancy arises from an excess of events from the 232Th decay chain. Background model fits aim to understand this deviation from assay-based projections, potentially determine the source(s) of observed backgrounds, and allow a precision measurement of the two-neutrino double-beta decay half-life. The fits agree with earlier simulation studies, which indicate the origin of the 232Th excess is not from a near-detector component and have informed design decisions for the next-generation LEGEND experiment. Recent findings have narrowed the suspected locations for the excess activity, motivating a final simulation and assay campaign to complete the background model., Comment: 8 pages, 6 figures, Proceedings from the Low Radioactivity Techniques Workshop 2022 in Rapid City, SD, USA

Published
2022

23. E2 Rotational Invariants of $0^+_1$ and $2^+_1$ states for $^{106}$Cd: the Emergence of Collective Rotation

Author

Gray, T. J., Allmond, J. M., Janssens, R. V. F., Korten, W., Stuchbery, A. E., Wood, J. L., Ayangeakaa, A. D., Bottoni, S., Bucher, B. M., Campbell, C. M., Carpenter, M. P., Crawford, H. L., David, H., Doherty, D., Fallon, P., Febbraro, M. T., Galindo-Uribarri, A., Gross, C. J., Komorowska, M., Kondev, F. G., Lauritsen, T., Macchiavelli, A. O., Napiorkowsi, P., Padilla-Rodal, E., Pain, S. D., Reviol, W., Sarantites, D. G., Savard, G., Seweryniak, D., Wu, C. Y., Yu, C. -H., and Zhu, S.

Subjects
Nuclear Experiment, Nuclear Theory
Abstract

The collective structure of $^{106}$Cd is elucidated by multi-step Coulomb excitation of a 3.849 MeV/$A$ beam of $^{106}$Cd on a 1.1 mg/cm$^2$ $^{208}$Pb target using GRETINA-CHICO2 at ATLAS. Fourteen $E2$ matrix elements were obtained. The nucleus $^{106}$Cd is a prime example of emergent collectivity that possesses a simple structure: it is free of complexity caused by shape coexistence and has a small, but collectively active number of valence nucleons. This work follows in a long and currently active quest to answer the fundamental question of the origin of nuclear collectivity and deformation, notably in the cadmium isotopes. The results are discussed in terms of phenomenological models, the shell model, and Kumar-Cline sums of $E2$ matrix elements. The ${\langle 0_2^+ ||E2||2_1^+ \rangle}$ matrix element is determined for the first time, providing a total, converged measure of the electric quadrupole strength, $\langle Q^2 \rangle$, of the first-excited $2_1^+$ level relative to the $0_1^+$ ground state, which does not show an increase as expected of harmonic and anharmonic vibrations. Strong evidence for triaxial shapes in weakly collective nuclei is indicated; collective vibrations are excluded. This is contrary to the only other cadmium result of this kind in $^{114}$Cd by C. Fahlander et al., Nucl. Phys. A485, 327 (1988), which is complicated by low-lying shape coexistence near midshell., Comment: 7 pages, 4 figures

Published
2022
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24. Charge Trapping and Energy Performance of the MAJORANA DEMONSTRATOR

Author

Arnquist, I. J., Avignone III, F. T., Barabash, A. S., Barton, C. J., Bhimani, K. H., Blalock, E., Bos, B., Busch, M., Buuck, M., Caldwell, T. S., Chan, Y-D., Christofferson, C. D., Chu, P. -H., Clark, M. L., Cuesta, C., Detwiler, J. A., Efremenko, Yu., Ejiri, H., Elliott, S. R., Giovanetti, G. K., Green, M. P., Gruszko, J., Guinn, I. S., Guiseppe, V. E., Haufe, C. R., Henning, R., Aguilar, D. Hervas, Hoppe, E. W., Hostiuc, A., Kidd, M. F., Kim, I., Kouzes, R. T., Lannen V, T. E., Li, A., López-Castaño, J. M., Martin, E. L., Martin, R. D., Massarczyk, R., Meijer, S. J., Mertens, S., Oli, T. K., Othman, G., Paudel, L. S., Pettus, W., Poon, A. W. P., Radford, D. C., Reine, A. L., Rielage, K., Ruof, N. W., Schaper, D. C., Tedeschi, D., Varner, R. L., Vasilyev, S., Wilkerson, J. F., Wiseman, C., Xu, W., Yu, C. -H., and Zhu, B. X.

Subjects
Physics - Instrumentation and Detectors
Abstract

P-type point contact (PPC) high-purity germanium detectors are an important technology in astroparticle and nuclear physics due to their superb energy resolution, low noise, and pulse shape discrimination capabilities. Analysis of data from the MAJORANA DEMONSTRATOR, a neutrinoless double-beta decay experiment deploying PPC detectors enriched in $^{76}$Ge, has led to several novel improvements in the analysis of PPC signals. In this work we discuss charge trapping in PPC detectors and its effect on energy resolution. Small dislocations or impurities in the crystal lattice result in trapping of charge carriers from an ionization event of interest, attenuating the signal and degrading the measured energy. We present a modified digital pole-zero correction to the signal energy estimation that counters the effects of charge trapping and improves the energy resolution of the MAJORANA DEMONSTRATOR by approximately 30% to around 2.4 keV FWHM at 2039 keV, the $^{76}$Ge $Q$-value. An alternative approach achieving similar resolution enhancement is also presented., Comment: 12 pages, 13 figures

Published
2022
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25. Interpretable Boosted Decision Tree Analysis for the Majorana Demonstrator

Author

Arnquist, I. J., Avignone III, F. T., Barabash, A. S., Barton, C. J., Bhimani, K. H., Blalock, E., Bos, B., Busch, M., Buuck, M., Caldwell, T. S., Chan, Y -D., Christofferson, C. D., Chu, P. -H., Clark, M. L., Cuesta, C., Detwiler, J. A., Efremenko, Yu., Elliott, S. R., Giovanetti, G. K., Green, M. P., Gruszko, J., Guinn, I. S., Guiseppe, V. E., Haufe, C. R., Henning, R., Aguilar, D. Hervas, Hoppe, E. W., Hostiuc, A., Kidd, M. F., Kim, I., Kouzes, R. T., Lannen V, T. E., Li, A., Lopez-Castano, J. M., Martin, E. L., Martin, R. D., Massarczyk, R., Meijer, S. J., Oli, T. K., Othman, G., Paudel, L. S., Pettus, W., Poon, A. W. P., Radford, D. C., Reine, A. L., Rielage, K., Ruof, N. W., Schaper, D. C., Tedeschi, D., Varner, R. L., Vasilyev, S., Wilkerson, J. F., Wiseman, C., Xu, W., and Yu, C. -H.

Subjects
Physics - Data Analysis, Statistics and Probability, Computer Science - Machine Learning, Nuclear Experiment
Abstract

The Majorana Demonstrator is a leading experiment searching for neutrinoless double-beta decay with high purity germanium detectors (HPGe). Machine learning provides a new way to maximize the amount of information provided by these detectors, but the data-driven nature makes it less interpretable compared to traditional analysis. An interpretability study reveals the machine's decision-making logic, allowing us to learn from the machine to feedback to the traditional analysis. In this work, we have presented the first machine learning analysis of the data from the Majorana Demonstrator; this is also the first interpretable machine learning analysis of any germanium detector experiment. Two gradient boosted decision tree models are trained to learn from the data, and a game-theory-based model interpretability study is conducted to understand the origin of the classification power. By learning from data, this analysis recognizes the correlations among reconstruction parameters to further enhance the background rejection performance. By learning from the machine, this analysis reveals the importance of new background categories to reciprocally benefit the standard Majorana analysis. This model is highly compatible with next-generation germanium detector experiments like LEGEND since it can be simultaneously trained on a large number of detectors., Comment: 13 pages, 9 figures

Published
2022
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26. Final Result of the MAJORANA DEMONSTRATOR's Search for Neutrinoless Double-$\beta$ Decay in $^{76}$Ge

Author

Arnquist, I. J., Avignone III, F. T., Barabash, A. S., Barton, C. J., Barton, P. J., Bhimani, K. H., Blalock, E., Bos, B., Busch, M., Buuck, M., Caldwell, T. S., Chan, Y-D., Christofferson, C. D., Chu, P. -H., Clark, M. L., Cuesta, C., Detwiler, J. A., Efremenko, Yu., Ejiri, H., Elliott, S. R., Giovanetti, G. K., Green, M. P., Gruszko, J., Guinn, I. S., Guiseppe, V. E., Haufe, C. R., Henning, R., Aguilar, D. Hervas, Hoppe, E. W., Hostiuc, A., Kidd, M. F., Kim, I., Kouzes, R. T., Lannen V, T. E., Li, A., Lopez, A. M., López-Castaño, J. M., Martin, E. L., Martin, R. D., Massarczyk, R., Meijer, S. J., Mertens, S., Oli, T. K., Othman, G., Paudel, L. S., Pettus, W., Poon, A. W. P., Radford, D. C., Reine, A. L., Rielage, K., Ruof, N. W., Schaper, D. C., Tedeschi, D., Varner, R. L., Vasilyev, S., Wilkerson, J. F., Wiseman, C., Xu, W., Yu, C. -H., and Zhu, B. X.

Subjects
Nuclear Experiment, High Energy Physics - Experiment, Physics - Instrumentation and Detectors
Abstract

The MAJORANA DEMONSTRATOR searched for neutrinoless double-$\beta$ decay ($0\nu\beta\beta$) of $^{76}$Ge using modular arrays of high-purity Ge detectors operated in vacuum cryostats in a low-background shield. The arrays operated with up to 40.4 kg of detectors (27.2 kg enriched to $\sim$88\% in $^{76}$Ge). From these measurements, the DEMONSTRATOR has accumulated 64.5 kg yr of enriched active exposure. With a world-leading energy resolution of 2.52 keV FWHM at the 2039 keV $Q_{\beta\beta}$ (0.12\%), we set a half-life limit of $0\nu\beta\beta$ in $^{76}$Ge at $T_{1/2}>8.3\times10^{25}$ yr (90\% C.L.). This provides a range of upper limits on $m_{\beta\beta}$ of $(113-269)$ meV (90\% C.L.), depending on the choice of nuclear matrix elements., Comment: 8 pages, 2 figures

Published
2022
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27. Final Result of the Majorana Demonstrator’s Search for Neutrinoless Double-β Decay in Ge76

Author

Arnquist, IJ, Avignone, FT, Barabash, AS, Barton, CJ, Barton, PJ, Bhimani, KH, Blalock, E, Bos, B, Busch, M, Buuck, M, Caldwell, TS, Chan, Y-D, Christofferson, CD, Chu, P-H, Clark, ML, Cuesta, C, Detwiler, JA, Efremenko, Yu, Ejiri, H, Elliott, SR, Giovanetti, GK, Green, MP, Gruszko, J, Guinn, IS, Guiseppe, VE, Haufe, CR, Henning, R, Hervas Aguilar, D, Hoppe, EW, Hostiuc, A, Kidd, MF, Kim, I, Kouzes, RT, Lannen V, TE, Li, A, Lopez, AM, López-Castaño, JM, Martin, EL, Martin, RD, Massarczyk, R, Meijer, SJ, Mertens, S, Oli, TK, Othman, G, Paudel, LS, Pettus, W, Poon, AWP, Radford, DC, Reine, AL, Rielage, K, Ruof, NW, Schaper, DC, Tedeschi, D, Varner, RL, Vasilyev, S, Wilkerson, JF, Wiseman, C, Xu, W, Yu, C-H, and Zhu, BX

Subjects
Nuclear and Plasma Physics, Particle and High Energy Physics, Synchrotrons and Accelerators, Physical Sciences, Majorana Collaboration, Mathematical Sciences, Engineering, General Physics, Mathematical sciences, Physical sciences
Abstract

The Majorana Demonstrator searched for neutrinoless double-β decay (0νββ) of ^{76}Ge using modular arrays of high-purity Ge detectors operated in vacuum cryostats in a low-background shield. The arrays operated with up to 40.4 kg of detectors (27.2 kg enriched to ∼88% in ^{76}Ge). From these measurements, the Demonstrator has accumulated 64.5 kg yr of enriched active exposure. With a world-leading energy resolution of 2.52 keV FWHM at the 2039 keV Q_{ββ} (0.12%), we set a half-life limit of 0νββ in ^{76}Ge at T_{1/2}>8.3×10^{25}  yr (90% C.L.). This provides a range of upper limits on m_{ββ} of (113-269) meV (90% C.L.), depending on the choice of nuclear matrix elements.

Published
2023

28. Interpretable boosted-decision-tree analysis for the Majorana Demonstrator

Author

Arnquist, IJ, Avignone, FT, Barabash, AS, Barton, CJ, Bhimani, KH, Blalock, E, Bos, B, Busch, M, Buuck, M, Caldwell, TS, Chan, Y-D, Christofferson, CD, Chu, P-H, Clark, ML, Cuesta, C, Detwiler, JA, Efremenko, Yu, Elliott, SR, Giovanetti, GK, Green, MP, Gruszko, J, Guinn, IS, Guiseppe, VE, Haufe, CR, Henning, R, Aguilar, D Hervas, Hoppe, EW, Hostiuc, A, Kidd, MF, Kim, I, Kouzes, RT, V., TE Lannen, Li, A, López-Castaño, JM, Martin, EL, Martin, RD, Massarczyk, R, Meijer, SJ, Oli, TK, Othman, G, Paudel, LS, Pettus, W, Poon, AWP, Radford, DC, Reine, AL, Rielage, K, Ruof, NW, Schaper, DC, Tedeschi, D, Varner, RL, Vasilyev, S, Wilkerson, JF, Wiseman, C, Xu, W, and Yu, C-H

Subjects
Nuclear and Plasma Physics, Physical Sciences, Nuclear and plasma physics
Abstract

The Majorana Demonstrator is a leading experiment searching for neutrinoless double-beta decay with high purity germanium (HPGe) detectors. Machine learning provides a new way to maximize the amount of information provided by these detectors, but the data-driven nature makes it less interpretable compared to traditional analysis. An interpretability study reveals the machine's decision-making logic, allowing us to learn from the machine to feed back to the traditional analysis. In this work, we present the first machine learning analysis of the data from the Majorana Demonstrator; this is also the first interpretable machine learning analysis of any germanium detector experiment. Two gradient boosted decision tree models are trained to learn from the data, and a game-theory-based model interpretability study is conducted to understand the origin of the classification power. By learning from data, this analysis recognizes the correlations among reconstruction parameters to further enhance the background rejection performance. By learning from the machine, this analysis reveals the importance of new background categories to reciprocally benefit the standard Majorana analysis. This model is highly compatible with next-generation germanium detector experiments like LEGEND since it can be simultaneously trained on a large number of detectors.

Published
2023

29. Exotic dark matter search with the Majorana Demonstrator

Author

Arnquist, I. J., Avignone III, F. T., Barabash, A. S., Barton, C. J., Bhimani, K. H., Blalock, E., Bos, B., Busch, M., Buuck, M., Caldwell, T. S., Chan, Y-D., Christofferson, C. D., Chu, P. -H., Clark, M. L., Cuesta, C., Detwiler, J. A., Efremenko, Yu., Ejiri, H., Elliott, S. R., Giovanetti, G. K., Green, M. P., Gruszko, J., Guinn, I. S., Guiseppe, V. E., Haufe, C. R., Henning, R., Aguilar, D. Hervas, Hoppe, E. W., Hostiuc, A., Kidd, M. F., Kim, I., Kouzes, R. T., Lannen V, T. E., Li, A., Lopez, A. M., López-Castaño, J. M., Martin, E. L., Martin, R. D., Massarczyk, R., Meijer, S. J., Mertens, S., Oli, T. K., Othman, G., Paudel, L. S., Pettus, W., Poon, A. W. P., Radford, D. C., Reine, A. L., Rielage, K., Ruof, N. W., Schaper, D. C., Tedeschi, D., Varner, R. L., Vasilyev, S., Wilkerson, J. F., Wiseman, C., Xu, W., Yu, C. -H., and Zhu, B. X.

Subjects
High Energy Physics - Experiment, High Energy Physics - Phenomenology
Abstract

With excellent energy resolution and ultra-low 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, $\nu_s \rightarrow \nu_a$. We report new limits on fermionic dark matter absorption ($\chi + A \rightarrow \nu + A$) and sub-GeV DM-nucleus 3$\rightarrow$2 scattering ($\chi + \chi + A \rightarrow \phi + 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., Comment: 7 pages, 6 figures

Published
2022
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30. Search for solar axions via axion-photon coupling with the Majorana Demonstrator

Author

Arnquist, I. J., Avignone III, F. T., Barabash, A. S., Barton, C. J., Bhimani, K. H., Blalock, E., Bos, B., Busch, M., Buuck, M., Caldwell, T. S., Chan, Y-D., Christofferson, C. D., Chu, P. -H., Clark, M. L., Cuesta, C., Detwiler, J. A., Efremenko, Yu., Ejiri, H., Elliott, S. R., Giovanetti, G. K., Green, M. P., Gruszko, J., Guinn, I. S., Guiseppe, V. E., Haufe, C. R., Henning, R., Aguilar, D. Hervas, Hoppe, E. W., Hostiuc, A., Kidd, M. F., Kim, I., Kouzes, R. T., Lannen V, T. E., Li, A., Lopez, A. M., López-Castaño, J. M., Martin, E. L., Martin, R. D., Massarczyk, R., Meijer, S. J., Oli, T. K., Othman, G., Paudel, L. S., Pettus, W., Poon, A. W. P., Radford, D. C., Reine, A. L., Rielage, K., Ruof, N. W., Schaper, D. C., Tedeschi, D., Varner, R. L., Vasilyev, S., Wilkerson, J. F., Wiseman, C., Xu, W., Yu, C. -H., and Zhu, B. X.

Subjects
Nuclear Experiment, High Energy Physics - Experiment
Abstract

Axions were originally proposed to explain the strong-CP problem in QCD. Through the axion-photon coupling, the Sun could be a major source of axions, which could be measured in solid state detection experiments with enhancements due to coherent Primakoff-Bragg scattering. The Majorana Demonstrator experiment has searched for solar axions with a set of $^{76}$Ge-enriched high purity germanium detectors using a 33 kg-yr exposure collected between Jan. 2017 and Nov. 2019. A temporal-energy analysis gives a new limit on the axion-photon coupling as $g_{a\gamma}<1.45\times 10^{-9}$ GeV$^{-1}$ (95% C.I.) for axions with mass up to 100 eV/$c^2$. This improves laboratory-based limits between about 1 eV/$c^2$ and 100 eV/$c^2$., Comment: Minor updates to match published version

Published
2022
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31. A COHERENT constraint on leptophobic dark matter using CsI data

Author

COHERENT Collaboration, Akimov, D., An, P., Awe, C., Barbeau, P. S., Becker, B., Belov, V., Bernardi, I., Blackston, M. A., Bock, C., Bolozdynya, A., Bouabid, R., Browning, J., Cabrera-Palmer, B., Chernyak, D., Conley, E., Daughhetee, J., Detwiler, J., Ding, K., Durand, M. R., Efremenko, Y., Elliot, S. R., Fabris, L., Febbraro, M., Rosso, A. Gallo, Galindo-Uribarri, A., Green, M. P., Heath, M. R., Hedges, S., Hoang, D., Hughes, M., Johnson, B. A., Johnson, T., Khromov, A., Konovalov, A., Kozlova, E., Kupman, A., Li, L., Link, J. M., Liu, J., Major, A., Mann, K., Markoff, D. M., Mastroberti, J., Mattingly, J., Mueller, P. E., Newby, J., Parno, D. S., Penttila, S. I., Pershey, D., Prior, C., Rapp, R., Ray, H., Razuvaeva, O., Reyna, D., Rich, G. C., Ross, J., Rudik, D., Runge, J., Salvat, D. J., Salyapongse, A. M., Sander, J., Scholberg, K., Shakirov, A., Simakov, G., Snow, W. M., Sosnovstsev, V., Suh, B., Tayloe, R., Tellez-Giron-Flores, K., Tolstukhin, I., Ujah, E., Vanderwerp, J., Varner, R. L., Virtue, C. J., Visser, G., Wongjirad, T., Yen, W. -R., Yoo, J., Yu, C. -H., and Zettlemoyer, J.

Subjects
High Energy Physics - Experiment
Abstract

We use data from the COHERENT CsI[Na] scintillation detector to constrain sub-GeV leptophobic dark matter models. This detector was built to observe low-energy nuclear recoils from coherent elastic neutrino-nucleus scattering. These capabilities enable searches for dark matter particles produced at the Spallation Neutron Source mediated by a vector portal particle with masses between 2 and 400 MeV/c$^2$. No evidence for dark matter is observed and a limit on the mediator coupling to quarks is placed. This constraint improves upon previous results by two orders of magnitude. This newly explored parameter space probes the region where the dark matter relic abundance is explained by leptophobic dark matter when the mediator mass is roughly twice the dark matter mass. COHERENT sets the best constraint on leptophobic dark matter at these masses.

Published
2022

32. The COHERENT Experimental Program

Author

Akimov, D., Alawabdeh, S., An, P., Arteaga, A., Awe, C., Barbeau, P. S., Barry, C., Becker, B., Belov, V., Bernardi, I., Blackston, M. A., Blokland, L., Bock, C., Bodur, B., Bolozdynya, A., Bouabid, R., Bracho, A., Browning, J., Cabrera-Palmer, B., Chen, N., Chernyak, D., Conley, E., Daughhetee, J., Daughtry, J., Day, E., Coello, M. del Valle, Detwiler, J., Ding, K., Durand, M. R., Efremenko, Y., Elliott, S. R., Fabris, L., Febbraro, M., Fox, W., Galambos, J., Rosso, A. Gallo, Galindo-Uribarri, A., Gilbert, C., Green, M. P., Hansen, K. R., Harris, B., Heath, M. R., Hedges, S., Henderson, R., Hoang, D., Hughes, C., Hughes, M., Iverson, E., Jairam, P., Johnson, B. A., Johnson, T., Kaufman, L., Khromov, A., Konovalov, A., Koros, J., Kozlova, E., Kumpan, A., Li, L., Librande, J. T., Link, J. M., Liu, J., Major, A., Mann, K., Markoff, D. M., Mastroberti, J., Mattingly, J., McGoldrick, O., McIntyre, M., Melikyan, Y. A., Mishra, M., Mueller, P. E., Newby, J., Parno, D. S., Penne, A., Penttila, S. I., Pershey, D., Prior, C., Radford, D., Rahman, F., Rapp, R., Ray, H., Raybern, J., Razuvaeva, O., Reyna, D., Rich, G. C., Rimal, D., Ross, J., Rouzky, A., Rudik, D., Runge, J., Salvat, D. J., Salyapongse, A. M., Sander, J., Scholberg, K., Siehien, P., Shakirov, A., Simakov, G., Sinev, G., Snow, W. M., Sosnovstsev, V., Steele, J., Hjelmstad, A. Strasbaugh, Subedi, T., Suh, B., Tayloe, R., Tellez-Giron-Flores, K., Thornton, R. T., Tolstukhin, I., Trotter, S., Tsai, F., Tsai, Y. -T., Ujah, E., Vanderwerp, J., van Nieuwenhuizen, E., Varner, R. L., Vasquez, S., Virtue, C. J., Visser, G., Walkup, K., Wang, J., Ward, E. M., Wiseman, C., Wongjirad, T., Wu, D., Yang, J., Yang, Y., Yen, Y. -R., Yoo, J., Yu, C. -H., Zettlemoyer, J., and Zhang, S.

Subjects
High Energy Physics - Experiment, Nuclear Experiment, Physics - Instrumentation and Detectors
Abstract

The COHERENT experiment located in Neutrino Alley at the Spallation Neutron Source (SNS), Oak Ridge National Laboratory (ORNL), has made the world's first two measurements of coherent elastic neutrino-nucleus scattering (CEvNS), on CsI and argon, using neutrinos produced at the SNS. The COHERENT collaboration continues to pursue CEvNS measurements on various targets as well as additional studies of inelastic neutrino-nucleus interactions, searches for accelerator-produced dark matter (DM) and physics beyond the Standard Model, using the uniquely high-quality and high-intensity neutrino source available at the SNS. This white paper describes primarily COHERENT's ongoing and near-future program at the SNS First Target Station (FTS). Opportunities enabled by the SNS Second Target Station (STS) for the study of neutrino physics and development of novel detector technologies are elaborated in a separate white paper., Comment: 38 papers, 24 figures; Snowmass contribution

Published
2022

33. Experimental study of 13C({\alpha},n)16O reactions in the Majorana Demonstrator calibration data

Author

MAJORANA Collaboration, Arnquist, I. J., Avignone III, F. T., Barabash, A. S., Barton, C. J., Bhimani, K. H., Blalock, E., Bos, B., Busch, M., Buuck, M., Caldwell, T. S., Chan, Y-D., Christofferson, C. D., Chu, P. -H., Clark, M. L., Cuesta, C., Detwiler, J. A., Efremenko, Yu., Ejiri, H., Elliott, S. R., Giovanetti, G. K., Green, M. P., Gruszko, J., Guinn, I. S., Guiseppe, V. E., Haufe, C. R., Henning, R., Aguilar, D. Hervas, Hoppe, E. W., Hostiuc, A., Kidd, M. F., Kim, I., Kouzes, R. T., Lannen V, T. E., Li, A., Lopez, A. M., Lopez-Castano, J. M., Martin, E. L., Martin, R. D., Massarczyk, R., Meijer, S. J., Oli, T. K., Othman, G., Paudel, L. S., Pettus, W., Poon, A. W. P., Radford, D. C., Reine, A. L., Rielage, K., Ruof, N. W., Tedeschi, D., Varner, R. L., Vasilyev, S., Wilkerson, J. F., Wiseman, C., Xu, W., Yu, C. -H., and Zhu, B. X.

Subjects
Nuclear Experiment, High Energy Physics - Experiment, Physics - Instrumentation and Detectors
Abstract

Neutron captures and delayed decays of reaction products are common sources of backgrounds in ultra-rare event searches. In this work, we studied $^{13}$C($\alpha,n)^{16}$O reactions induced by $\alpha$-particles emitted within the calibration sources of the \textsc{Majorana Demonstrator}. These sources are thorium-based calibration standards enclosed in carbon-rich materials. The reaction rate was estimated by using the 6129-keV $\gamma$-rays emitted from the excited $^{16}$O states that are populated when the incoming $\alpha$-particles exceed the reaction Q-value. Thanks to the excellent energy performance of the \textsc{Demonstrator}'s germanium detectors, these characteristic photons can be clearly observed in the calibration data. Facilitated by \textsc{Geant4} simulations, a comparison between the observed 6129-keV photon rates and predictions by a TALYS-based software was performed. The measurements and predictions were found to be consistent, albeit with large statistical uncertainties. This agreement provides support for background projections from ($\alpha,n$)-reactions in future double-beta decay search efforts., Comment: Published version

Published
2022
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34. Search for charge nonconservation and Pauli exclusion principle violation with the Majorana Demonstrator

Author

MAJORANA Collaboration, Arnquist, I. J., Avignone III, F. T., Barabash, A. S., Barton, C. J., Bhimani, K. H., Blalock, E., Bos, B., Busch, M., Buuck, M., Caldwell, T. S., Chan, Y-D., Christofferson, C. D., Chu, P. -H., Clark, M. L., Cuesta, C., Detwiler, J. A., Efremenko, Yu., Ejiri, H., Elliott, S. R., Giovanetti, G. K., Green, M. P., Gruszko, J., Guinn, I. S., Guiseppe, V. E., Haufe, C. R., Henning, R., Aguilar, D. Hervas, Hoppe, E. W., Hostiuc, A., Kidd, M. F., Kim, I., Kouzes, R. T., Lannen V, T. E., Li, A., Lopez, A. M., López-Castaño, J. M., Martin, E. L., Martin, R. D., Massarczyk, R., Meijer, S. J., Oli, T. K., Paudel, L. S., Pettus, W., Poon, A. W. P., Radford, D. C., Reine, A. L., Rielage, K., Ruof, N. W., Schaper, D. C., Tedeschi, D., Varner, R. L., Vasilyev, S., Wilkerson, J. F., Wiseman, C., Xu, W., Yu, C. -H., and Zhu, B. X.

Subjects
Nuclear Experiment, High Energy Physics - Experiment
Abstract

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 \MJD\ 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 $e \rightarrow \nu_e \overline{\nu_e} \nu_e$ 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.

Published
2022
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35. Search for Spontaneous Radiation from Wavefunction Collapse in the Majorana Demonstrator

Author

Arnquist, I. J., Avignone III, F. T., Barabash, A. S., Barton, C. J., Blalock, E., Bos, B., Busch, M., Buuck, M., Caldwell, T. S., Chan, Y-D., Christofferson, C. D., Chu, P. -H., Clark, M. L., Cuesta, C., Detwiler, J. A., Efremenko, Yu., Ejiri, H., Elliott, S. R., Giovanetti, G. K., Green, M. P., Gruszko, J., Guinn, I. S., Guiseppe, V. E., Haufe, C. R., Henning, R., Aguilar, D. Hervas, Hoppe, E. W., Hostiuc, A., Kim, I., Kouzes, R. T., Lannen V, T. E., Lopez, A. M., López-Castaño, J. M., Martin, E. L., Martin, R. D., Massarczyk, R., Meijer, S. J., Oli, T. K., Othman, G., Paudel, L. S., Pettus, W., Poon, A. W. P., Radford, D. C., Reine, A. L., Rielage, K., Ruof, N. W., Tedeschi, D., Varner, R. L., Vasilyev, S., Wilkerson, J. F., Wiseman, C., Xu, W., Yu, C. -H., and Zhu, B. X.

Subjects
Nuclear Experiment, High Energy Physics - Experiment
Abstract

The Majorana Demonstrator neutrinoless double-beta decay experiment comprises a 44 kg (30 kg enriched in $^{76}\mathrm{Ge}$) array of $p$-type, point-contact germanium detectors. With its unprecedented energy resolution and ultralow backgrounds, Majorana also searches for rare event signatures from beyond standard model physics in the low energy region below 100 keV. In this Letter, we test the continuous spontaneous localization (CSL) model, one of the mathematically well-motivated wave function collapse models aimed at solving the long-standing unresolved quantum mechanical measurement problem. While the CSL predicts the existence of a detectable radiation signature in the x-ray domain, we find no evidence of such radiation in the 19--100 keV range in a 37.5 kg-y enriched germanium exposure collected between December 31, 2015, and November 27, 2019, with the Demonstrator. We explored both the non-mass-proportional (n-m-p) and the mass-proportional (m-p) versions of the CSL with two different assumptions: that only the quasifree electrons can emit the x-ray radiation and that the nucleus can coherently emit an amplified radiation. In all cases, we set the most stringent upper limit to date for the white CSL model on the collapse rate, $\lambda$, providing a factor of 40--100 improvement in sensitivity over comparable searches. Our limit is the most stringent for large parts of the allowed parameter space. If the result is interpreted in terms of the Di\`osi-Penrose gravitational wave function collapse model, the lower bound with a 95% confidence level is almost an order of magnitude improvement over the previous best limit., Comment: This document was corrected in accordance with the erratum: https://doi.org/10.1103/PhysRevLett.130.239902. The number presented in the recent version of this article is correct

Published
2022
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36. Search for Spontaneous Radiation from Wave Function Collapse in the Majorana Demonstrator

Author

Arnquist, IJ, Avignone, FT, Barabash, AS, Barton, CJ, Bhimani, KH, Blalock, E, Bos, B, Busch, M, Buuck, M, Caldwell, TS, Chan, Y-D, Christofferson, CD, Chu, P-H, Clark, ML, Cuesta, C, Detwiler, JA, Efremenko, Yu, Ejiri, H, Elliott, SR, Giovanetti, GK, Green, MP, Gruszko, J, Guinn, IS, Guiseppe, VE, Haufe, CR, Henning, R, Hervas Aguilar, D, Hoppe, EW, Hostiuc, A, Kim, I, Kouzes, RT, Lannen V, TE, Li, A, Lopez, AM, López-Castaño, JM, Martin, EL, Martin, RD, Massarczyk, R, Meijer, SJ, Oli, TK, Othman, G, Paudel, LS, Pettus, W, Poon, AWP, Radford, DC, Reine, AL, Rielage, K, Ruof, NW, Tedeschi, D, Varner, RL, Vasilyev, S, Wilkerson, JF, Wiseman, C, Xu, W, Yu, C-H, and Zhu, BX

Subjects
Nuclear and Plasma Physics, Particle and High Energy Physics, Physical Sciences, Majorana Collaboration, Mathematical Sciences, Engineering, General Physics, Mathematical sciences, Physical sciences
Abstract

The Majorana Demonstrator neutrinoless double-beta decay experiment comprises a 44 kg (30 kg enriched in ^{76}Ge) array of p-type, point-contact germanium detectors. With its unprecedented energy resolution and ultralow backgrounds, Majorana also searches for rare event signatures from beyond standard model physics in the low energy region below 100 keV. In this Letter, we test the continuous spontaneous localization (CSL) model, one of the mathematically well-motivated wave function collapse models aimed at solving the long-standing unresolved quantum mechanical measurement problem. While the CSL predicts the existence of a detectable radiation signature in the x-ray domain, we find no evidence of such radiation in the 19-100 keV range in a 37.5 kg-y enriched germanium exposure collected between December 31, 2015, and November 27, 2019, with the Demonstrator. We explored both the non-mass-proportional (n-m-p) and the mass-proportional (m-p) versions of the CSL with two different assumptions: that only the quasifree electrons can emit the x-ray radiation and that the nucleus can coherently emit an amplified radiation. In all cases, we set the most stringent upper limit to date for the white CSL model on the collapse rate, λ, providing a factor of 40-100 improvement in sensitivity over comparable searches. Our limit is the most stringent for large parts of the allowed parameter space. If the result is interpreted in terms of the Diòsi-Penrose gravitational wave function collapse model, the lower bound with a 95% confidence level is almost an order of magnitude improvement over the previous best limit.

Published
2022

37. Search for Solar Axions via Axion-Photon Coupling with the Majorana Demonstrator

Author

Arnquist, IJ, Avignone, FT, Barabash, AS, Barton, CJ, Bhimani, KH, Blalock, E, Bos, B, Busch, M, Buuck, M, Caldwell, TS, Chan, Y-D, Christofferson, CD, Chu, P-H, Clark, ML, Cuesta, C, Detwiler, JA, Efremenko, Yu, Ejiri, H, Elliott, SR, Giovanetti, GK, Green, MP, Gruszko, J, Guinn, IS, Guiseppe, VE, Haufe, CR, Henning, R, Hervas Aguilar, D, Hoppe, EW, Hostiuc, A, Kidd, MF, Kim, I, Kouzes, RT, Lannen V, TE, Li, A, Lopez, AM, López-Castaño, JM, Martin, EL, Martin, RD, Massarczyk, R, Meijer, SJ, Oli, TK, Othman, G, Paudel, LS, Pettus, W, Poon, AWP, Radford, DC, Reine, AL, Rielage, K, Ruof, NW, Schaper, DC, Tedeschi, D, Varner, RL, Vasilyev, S, Wilkerson, JF, Wiseman, C, Xu, W, Yu, C-H, and Zhu, BX

Subjects
Particle and High Energy Physics, Physical Sciences, Majorana Collaboration, Mathematical Sciences, Engineering, General Physics, Mathematical sciences, Physical sciences
Abstract

Axions were originally proposed to explain the strong-CP problem in QCD. Through axion-photon coupling, the Sun could be a major source of axions, which could be measured in solid state detection experiments with enhancements due to coherent Primakoff-Bragg scattering. The Majorana Demonstrator experiment has searched for solar axions with a set of ^{76}Ge-enriched high purity germanium detectors using a 33 kg-yr exposure collected between January, 2017 and November, 2019. A temporal-energy analysis gives a new limit on the axion-photon coupling as g_{aγ}

Published
2022

38. Monitoring the SNS basement neutron background with the MARS detector

Author

COHERENT Collaboration, Akimov, D., An, P., Awe, C., Barbeau, P. S., Becker, B., Belov, V., Bernardi, I., Blackston, M. A., Bock, C., Bolozdynya, A., Browning, J., Cabrera-Palmer, B., Chernyak, D., Conley, E., Daughhetee, J., Detwiler, J., Ding, K., Durand, M. R., Efremenko, Y., Elliott, S. R., Fabris, L., Febbraro, M., Rosso, A. Gallo, Galindo-Uribarri, A., Green, M. P., Heath, M. R., Hedges, S., Hoang, D., Hughes, M., Johnson, B. A., Johnson, T., Khromov, A., Konovalov, A., Kozlova, E., Kumpan, A., Li, L., Link, J. M., Liu, J., Mann, K., Markoff, D. M., Mastroberti, J., Mueller, P. E., Newby, J., Parno, D. S., Penttila, S. I., Pershey, D., Rapp, R., Ray, H., Raybern, J., Razuvaeva, O., Reyna, D., Rich, G. C., Ross, J., Rudik, D., Runge, J., Salvat, D. J., Salyapongse, A. M., Scholberg, K., Shakirov, A., Simakov, G., Sinev, G., Snow, W. M., Sosnovstsev, V., Suh, B., Tayloe, R., Tellez-Giron-Flores, K., Tolstukhin, I., Ujah, E., Vanderwerp, J., Varner, R. L., Virtue, C. J., Visser, G., Wongjirad, T., Yen, Y. -R., Yoo, J., Yu, C. -H., and Zettlemoyer, J.

Subjects
Physics - Instrumentation and Detectors, High Energy Physics - Experiment
Abstract

We present the analysis and results of the first dataset collected with the MARS neutron detector deployed at the Oak Ridge National Laboratory Spallation Neutron Source (SNS) for the purpose of monitoring and characterizing the beam-related neutron (BRN) background for the COHERENT collaboration. MARS was positioned next to the COH-CsI coherent elastic neutrino-nucleus scattering detector in the SNS basement corridor. This is the basement location of closest proximity to the SNS target and thus, of highest neutrino flux, but it is also well shielded from the BRN flux by infill concrete and gravel. These data show the detector registered roughly one BRN per day. Using MARS' measured detection efficiency, the incoming BRN flux is estimated to be $1.20~\pm~0.56~\text{neutrons}/\text{m}^2/\text{MWh}$ for neutron energies above $\sim3.5$ MeV and up to a few tens of MeV. We compare our results with previous BRN measurements in the SNS basement corridor reported by other neutron detectors.

Published
2021
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39. The MAJORANA DEMONSTRATOR Readout Electronics System

Author

Abgrall, N., Amman, M., Arnquist, I. J., Avignone III, F. T., Barabash, A. S., Barton, C. J., Barton, P. J., Bertrand, F. E., Bhimani, K. H., Bos, B., Bradley, A. W., Burritt, T. H., Busch, M., Buuck, M., Caldwell, T. S., Chan, Y-D., Christofferson, C. D., Chu, P. -H., Clark, M. L., Cooper, R. J., Cuesta, C., Detwiler, J. A., Drobizhev, A., Edwins, D. W., Efremenko, Yu., Ejiri, H., Elliott, S. R., Gilliss, T., Giovanetti, G. K., Green, M. P., Gruszko, J., Guinn, I. S., Guiseppe, V. E., Haufe, C. R., Hegedus, R. J., Henning, R., Aguilar, D. Hervas, Hoppe, E. W., Hostiuc, A., Kidd, M. F., Kim, I., Kouzes, R. T., Li, A., Loach, J. C., Lopez, A. M., López-Castaño, J. M., Luke, P. N., Martin, E. L., Martin, R. D., Massarczyk, R., Meijer, S. J., Mertens, S., Myslik, J., Oli, T. K., Othman, G., Peterson, D., Pettus, W., Poon, A. W. P., Radford, D. C., Rager, J., Reine, A. L., Rielage, K., Robertson, R. G. H., Ruof, N. W., Sayki, B., Stortini, M. J., Tedeschi, D., Turqueti, M., Van Wechel, T. D., Varner, R. L., Vasilyev, S., Vetter, K., Wilkerson, J. F., Wiseman, C., Xu, W., Yaver, H., Yu, C. -H., Zhu, B. X., and Zimmermann, S.

Subjects
Physics - Instrumentation and Detectors, High Energy Physics - Experiment, Nuclear Experiment
Abstract

The MAJORANA DEMONSTRATOR comprises two arrays of high-purity germanium detectors constructed to search for neutrinoless double-beta decay in 76-Ge and other physics beyond the Standard Model. Its readout electronics were designed to have low electronic noise, and radioactive backgrounds were minimized by using low-mass components and low-radioactivity materials near the detectors. This paper provides a description of all components of the MAJORANA DEMONSTRATOR readout electronics, spanning the front-end electronics and internal cabling, back-end electronics, digitizer, and power supplies, along with the grounding scheme. The spectroscopic performance achieved with these readout electronics is also demonstrated., Comment: For submission to JINST, 17 figures. v2: revised version

Published
2021
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40. Measurement of scintillation response of CsI[Na] to low-energy nuclear recoils by COHERENT

Author

Akimov, D., An, P., Awe, C., Barbeau, P. S., Becker, B., Belov, V., Bernardi, I., Blackston, M. A., Bock, C., Bolozdynya, A., Browning, J., Cabrera-Palmer, B., Chernyak, D., Conley, E., Daughhetee, J., Detwiler, J., Ding, K., Durand, M. R., Efremenko, Y., Elliott, S. R., Fabris, L., Febbraro, M., Rosso, A. Gallo, Galindo-Uribarri, A., Green, M. P., Heath, M. R., Hedges, S., Hoang, D., Hughes, M., Johnson, T., Khromov, A., Konovalov, A., Kozlova, E., Kumpan, A., Li, L., Link, J. M., Liu, J., Mann, K., Markoff, D. M., Mastroberti, J., Melikyan, Y. A., Mueller, P. E., Newby, J., Parno, D. S., Penttila, S. I., Pershey, D., Rapp, R., Ray, H., Raybern, J., Razuvaeva, O., Reyna, D., Rich, G. C., Ross, J., Rudik, D., Runge, J., Salvat, D. J., Salyapongse, A. M., Scholberg, K., Shakirov, A., Simakov, G., Sinev, G., Snow, W. M., Sosnovstsev, V., Suh, B., Tayloe, R., Tellez-Giron-Flores, K., Tolstukhin, I., Ujah, E., Vanderwerp, J., Varner, R. L., Virtue, C. J., Visser, G., Wongjirad, T., Yen, Y. -R., Yoo, J., Yu, C. -H., and Zettlemoyer, J.

Subjects
Physics - Instrumentation and Detectors
Abstract

We present results of several measurements of CsI[Na] scintillation response to 3-60 keV energy nuclear recoils performed by the COHERENT collaboration using tagged neutron elastic scattering experiments and an endpoint technique. Earlier results, used to estimate the coherent elastic neutrino-nucleus scattering (CEvNS) event rate for the first observation of this process achieved by COHERENT at the Spallation Neutron Source (SNS), have been reassessed. We discuss corrections for the identified systematic effects and update the respective uncertainty values. The impact of updated results on future precision tests of CEvNS is estimated. We scrutinize potential systematic effects that could affect each measurement. In particular we confirm the response of the H11934-200 Hamamatsu photomultiplier tube (PMT) used for the measurements presented in this study to be linear in the relevant signal scale region., Comment: The version accepted by JINST. The changes made as a result of the peer review process: 1. Section 8 "Global CsI[Na] QF data fit" is expanded. The main fit result and its uncertainty is NOT CHANGED. An alternative fit is now shown in Figure 14, Figure 15 is added to further validate the assumptions in the main fit. 2. The Appendix B is restructured for clarity

Published
2021

41. Signatures of muonic activation in the Majorana Demonstrator

Author

Arnquist, I. J., Avignone III, F. T., Barabash, A. S., Barton, C. J., Bertrand, F. E., Blalock, E., Bos, B., Busch, M., Buuck, M., Caldwell, T. S., Chan, Y-D., Christofferson, C. D., Chu, P. -H., Clark, M. L., Cuesta, C., Detwiler, J. A., Edwards, T. R., Efremenko, Yu., Ejiri, H., Elliott, S. R., Giovanetti, G. K., Green, M. P., Gruszko, J., Guinn, I. S., Guiseppe, V. E., Haufe, C. R., Henning, R., Aguilar, D. Hervas, Hoppe, E. W., Hostiuc, A., Kidd, M. F., Kim, I., Kouzes, R. T., Lannen V, T. E., Lopez, A. M., López-Castaño, J. M., Martin, E. L., Martin, R. D., Massarczyk, R., Meijer, S. J., Mertens, S., Oli, T. K., Othman, G., Paudel, L. S., Pettus, W., Poon, A. W. P., Radford, D. C., Reine, A. L., Rielage, K., Ruof, N. W., Tedeschi, D., Varner, R. L., Vasilyev, S., Wilkerson, J. F., Wiseman, C., Xu, W., Yu, C. -H., and Zhu, B. X.

Subjects
Nuclear Experiment, Physics - Instrumentation and Detectors
Abstract

Experiments searching for very rare processes such as neutrinoless double-beta decay require a detailed understanding of all sources of background. Signals from radioactive impurities present in construction and detector materials can be suppressed using a number of well-understood techniques. Background from in-situ cosmogenic interactions can be reduced by siting an experiment deep underground. However, the next generation of such experiments have unprecedented sensitivity goals of 10$^{28}$ years half-life with background rates of 10$^{-5}$cts/(keV kg yr) in the region of interest. To achieve these goals, the remaining cosmogenic background must be well understood. In the work presented here, Majorana Demonstrator data is used to search for decay signatures of meta-stable germanium isotopes. Contributions to the region of interest in energy and time are estimated using simulations, and compared to Demonstrator data. Correlated time-delayed signals are used to identify decay signatures of isotopes produced in the germanium detectors. A good agreement between expected and measured rate is found and different simulation frameworks are used to estimate the uncertainties of the predictions. The simulation campaign is then extended to characterize the background for the LEGEND experiment, a proposed tonne-scale effort searching for neutrinoless double-beta decay in $^{76}$Ge., Comment: 14 pages, 12 figures

Published
2021
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42. First Probe of Sub-GeV Dark Matter Beyond the Cosmological Expectation with the COHERENT CsI Detector at the SNS

Author

Akimov, D., An, P., Awe, C., Barbeau, P. S., Becker, B., Belov, V., Bernardi, I., Blackston, M. A., Bock, C., Bolozdynya, A., Browning, J., Cabrera-Palmer, B., Chernyak, D., Conley, E., Daughhetee, J., Detwiler, J., Ding, K., Durand, M. R., Efremenko, Y., Elliott, S. R., Fabris, L., Febbraro, M., Rosso, A. Gallo, Galindo-Uribarri, A., Green, M. P., Heath, M. R., Hedges, S., Hoang, D., Hughes, M., Johnson, T., Khromov, A., Konovalov, A., Kozlova, E., Kumpan, A., Li, L., Link, J. M., Liu, J., Mann, K., Markoff, D. M., Mastroberti, J., Mueller, P. E., Newby, J., Parno, D. S., Penttila, S. I., Pershey, D., Rapp, R., Raybern, J., Razuvaeva, O., Reyna, D., Rich, G. C., Ross, J., Rudik, D., Runge, J., Salvat, D. J., Salyapongse, A. M., Sander, J., Scholberg, K., Shakirov, A., Simakov, G., Sinev, G., Snow, W. M., Sosnovstsev, V., Suh, B., Tayloe, R., Tellez-Giron-Flores, K., Tolstukhin, I., Ujah, E., Vanderwerp, J., Varner, R. L., Virtue, C. J., Visser, G., Wongjirad, T., Yen, Y. -R., Yoo, J., Yu, C. -H., and Zettlemoyer, J.

Subjects
High Energy Physics - Experiment
Abstract

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$_\text{nr}$. 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 $\alpha_D<0.64$, 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.

Published
2021

43. Measurement of the Coherent Elastic Neutrino-Nucleus Scattering Cross Section on CsI by COHERENT

Author

Akimov, D., An, P., Awe, C., Barbeau, P. S., Becker, B., Belov, V., Bernardi, I., Blackston, M. A., Bock, C., Bolozdynya, A., Browning, J., Cabrera-Palmer, B., Chernyak, D., Conley, E., Daughhetee, J., Detwiler, J., Ding, K., Durand, M. R., Efremenko, Y., Elliott, S. R., Fabris, L., Febbraro, M., Rosso, A. Gallo, Galindo-Uribarri, A., Green, M. P., Heath, M. R., Hedges, S., Hoang, D., Hughes, M., Johnson, T., Khromov, A., Konovalov, A., Kozlova, E., Kumpan, A., Li, L., Link, J. M., Liu, J., Mann, K., Markoff, D. M., Mastroberti, J., Mueller, P. E., Newby, J., Parno, D. S., Penttila, S. I., Pershey, D., Rapp, R., Ray, H., Raybern, J., Razuvaeva, O., Reyna, D., Rich, G. C., Ross, J., Rudik, D., Runge, J., Salvat, D. J., Salyapongse, A. M., Scholberg, K., Shakirov, A., Simakov, G., Sinev, G., Snow, W. M., Sosnovstsev, V., Suh, B., Tayloe, R., Tellez-Giron-Flores, K., Tolstukhin, I., Ujah, E., Vanderwerp, J., Varner, R. L., Virtue, C. J., Visser, G., Wongjirad, T., Yen, Y. -R., Yoo, J., Yu, C. -H., and Zettlemoyer, J.

Subjects
High Energy Physics - Experiment
Abstract

We measured the cross section of coherent elastic neutrino-nucleus scattering (\cevns{}) using a CsI[Na] scintillating crystal in a high flux of neutrinos produced at the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory. New data collected before detector decommissioning has more than doubled the dataset since the first observation of \cevns{}, achieved with this detector. Systematic uncertainties have also been reduced with an updated quenching model, allowing for improved precision. With these analysis improvements, the COHERENT collaboration determined the cross section to be $(165^{+30}_{-25})\times10^{-40}$~cm$^2$, consistent with the standard model, giving the most precise measurement of \cevns{} yet. The timing structure of the neutrino beam has been exploited to compare the \cevns{} cross section from scattering of different neutrino flavors. This result places leading constraints on neutrino non-standard interactions while testing lepton flavor universality and measures the weak mixing angle as $\sin^2\theta_{W}=0.220^{+0.028}_{-0.026}$ at $Q^2\approx(50\text{ MeV})^2$

Published
2021
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44. Experimental study of C13(α,n)O16 reactions in the Majorana Demonstrator calibration data

Author

Arnquist, IJ, Avignone, FT, Barabash, AS, Barton, CJ, Bhimani, KH, Blalock, E, Bos, B, Busch, M, Buuck, M, Caldwell, TS, Chan, Y-D, Christofferson, CD, Chu, P-H, Clark, ML, Cuesta, C, Detwiler, JA, Efremenko, Yu, Ejiri, H, Elliott, SR, Giovanetti, GK, Green, MP, Gruszko, J, Guinn, IS, Guiseppe, VE, Haufe, CR, Henning, R, Aguilar, D Hervas, Hoppe, EW, Hostiuc, A, Kidd, MF, Kim, I, Kouzes, RT, Lannen, TE, Li, A, Lopez, AM, López-Castaño, JM, Martin, EL, Martin, RD, Massarczyk, R, Meijer, SJ, Oli, TK, Othman, G, Paudel, LS, Pettus, W, Poon, AWP, Radford, DC, Reine, AL, Rielage, K, Ruof, NW, Tedeschi, D, Varner, RL, Vasilyev, S, Wilkerson, JF, Wiseman, C, Xu, W, Yu, C-H, and Zhu, BX

Subjects
Nuclear and Plasma Physics, Synchrotrons and Accelerators, Physical Sciences, Nuclear and plasma physics
Abstract

Neutron captures and delayed decays of reaction products are common sources of backgrounds in ultrarare event searches. In this work, we studied C13(α,n)O16 reactions induced by α particles emitted within the calibration sources of the Majorana Demonstrator. These sources are thorium-based calibration standards enclosed in carbon-rich materials. The reaction rate was estimated by using the 6129-keV γ rays emitted from the excited O16 states that are populated when the incoming α particles exceed the reaction Q value. Thanks to the excellent energy performance of the Demonstrator's germanium detectors, these characteristic photons can be clearly observed in the calibration data. Facilitated by Geant4 simulations, a comparison between the observed 6129-keV photon rates and predictions by a talys-based software was performed. The measurements and predictions were found to be consistent, albeit with large statistical uncertainties. This agreement provides support for background projections from (α,n) reactions in future double-beta decay search efforts.

Published
2022

45. The Majorana Demonstrator readout electronics system

Author

Abgrall, N, Amman, M, Arnquist, IJ, Avignone, FT, Barabash, AS, Barton, CJ, Barton, PJ, Bertrand, FE, Bhimani, KH, Bos, B, Bradley, AW, Burritt, TH, Busch, M, Buuck, M, Caldwell, TS, Chan, Y-D, Christofferson, CD, Chu, P-H, Clark, ML, Cooper, RJ, Cuesta, C, Detwiler, JA, Drobizhev, A, Edwins, DW, Efremenko, Yu, Ejiri, H, Elliott, SR, Gilliss, T, Giovanetti, GK, Green, MP, Gruszko, J, Guinn, IS, Guiseppe, VE, Haufe, CR, Hegedus, RJ, Henning, R, Aguilar, D Hervas, Hoppe, EW, Hostiuc, A, Kidd, MF, Kim, I, Kouzes, RT, Li, A, Loach, JC, Lopez, AM, López-Castaño, JM, Luke, PN, Martin, EL, Martin, RD, Massarczyk, R, Meijer, SJ, Mertens, S, Myslik, J, Oli, TK, Othman, G, Peterson, D, Pettus, W, Poon, AWP, Radford, DC, Rager, J, Reine, AL, Rielage, K, Robertson, RGH, Ruof, NW, Sayki, B, Stortini, MJ, Tedeschi, D, Turqueti, M, Van Wechel, TD, Varner, RL, Vasilyev, S, Vetter, K, Wilkerson, JF, Wiseman, C, Xu, W, Yaver, H, Yu, C-H, Zhu, BX, and Zimmermann, S

Subjects
Nuclear and Plasma Physics, Synchrotrons and Accelerators, Physical Sciences, Double-beta decay detectors, Electronic detector readout concepts, Front-end electronics for detector readout, Engineering, Nuclear & Particles Physics, Physical sciences
Abstract

The Majorana Demonstrator comprises two arrays of high-purity germanium detectors constructed to search for neutrinoless double-beta decay in 76Ge and other physics beyond the Standard Model. Its readout electronics were designed to have low electronic noise, and radioactive backgrounds were minimized by using low-mass components and low-radioactivity materials near the detectors. This paper provides a description of all components of the Majorana Demonstrator readout electronics, spanning the front-end electronics and internal cabling, back-end electronics, digitizer, and power supplies, along with the grounding scheme. The spectroscopic performance achieved with these readout electronics is also demonstrated.

Published
2022

46. Simulating the neutrino flux from the Spallation Neutron Source for the COHERENT experiment

Author

COHERENT Collaboration, Akimov, D., An, P., Awe, C., Barbeau, P. S., Becker, B., Belov, V., Bernardi, I., Blackston, M. A., Bock, C., Bolozdynya, A., Browning, J., Cabrera-Palmer, B., Chernyak, D., Conley, E., Daughhetee, J., Detwiler, J., Ding, K., Durand, M. R., Efremenko, Y., Elliott, S. R., Fabris, L., Febbraro, M., Galambos, J., Rosso, A. Gallo, Galindo-Uribarri, A., Green, M. P., Heath, M. R., Hedges, S., Hoang, D., Hughes, M., Iverson, E., Johnson, T., Khromov, A., Konovalov, A., Kozlova, E., Kumpan, A., Li, L., Link, J. M., Liu, J., Mann, K., Markoff, D. M., Mastroberti, J., McIntyre, M., Mueller, P. E., Newby, J., Parno, D. S., Penttila, S. I., Pershey, D., Rapp, R., Ray, H., Raybern, J., Razuvaeva, O., Reyna, D., Rich, G. C., Rimal, D., Ross, J., Rudik, D., Runge, J., Salvat, D. J., Salyapongse, A. M., Scholberg, K., Shakirov, A., Simakov, G., Sinev, G., Snow, W. M., Sosnovstsev, V., Suh, B., Tayloe, R., Tellez-Giron-Flores, K., Tolstukhin, I., Trotter, S., Ujah, E., Vanderwerp, J., Varner, R. L., Virtue, C. J., Visser, G., Wongjirad, T., Yen, Y. -R., Yoo, J., Yu, C. -H., Zettlemoyer, J., and Zhang, S.

Subjects
High Energy Physics - Experiment, Nuclear Experiment
Abstract

The Spallation Neutron Source (SNS) at Oak Ridge National Laboratory is a pulsed source of neutrons and, as a byproduct of this operation, an intense source of pulsed neutrinos via stopped-pion decay. The COHERENT collaboration uses this source to investigate coherent elastic neutrino-nucleus scattering and other physics with a suite of detectors. This work includes a description of our Geant4 simulation of neutrino production at the SNS and the flux calculation which informs the COHERENT studies. We estimate the uncertainty of this calculation at about 10% based on validation against available low-energy pion production data.

Published
2021

47. LEGEND-1000 Preconceptual Design Report

Author

LEGEND Collaboration, Abgrall, N., Abt, I., Agostini, M., Alexander, A., Andreoiu, C., Araujo, G. R., Avignone III, F. T., Bae, W., Bakalyarov, A., Balata, M., Bantel, M., Barabanov, I., Barabash, A. S., Barbeau, P. S., Barton, C. J., Barton, P. J., Baudis, L., Bauer, C., Bernieri, E., Bezrukov, L., Bhimani, K. H., Biancacci, V., Blalock, E., Bolozdynya, A., Borden, S., Bos, B., Bossio, E., Boston, A., Bothe, V., Bouabid, R., Boyd, S., Brugnera, R., Burlac, N., Busch, M., Caldwell, A., Caldwell, T. S., Carney, R., Cattadori, C., Chan, Y. -D., Chernogorov, A., Christofferson, C. D., Chu, P. -H., Clark, M., Cohen, T., Combs, D., Comellato, T., Cooper, R. J., Costa, I. A., D'Andrea, V., Detwiler, J. A., Di Giacinto, A., Di Marco, N., Dobson, J., Drobizhev, A., Durand, M. R., Edzards, F., Efremenko, Yu., Elliott, S. R., Engelhardt, A., Fajt, L., Faud, N., Febbraro, M. T., Ferella, F., Fields, D. E., Fischer, F., Fomina, M., Fox, H., Franchi, J., Gala, R., Galindo-Uribarri, A., Gangapshev, A., Garfagnini, A., Geraci, A., Gilbert, C., Gold, M., Gooch, C., Gradwohl, K. P., Green, M. P., Grinyer, G. F., Grobov, A., Gruszko, J., Guinn, I., Guiseppe, V. E., Gurentsov, V., Gurov, Y., Gusev, K., Hacket, B., Hagemann, F., Hakenmüeller, J., Haranczyk, M., Hauertmann, L., Haufe, C. R., Hayward, C., Heffron, B., Henkes, F., Henning, R., Aguilar, D. Hervas, Hinton, J., Hodak, R., Hoffmann, H., Hofmann, W., Hostiuc, A., Huang, J., Hult, M., Mirza, M. Ibrahim, Jochum, J., Jones, R., Judson, D., Junker, M., Kaizer, J., Kazalov, V., Kermaïdic, Y., Khushbakht, H., Kidd, M., Kihm, T., Kilgus, K., Kim, I., Klimenko, A., Knöpfle, K. T., Kochetov, O., Konovalov, S. I., Kontul, I., Kool, K., Kormos, L. L., Kornoukhov, V. N., Korosec, M., Krause, P., Kuzminov, V. V., López-Castaño, J. M., Lang, K., Laubenstein, M., León, E., Lehnert, B., Leonhardt, A., Li, A., Lindner, M., Lippi, I., Liu, X., Liu, J., Loomba, D., Lubashevskiy, A., Lubsandorzhiev, B., Lusardi, N., Müller, Y., Macko, M., Macolino, C., Majorovits, B., Mamedov, F., Maneschg, W., Manzanillas, L., Marshall, G., Martin, R. D., Martin, E. L., Massarczyk, R., Mei, D., Meijer, S. J., Mertens, S., Misiaszek, M., Mondragon, E., Morella, M., Morgan, B., Mroz, T., Muenstermann, D., Nave, C. J., Nemchenok, I., Neuberger, M., Oli, T. K., Gann, G. Orebi, Othman, G., Palušova, V., Panth, R., Papp, L., Paudel, L. S., Pelczar, K., Perez, J. Perez, Pertoldi, L., Pettus, W., Piseri, P., Poon, A. W. P., Povinec, P., Pullia, A., Radford, D. C., Ramachers, Y. A., Ransom, C., Rauscher, L., Redchuk, M., Reine, A. L., Riboldi, S., Rielage, K., Rozov, S., Rukhadze, E., Rumyantseva, N., Runge, J., Ruof, N. W., Saakyan, R., Sailer, S., Salamanna, G., Salamida, F., Salvat, D. J., Sandukovsky, V., Schönert, S., Schültz, A., Schütt, M., Schaper, D. C., Schreiner, J., Schulz, O., Schuster, M., Schwarz, M., Schwingenheuer, B., Selivanenko, O., Shafiee, M., Shevchik, E., Shirchenko, M., Shitov, Y., Simgen, H., Simkovic, F., Skorokhvatov, M., Slavickova, M., Smolek, K., Smolnikov, A., Solomon, J. A., Song, G., Starosta, K., Stekl, I., Stommel, M., Stukov, D., Sumathi, R. R., Sweigart, D. A., Szczepaniec, K., Taffarello, L., Tagnani, D., Tayloe, R., Tedeschi, D., Turqueti, M., Varner, R. L., Vasilyev, S., Veresnikova, A., Vetter, K., Vignoli, C., Vogl, C., von Sturm, K., Waters, D., Waters, J. C., Wei, W., Wiesinger, C., Wilkerson, J. F., Willers, M., Wiseman, C., Wojcik, M., Wu, V. H. -S., Xu, W., Yakushev, E., Ye, T., Yu, C. -H., Yumatov, V., Zaretski, N., Zeman, J., Zhitnikov, I., Zinatulina, D., Zschocke, A. -K., Zsigmond, A. J., Zuber, K., and Zuzel, G.

Subjects
Physics - Instrumentation and Detectors, Nuclear Experiment
Abstract

We propose the construction of LEGEND-1000, the ton-scale Large Enriched Germanium Experiment for Neutrinoless $\beta \beta$ Decay. This international experiment is designed to answer one of the highest priority questions in fundamental physics. It consists of 1000 kg of Ge detectors enriched to more than 90% in the $^{76}$Ge isotope operated in a liquid argon active shield at a deep underground laboratory. By combining the lowest background levels with the best energy resolution in the field, LEGEND-1000 will perform a quasi-background-free search and can make an unambiguous discovery of neutrinoless double-beta decay with just a handful of counts at the decay $Q$ value. The experiment is designed to probe this decay with a 99.7%-CL discovery sensitivity in the $^{76}$Ge half-life of $1.3\times10^{28}$ years, corresponding to an effective Majorana mass upper limit in the range of 9-21 meV, to cover the inverted-ordering neutrino mass scale with 10 yr of live time.

Published
2021

48. A D$_{2}$O detector for flux normalization of a pion decay-at-rest neutrino source

Author

COHERENT Collaboration, Akimov, D., An, P., Awe, C., Barbeau, P. S., Becker, B., Belov, V., Bernardi, I., Blackston, M. A., Blokland, L., Bolozdynya, A., Cabrera-Palmer, B., Chernyak, D., Conley, E., Daughhetee, J., Day, E., Detwiler, J., Ding, K., Durand, M. R., Efremenko, Y., Elliott, S. R., Fabris, L., Febbraro, M., Rosso, A. Gallo, Galindo-Uribarri, A., Green, M. P., Heath, M. R., Hedges, S., Hoang, D., Hughes, M., Johnson, T., Khromov, A., Konovalov, A., Koros, J., Kozlova, E., Kumpan, A., Li, L., Link, J. M., Liu, J., Markoff, D. M., Mann, K., Mueller, P. E., Newby, J., Parno, D. S., Penttila, S. I., Pershey, D., Rapp, R., Ray, H., Raybern, J., Razuvaeva, O., Reyna, D., Rich, G. C., Ross, J., Rudik, D., Runge, J., Salvat, D. J., Salyapongse, A. M., Scholberg, K., Shakirov, A., Simakov, G., Sinev, G., Snow, W. M., Sosnovstsev, V., Suh, B., Tayloe, R., Tellez-Giron-Flores, K., Tolstukhin, I., Ujah, E., Vanderwerp, J., Varner, R. L., Virtue, C. J., Visser, G., Ward, E. M., Wiseman, C., Wongjirad, T., Yen, Y. -R., Yoo, J., Yu, C. -H., and Zettlemoyer, J.

Subjects
Physics - Instrumentation and Detectors, High Energy Physics - Experiment, Nuclear Experiment
Abstract

We report on the technical design and expected performance of a 592 kg heavy-water-Cherenkov detector to measure the absolute neutrino flux from the pion-decay-at-rest neutrino source at the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory (ORNL). The detector will be located roughly 20 m from the SNS target and will measure the neutrino flux with better than 5% statistical uncertainty in 2 years. This heavy-water detector will serve as the first module of a two-module detector system to ultimately measure the neutrino flux to 2-3% at both the First Target Station and the planned Second Target Station of the SNS. This detector will significantly reduce a dominant systematic uncertainty for neutrino cross-section measurements at the SNS, increasing the sensitivity of searches for new physics., Comment: As accepted to JINST

Published
2021
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49. α-event characterization and rejection in point-contact HPGe detectors

Author

Arnquist, IJ, Avignone, FT, Barabash, AS, Barton, CJ, Bertrand, FE, Blalock, E, Bos, B, Busch, M, Buuck, M, Caldwell, TS, Chan, Y-D, Christofferson, CD, Chu, P-H, Clark, ML, Cuesta, C, Detwiler, JA, Drobizhev, A, Edwards, TR, Edwins, DW, Edzards, F, Efremenko, Y, Elliott, SR, Gilliss, T, Giovanetti, GK, Green, MP, Gruszko, J, Guinn, IS, Guiseppe, VE, Haufe, CR, Hegedus, RJ, Henning, R, Aguilar, D Hervas, Hoppe, EW, Hostiuc, A, Kim, I, Kouzes, RT, Lopez, AM, López-Castaño, JM, Martin, EL, Martin, RD, Massarczyk, R, Meijer, SJ, Mertens, S, Myslik, J, Oli, TK, Othman, G, Pettus, W, Poon, AWP, Radford, DC, Rager, J, Reine, AL, Rielage, K, Ruof, NW, Saykı, B, Schönert, S, Stortini, MJ, Tedeschi, D, Varner, RL, Vasilyev, S, Wilkerson, JF, Willers, M, Wiseman, C, Xu, W, Yu, C-H, and Zhu, BX

Subjects
Nuclear and Plasma Physics, Particle and High Energy Physics, Synchrotrons and Accelerators, Physical Sciences, Clinical Research, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics, Nuclear & Particles Physics, Astronomical sciences, Atomic, molecular and optical physics, Particle and high energy physics
Abstract

P-type point contact (PPC) HPGe detectors are a leading technology for rare event searches due to their excellent energy resolution, low thresholds, and multi-site event rejection capabilities. We have characterized a PPC detector's response to α particles incident on the sensitive passivated and p + surfaces, a previously poorly-understood source of background. The detector studied is identical to those in the Majorana Demonstrator experiment, a search for neutrinoless double-beta decay ( 0νββ ) in 76 Ge. α decays on most of the passivated surface exhibit significant energy loss due to charge trapping, with waveforms exhibiting a delayed charge recovery (DCR) signature caused by the slow collection of a fraction of the trapped charge. The DCR is found to be complementary to existing methods of α identification, reliably identifying α background events on the passivated surface of the detector. We demonstrate effective rejection of all surface α events (to within statistical uncertainty) with a loss of only 0.2% of bulk events by combining the DCR discriminator with previously-used methods. The DCR discriminator has been used to reduce the background rate in the 0νββ region of interest window by an order of magnitude in the Majorana Demonstrator  and will be used in the upcoming LEGEND-200 experiment.

Published
2022

50. Signatures of muonic activation in the Majorana Demonstrator

Author

Arnquist, IJ, Avignone, FT, Barabash, AS, Barton, CJ, Bertrand, FE, Blalock, E, Bos, B, Busch, M, Buuck, M, Caldwell, TS, Chan, Y-D, Christofferson, CD, Chu, P-H, Clark, ML, Cuesta, C, Detwiler, JA, Edwards, TR, Efremenko, Yu, Ejiri, H, Elliott, SR, Giovanetti, GK, Green, MP, Gruszko, J, Guinn, IS, Guiseppe, VE, Haufe, CR, Henning, R, Aguilar, D Hervas, Hoppe, EW, Hostiuc, A, Kidd, MF, Kim, I, Kouzes, RT, Lannen, TEV, Lopez, AM, López-Castaño, JM, Martin, EL, Martin, RD, Massarczyk, R, Meijer, SJ, Mertens, S, Oli, TK, Othman, G, Paudel, LS, Pettus, W, Poon, AWP, Radford, DC, Reine, AL, Rielage, K, Ruof, NW, Tedeschi, D, Varner, RL, Vasilyev, S, Wilkerson, JF, Wiseman, C, Xu, W, Yu, C-H, and Zhu, BX

Subjects
Nuclear and Plasma Physics, Particle and High Energy Physics, Synchrotrons and Accelerators, Physical Sciences, Nuclear and plasma physics
Abstract

Experiments searching for very rare processes such as neutrinoless double-beta decay require a detailed understanding of all sources of background. Signals from radioactive impurities present in construction and detector materials can be suppressed using a number of well-understood techniques. Background from in situ cosmogenic interactions can be reduced by siting an experiment deep underground. However, the next generation of such experiments have unprecedented sensitivity goals of 1028 years half-life with background rates of 10-5cts/(keV kg yr) in the region of interest. To achieve these goals, the remaining cosmogenic background must be well understood. In the work presented here, Majorana Demonstrator data are used to search for decay signatures of metastable germanium isotopes. Contributions to the region of interest in energy and time are estimated using simulations and compared to Demonstrator data. Correlated time-delayed signals are used to identify decay signatures of isotopes produced in the germanium detectors. A good agreement between expected and measured rate is found and different simulation frameworks are used to estimate the uncertainties of the predictions. The simulation campaign is then extended to characterize the background for the LEGEND experiment, a proposed tonne-scale effort searching for neutrinoless double-beta decay in Ge76.

Published
2022

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