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1. 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

2. 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

3. 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

4. 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

5. 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

6. 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

7. 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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8. 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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9. Fundamental Symmetries, Neutrons, and Neutrinos (FSNN): Whitepaper for the 2023 NSAC Long Range Plan

Author

Acharya, B., Adams, C., Aleksandrova, A. A., Alfonso, K., An, P., Baeßler, S., Balantekin, A. B., Barbeau, P. S., Bellini, F., Bellini, V., Beminiwattha, R. S., Bernauer, J. C., Bhattacharya, T., Bishof, M., Bolotnikov, A. E., Breur, P. A., Brodeur, M., Brodsky, J. P., Broussard, L. J., Brunner, T., Burdette, D. P., Caylor, J., Chiu, M., Cirigliano, V., Clark, J. A., Clayton, S. M., Daniels, T. V., Darroch, L., Davoudi, Z., de Gouvêa, A., Dekens, W., Demarteau, M., DeMille, D., Deshpande, A., Detwiler, J. A., Dodson, G. W., Dolinski, M. J., Elliott, S. R., Engel, J., Erler, J., Filippone, B. W., Fomin, N., Formaggio, J. A., Friesen, F. Q. L., Fry, J., Fujikawa, B. K., Fuller, G., Fuyuto, K., Gallant, A. T., Gallina, G., Ruiz, A. Garcia, Ruiz, R. F. Garcia, Gardner, S., Gonzalez, F. M., Gratta, G., Gruszko, J., Gudkov, V., Guiseppe, V. E., Gutierrez, T. D., Hansen, E. V., Hardy, C. A., Haxton, W. C., Hayen, L., Hedges, S., Heeger, K. M., Heffner, M., Heise, J., Henning, R., Hergert, H., Hertzog, D. W., Aguilar, D. Hervas, Holt, J. D., Hoogerheide, S. F., Hoppe, E. W., Horoi, M., Howell, C. R., Huang, M., Hutzler, N. R., Imam, K., Ito, T. M., Jamil, A., Janssens, R. V., Jayich, A. M., Jones, B. J. P., Kammel, P., Liu, K. F., Khachatryan, V., King, P. M., Klein, J. R., Kneller, J. P., Kolomensky, Yu. G., Korsch, W., Krücken, R., Kumar, K. S., Launey, K. D., Lawrence, D., Leach, K. G., Lehnert, B., Lenardo, B. G., Li, Z., Lin, H. -W., Longfellow, B., Lopez-Caceres, S., Lunardini, C., MacLellan, R., Markoff, D. M., Maruyama, R. H., Mathews, D. G., Melconian, D., Mereghetti, E., Mohanmurthy, P., Moore, D. C., Mueller, P. E., Mumm, H. P., Nazarewicz, W., Newby, J., Nicholson, A. N., Novitski, E., Ondze, J. C. Nzobadila, O'Donnell, T., Gann, G. D. Orebi, Orrell, J. L., Ouellet, J. L., Parno, D. S., Paschke, K. D., Pastore, S., Pattie Jr, R. W., Petrov, A. A., Pitt, M. L., Plaster, B., Pocanic, D., Pocar, A., Poon, A. W. P., Radford, D. C., Rahangdale, H., Rasco, B. C., Rasiwala, H., Redwine, R. P., Ritz, A., Rogers, L., Ron, G., Saldanha, R., Sangiorgio, S., Sargsyan, G. H., Saunders, A., Savard, G., Schaper, D. C., Scholberg, K., Scielzo, N. D., Seng, C. -Y., Shindler, A., Singh, J. T., Singh, M., Singh, V., Snow, W. M., Soma, A. K., Souder, P. A., Speller, D. H., Stachurska, J., Surukuchi, P. T., Oregui, B. Tapia, Tomalak, O., Torres, J. A., Tyuka, O. A., VanDevender, B. A., Varriano, L., Vogt, R., Walker-Loud, A., Wamba, K., Watkins, S. L., Wietfeldt, F. E., Williams, W. D., Wilson, J. T., Winslow, L., Yan, X. L., Yang, L., Young, A. R., Zheng, X., and Zhou, Y.

Subjects
Nuclear Experiment, Nuclear Theory
Abstract

This whitepaper presents the research priorities decided on by attendees of the 2022 Town Meeting for Fundamental Symmetries, Neutrons and Neutrinos, which took place December 13-15, 2022 in Chapel Hill, NC, as part of the Nuclear Science Advisory Committee (NSAC) 2023 Long Range Planning process. A total of 275 scientists registered for the meeting. The whitepaper makes a number of explicit recommendations and justifies them in detail.

Published
2023

10. 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

11. 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

12. Variance Sum Rule for Entropy Production

Author

Di Terlizzi, I., Gironella, M., Herraez-Aguilar, D., Betz, T., Monroy, F., Baiesi, M., and Ritort, F.

Subjects
Physics - Biological Physics, Condensed Matter - Soft Condensed Matter, Condensed Matter - Statistical Mechanics, 82A02
Abstract

Entropy production is the hallmark of nonequilibrium physics, quantifying irreversibility, dissipation, and the efficiency of energy transduction processes. Despite many efforts, its measurement at the nanoscale remains challenging. We introduce a variance sum rule for displacement and force variances that permits us to measure the entropy production rate $\sigma$ in nonequilibrium steady states. We first illustrate it for directly measurable forces, such as an active Brownian particle in an optical trap. We then apply the variance sum rule to flickering experiments in human red blood cells. We find that $\sigma$ is spatially heterogeneous with a finite correlation length and its average value agrees with calorimetry measurements. The VSR paves the way to derive $\sigma$ using force spectroscopy and time-resolved imaging in living and active matter., Comment: 5 pages and 4 figures. It also contains Supp. Info. with 6 additional figures and 4 tables

Published
2023
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13. 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

14. 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

15. 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

17. 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

18. 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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19. 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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20. 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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21. 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

22. 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

23. 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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24. 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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25. 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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26. 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 (PEP) result from fundamental symmetries in the Standard Model, and are typically taken as axiomatic. High-precision tests for small violations of these symmetries could point to new physics. In this work we consider three models for violation of these processes which would produce detectable ionization in the high-purity germanium detectors of the Majorana Demonstrator. Using a 37.5 kg-yr exposure, we report a new lower limit on the electron mean lifetime of $\tau_e > 3.2 \times 10^{25}$ yr (90\% CL), the best result for this decay channel ($e \rightarrow \nu_e \overline{\nu_e} \nu_e$ or more generally $e \rightarrow \mathrm{invisibles}$) in more than two decades. We also present searches for two types of violation of the PEP, setting new limits on the probability of two electrons forming a symmetric quantum state. Using our $^{228}$Th calibration data set, which introduces electrons new to the system through electron-positron pair production, we obtain a world-leading model-independent limit for a terrestrial experiment of $\beta^2/2 < 1.0 \times 10^{-3}$ (99.7\% CL). Our 37.5 kg-yr exposure is also used to search for a process where an electron in an atomic system spontaneously violates the PEP, resulting in a model-dependent upper limit of $\beta^2/2 < 1.0 \times 10^{-48}$ (90\% CL).

Published
2022
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27. A novel wide-angle Compton Scanner setup to study bulk events in germanium detectors

Author

Abt, I., Gooch, C., Hagemann, F., Hauertmann, L., Aguilar, D. Hervas, Liu, X., Schulz, O., Schuster, M., and Zsigmond, A. J.

Subjects
Physics - Instrumentation and Detectors
Abstract

A novel Compton Scanner setup has been built, commissioned and operated at the Max-Planck-Institute for Physics in Munich to collect pulses from bulk events in high-purity germanium detectors for pulse shape studies. In this fully automated setup, the detector under test is irradiated from the top with 661.660 keV gammas, some of which Compton scatter inside the detector. The interaction points in the detector can be reconstructed when the scattered gammas are detected with a pixelated camera placed at the side of the detector. The wide range of accepted Compton angles results in shorter measurement times in comparison to similar setups where only perpendicularly scattered gammas are selected by slit collimators. In this paper, the construction of the Compton Scanner, its alignment and the procedure to reconstruct interaction points in the germanium detector are described in detail. The creation of a first pulse shape library for an n-type segmented point-contact germanium detector is described. The spatial reconstruction along the beam axis is validated by a comparison to measured surface pulses. A first comparison of Compton Scanner pulses to simulated pulses is presented to demonstrate the power of the Compton Scanner to test simulation inputs and models., Comment: 15 pages, 18 figures

Published
2022
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28. 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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29. 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

30. 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

31. 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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32. 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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33. 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

34. 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

35. 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

36. Fungal and bacterial communities in a forest relict of Pinus pseudostrobus var. coatepecensis

Author

Baeza-Guzmán Y, Camargo-Ricalde SL, Trejo Aguilar D, and Montaño NM

Subjects
Bacteria, Diversity, Soil, Ectomycorrhizal Fungi, Pinus, Plantation, Forestry, SD1-669.5
Abstract

Mexico is a center of diversity for the genus Pinus, with 44% of pine species being endemic to the country. Mexican pine forests are recognized as hotspots for ectomycorrhizal fungi and bacteria due to the extensive interactions that take place between microorganisms and plants in their roots. These microorganisms play a vital role in the survival of pine species. This study aims to identify fungal and bacterial communities in a relict Mexican pine forest and evaluate the influence of soil physicochemical parameters on microbial composition. Sampling was conducted along a 145 m transect in an isolated natural relict of P. pseudostrobus var. coatepecensis, which is located within a commercial plantation of Pinus patula. A total of 18 soil samples were collected at predetermined distances along the transect, with replicated sampling points as follows: six samples at 20 cm intervals, four samples at 1 m intervals, four samples at 10 m intervals, and four samples at 25 m intervals. The results indicate that fungal composition varies even at short distances and is influenced by the C:N ratio, total carbon (C), total phosphorus (P), and total hydrogen ion concentration (H+). Ectomycorrhizal fungi (EcM) exhibited a higher relative abundance compared to saprotrophic and pathogenic fungi. A total of 69 EcM ASVs (Amplicon Sequence Variants) were identified, being the dominant genera Tomentella, Clavulina, Suillus, Russula, and Elaphomyces. Bacterial communities did not show significant variation in relation to the distance from the sampling points, but soil pH was identified as the main factor of bacterial composition. Dominant bacterial genera included Burkholderia, Bryobacter, Acidobacterium, and Acidothermus. Additionally, it was observed that current soil conditions influenced β diversity. Overall, the results demonstrate that soil fungal and bacterial communities associated with P. pseudostrobus exhibit a unique composition compared to other natural forest systems in the Neotropics.

Published
2023
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37. 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

38. 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

39. 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., 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., Drobizhev, A., Edwards, T. R., 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., Henning, R., Aguilar, D. Hervas, Hoppe, E. W., Hostiuc, A., Kidd, M. F., Kim, I., Kouzes, R. T., Lopez, A. M., López-Castaño, J. M., Martin, E. L., Martin, R. D., Massarczyk, R., Meijer, S. J., Mertens, S., Myslik, 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., Saykı, B., Stortini, M. J., 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 search consisting of a low-background modular array of high-purity germanium detectors, $\sim2/3$ of which are enriched to 88\% in $^{76}$Ge. The experiment is also searching for double-beta decay of $^{76}$Ge to excited states (e.s.) in $^{76}$Se. $^{76}$Ge can decay into three daughter states of $^{76}$Se, with clear event signatures consisting of a $\beta\beta$-decay followed by the prompt emission of one or two $\gamma$-rays. This results with high probability in multi-detector coincidences. The granularity of the Demonstrator detector array enables powerful discrimination of this event signature from backgrounds. Using 41.9~kg-y of isotopic exposure, the Demonstrator has set world leading limits for each e.s.\ decay of $^{76}$Ge, with 90\% CL lower half-life limits in the range of $(0.75-4.0)\times10^{24}$~y. In particular, for the $2\nu$ transition to the first $0^+$ e.s.\ of $^{76}$Se, a lower half-life limit of $7.5\times10^{23}$~y at 90\% CL was achieved., Comment: 16 pages, 11 figures

Published
2020
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40. $\alpha$-event Characterization and Rejection in Point-Contact HPGe Detectors

Author

The MAJORANA Collaboration, 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., Drobizhev, A., Edwards, T. R., Edwins, D. W., Efremenko, Yu., 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., Kim, I., Kouzes, R. T., Lopez, A. M., López-Castaño, J. M., Martin, E. L., Martin, R. D., Massarczyk, R., Meijer, S. J., Mertens, S., Myslik, J., Oli, T. K., Othman, G., Pettus, W., Poon, A. W. P., Radford, D. C., Rager, J., Reine, A. L., Rielage, K., Ruof, N. W., Saykı, B., Schönert, S., Stortini, M. J., Tedeschi, D., Varner, R. L., Vasilyev, S., Wilkerson, J. F., Willers, M., Wiseman, C., Xu, W., Yu, C. -H., and Zhu, B. X.

Subjects
Physics - Instrumentation and Detectors, High Energy Physics - Experiment, Nuclear Experiment
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 $\alpha$ 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 ($0\nu\beta\beta$) in $^{76}$Ge. $\alpha$ 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 $\alpha$ identification, reliably identifying $\alpha$ background events on the passivated surface of the detector. We demonstrate effective rejection of all surface $\alpha$ 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 $0\nu\beta\beta$ region of interest window by an order of magnitude in the MAJORANA DEMONSTRATOR, and will be used in the upcoming LEGEND-200 experiment., Comment: Accepted for publication in European Journal of Physics C

Published
2020
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41. Initial results from the New Horizons exploration of 2014 MU69, a small Kuiper Belt Object

Author

Stern, S. A., Weaver, H. A., Spencer, J. R., Olkin, C. B., Gladstone, G. R., Grundy, W. M., Moore, J. M., Cruikshank, D. P., Elliott, H. A., McKinnon, W. B., Parker, J. Wm., Verbiscer, A. J., Young, L. A., Aguilar, D. A., Albers, J. M., Andert, T., Andrews, J. P., Bagenal, F., Banks, M. E., Bauer, B. A., Bauman, J. A., Bechtold, K. E., Beddingfield, C. B., Behrooz, N., Beisser, K. B., Benecchi, S. D., Bernardoni, E., Beyer, R. A., Bhaskaran, S., Bierson, C. J., Binzel, R. P., Birath, E. M., Bird, M. K., Boone, D. R., Bowman, A. F., Bray, V. J., Britt, D. T., Brown, L. E., Buckley, M. R., Buie, M. W., Buratti, B. J., Burke, L. M., Bushman, S. S., Carcich, B., Chaikin, A. L., Chavez, C. L., Cheng, A. F., Colwell, E. J., Conard, S. J., Conner, M. P., Conrad, C. A., Cook, J. C., Cooper, S. B., Custodio, O. S., Ore, C. M. Dalle, Deboy, C. C., Dharmavaram, P., Dhingra, R. D., Dunn, G. F., Earle, A. M., Egan, A. F., Eisig, J., El-Maarry, M. R., Engelbrecht, C., Enke, B. L., Ercol, C. J., Fattig, E. D., Ferrell, C. L., Finley, T. J., Firer, J., Fischetti, J., Folkner, W. M., Fosbury, M. N., Fountain, G. H., Freeze, J. M., Gabasova, L., Glaze, L. S., Green, J. L., Griffith, G. A., Guo, Y., Hahn, M., Hals, D. W., Hamilton, D. P., Hamilton, S. A., Hanley, J. J., Harch, A., Harmon, K. A., Hart, H. M., Hayes, J., Hersman, C. B., Hill, M. E., Hill, T. A., Hofgartner, J. D., Holdridge, M. E., Horányi, M., Hosadurga, A., Howard, A. D., Howett, C. J. A., Jaskulek, S. E., Jennings, D. E., Jensen, J. R., Jones, M. R., Kang, H. K., Katz, D. J., Kaufmann, D. E., Kavelaars, J. J., Keane, J. T., Keleher, G. P., Kinczyk, M., Kochte, M. C., Kollmann, P., Krimigis, S. M., Kruizinga, G. L., Kusnierkiewicz, D. Y., Lahr, M. S., Lauer, T. R., Lawrence, G. B., Lee, J. E., Lessac-Chenen, E. J., Linscott, I. R., Lisse, C. M., Lunsford, A. W., Mages, D. M., Mallder, V. A., Martin, N. P., May, B. H., McComas, D. J., McNutt, R. L., Mehoke, Jr. D. S., Mehoke, T. S., Nelson, D. S., Nguyen, H. D., Núñez, J. I., Ocampo, A. C., Owen, W. M., Oxton, G. K., Parker, A. H., Pätzold, M., Pelgrift, J. Y., Pelletier, F. J., Pineau, J. P., Piquette, M. R., Porter, S. B., Protopapa, S., Quirico, E., Redfern, J. A., Regiec, A. L., Reitsema, H. J., Reuter, D. C., Richardson, D. C., Riedel, J. E., Ritterbush, M. A., Robbins, S. J., Rodgers, D. J., Rogers, G. D., Rose, D. M., Rosendall, P. E., Runyon, K. D., Ryschkewitsch, M. G., Saina, M. M., Salinas, M. J., Schenk, P. M., Scherrer, J. R., Schlei, W. R., Schmitt, B., Schultz, D. J., Schurr, D. C., Scipioni, F., Sepan, R. L., Shelton, R. G., Showalter, M. R., Simon, M., Singer, K. N., Stahlheber, E. W., Stanbridge, D. R., Stansberry, J. A., Steffl, A. J., Strobel, D. F., Stothoff, M. M., Stryk, T., Stuart, J. R., Summers, M. E., Tapley, M. B., Taylor, A., Taylor, H. W., Tedford, R. M., Throop, H. B., Turner, L. S., Umurhan, O. M., Van Eck, J., Velez, D., Versteeg, M. H., Vincent, M. A., Webbert, R. W., Weidner, S. E., Weigle II, G. E., Wendel, J. R., White, O. L., Whittenburg, K. E., Williams, B. G., Williams, K. E., Williams, S. P., Winters, H. L., Zangari, A. M., and Zurbuchen, T. H.

Subjects
Astrophysics - Earth and Planetary Astrophysics
Abstract

The Kuiper Belt is a distant region of the Solar System. On 1 January 2019, the New Horizons spacecraft flew close to (486958) 2014 MU69, a Cold Classical Kuiper Belt Object, a class of objects that have never been heated by the Sun and are therefore well preserved since their formation. Here we describe initial results from these encounter observations. MU69 is a bi-lobed contact binary with a flattened shape, discrete geological units, and noticeable albedo heterogeneity. However, there is little surface color and compositional heterogeneity. No evidence for satellites, ring or dust structures, gas coma, or solar wind interactions was detected. By origin MU69 appears consistent with pebble cloud collapse followed by a low velocity merger of its two lobes., Comment: 43 pages, 8 figure

Published
2020
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42. ADC Nonlinearity Correction for the MAJORANA DEMONSTRATOR

Author

Abgrall, N., Allmond, J. M., Arnquist, I. J., Avignone III, F. T., Barabash, A. S., Barton, C. J., Bertrand, F. E., Bos, B., Busch, M., Buuck, M., Caldwell, T. S., Campbell, C. M., Chan, Y-D., Christofferson, C. D., Chu, P. -H., Clark, M. L., Crawford, H. L., 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., Lopez, A. M., Lopez-Castano, J. M., Martin, E. L., Martin, R. D., Massarczyk, R., Meijer, S. J., Mertens, S., Myslik, J., Oli, T. K., Othman, G., Pettus, W., Poon, A. W. P., Radford, D. C., Rager, J., Reine, A. L., Rielage, K., Ruof, N. W., Stortini, M. J., Tedeschi, D., Varner, R. L., Vasilyev, S., White, B. R., Wilkerson, J. F., Wiseman, C., Xu, W., Yu, C. -H., Zhu, B. X., and Shanks, B.

Subjects
Physics - Instrumentation and Detectors, Nuclear Experiment
Abstract

Imperfections in analog-to-digital conversion (ADC) cannot be ignored when signal digitization requirements demand both wide dynamic range and high resolution, as is the case for the Majorana Demonstrator 76Ge neutrinoless double beta decay search. Enabling the experiment's high-resolution spectral analysis and efficient pulse shape discrimination required careful measurement and correction of ADC nonlinearites. A simple measurement protocol was developed that did not require sophisticated equipment or lengthy data taking campaigns. A slope-dependent hysteresis was observed and characterized. A correction applied to digitized waveforms prior to signal processing reduced the differential and integral nonlinearites by an order of magnitude, eliminating these as dominant contributions to the systematic energy uncertainty at the double-beta decay Q value.

Published
2020
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43. Constraints on the Emission of Gamma Rays from M31 with HAWC

Author

HAWC Collaboration, Albert, A., Alfaro, R., Alvarez, C., Arteaga-Velázquez, J. C., Arunbabu, K. P., Rojas, D. Avila, Solares, H. A. Ayala, Belmont-Moreno, E., BenZvi, S. Y., Brisbois, C., Caballero-Mora, K. S., Capistrán, T., Carramiñana, A., Casanova, S., Cotti, U., Cotzomi, J., de León, S. Coutiño, De la Fuente, E., de León, C., Dichiara, S., Dingus, B. L., DuVernois, M. A., Engel, K., Espinoza, C., Fleischhack, H., Fraija, N., Galván-Gámez, A., García-Aguilar, D., García-González, J. A., Garfias, F., González, M. M., Goodman, J. A., Harding, J. P., Hernandez, S., Hona, B., Huang, D., Hueyotl-Zahuantitla, F., Hüntemeyer, P., Iriarte, A., Jardin-Blicq, A., Joshi, V., Kieda, D., Lee, W. H., Vargas, H. León, Longinotti, A. L., Luis-Raya, G., Malone, K., Marinelli, S. S., Martinez, O., Martinez-Castellanos, I., Martínez-Castro, J., Matthews, J. A., Miranda-Romagnoli, P., Morales-Soto, J. A., Moreno, E., Mostafá, M., Nayerhoda, A., Nellen, L., Newbold, M., Noriega-Papaqui, R., Peisker, A., Pérez-Pérez, E. G., Ren, Z., Rho, C. D., Rosa-González, D., Rosenberg, M., Rubenzahl, R., Salazar, H., Greus, F. Salesa, Sandoval, A., Schneider, M., Sinnis, G., Smith, A. J., Springer, R. W., Surajbali, P., Tabachnick, E., Tibolla, O., Tollefson, K., Torres, I., Villaseñor, L., Wood, J., Yapici, T., Zepeda, A., and Zhou, H.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

Cosmic rays, along with stellar radiation and magnetic fields, are known to make up a significant fraction of the energy density of galaxies such as the Milky Way. When cosmic rays interact in the interstellar medium, they produce gamma-ray emission which provides an important indication of how the cosmic rays propagate. Gamma rays from the Andromeda Galaxy (M31), located 785 kpc away, provide a unique opportunity to study cosmic-ray acceleration and diffusion in a galaxy with a structure and evolution very similar to the Milky Way. Using 33 months of data from the High Altitude Water Cherenkov Observatory, we search for TeV gamma rays from the galactic plane of M31. We also investigate past and present evidence of galactic activity in M31 by searching for Fermi Bubble-like structures above and below the galactic nucleus. No significant gamma-ray emission is observed, so we use the null result to compute upper limits on the energy density of cosmic rays $>10$ TeV in M31. The computed upper limits are approximately ten times higher than expected from the extrapolation of the Fermi LAT results., Comment: Accepted for publication in ApJ

Published
2020
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44. ADC Nonlinearity Correction for the Majorana Demonstrator

Author

Abgrall, N, Allmond, JM, Arnquist, IJ, Avignone, FT, Barabash, AS, Barton, CJ, Bertrand, FE, Bos, B, Busch, M, Buuck, M, Caldwell, TS, Campbell, CM, Chan, Y-D, Christofferson, CD, Chu, Pinghan, Clark, ML, Crawford, HL, 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, Lopez, AM, Lopez-Castano, 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, Stortini, MJ, Tedeschi, D, Varner, RL, Vasilyev, S, White, BR, Wilkerson, JF, Wiseman, C, Xu, W, Yu, C-H, Zhu, BX, and Shanks, B

Subjects
Nuclear and Plasma Physics, Synchrotrons and Accelerators, Physical Sciences, Gamma-ray detectors, neutrinoless double-beta decay, physics.ins-det, nucl-ex, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Other Physical Sciences, Biomedical Engineering, Nuclear & Particles Physics, Nuclear and plasma physics
Abstract

Imperfections in analog-to-digital conversion (ADC) cannot be ignored when signal digitization requirements demand both wide dynamic range and high resolution, as is the case for the Majorana Demonstrator 76Ge neutrinoless double-beta decay search. Enabling the experiment's high-resolution spectral analysis and efficient pulse shape discrimination required careful measurement and correction of ADC nonlinearities. A simple measurement protocol was developed that did not require sophisticated equipment or lengthy data-taking campaigns. A slope-dependent hysteresis was observed and characterized. A correction applied to digitized waveforms prior to signal processing reduced the differential and integral nonlinearities by an order of magnitude, eliminating these as dominant contributions to the systematic energy uncertainty at the double-beta decay Q value.

Published
2021

45. Search for double- β decay of Ge 76 to excited states of Se 76 with 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, YD, Christofferson, CD, Chu, PH, Clark, ML, Cuesta, C, Detwiler, JA, Drobizhev, A, Edwards, TR, Edwins, DW, Efremenko, Y, Ejiri, H, Elliott, SR, Gilliss, T, 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, Lopez, AM, López-Castaño, JM, Martin, EL, Martin, RD, Massarczyk, R, Meijer, SJ, Mertens, S, Myslik, J, Oli, TK, Othman, G, Paudel, LS, Pettus, W, Poon, AWP, Radford, DC, Reine, AL, Rielage, K, Ruof, NW, Saykl, B, Stortini, MJ, Tedeschi, D, Varner, RL, Vasilyev, S, Wilkerson, JF, Wiseman, C, Xu, W, Yu, CH, and Zhu, BX

Abstract

The majorana demonstrator is a neutrinoless double-β decay search consisting of a low-background modular array of high-purity germanium detectors, ∼2/3 of which are enriched to 88% in Ge76. The experiment is also searching for double-beta decay of Ge76 to excited states (e.s.) in Se76. Ge76 can decay into three daughter states of Se76, with clear event signatures consisting of a ββ-decay followed by the prompt emission of one or two γ rays. This results with high probability in multi-detector coincidences. The granularity of the demonstrator detector array enables powerful discrimination of this event signature from backgrounds. Using 41.9 kg yr of isotopic exposure, the demonstrator has set world leading limits for each e.s. decay of Ge76, with 90% CL lower half-life limits in the range of (0.75-4.0)×1024 yr. In particular, for the 2ν transition to the first 0+ e.s. of Se76, a lower half-life limit of 7.5×1023 yr at 90% CL was achieved.

Published
2021

46. Search for double-β decay of Ge76 to excited states of Se76 with 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, Drobizhev, A, Edwards, TR, Edwins, DW, Efremenko, Yu, Ejiri, H, Elliott, SR, Gilliss, T, 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, Lopez, AM, López-Castaño, JM, Martin, EL, Martin, RD, Massarczyk, R, Meijer, SJ, Mertens, S, Myslik, J, Oli, TK, Othman, G, Paudel, LS, Pettus, W, Poon, AWP, Radford, DC, Reine, AL, Rielage, K, Ruof, NW, Saykı, B, Stortini, MJ, 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

The majorana demonstrator is a neutrinoless double-β decay search consisting of a low-background modular array of high-purity germanium detectors, ∼2/3 of which are enriched to 88% in Ge76. The experiment is also searching for double-beta decay of Ge76 to excited states (e.s.) in Se76. Ge76 can decay into three daughter states of Se76, with clear event signatures consisting of a ββ-decay followed by the prompt emission of one or two γ rays. This results with high probability in multi-detector coincidences. The granularity of the demonstrator detector array enables powerful discrimination of this event signature from backgrounds. Using 41.9 kg yr of isotopic exposure, the demonstrator has set world leading limits for each e.s. decay of Ge76, with 90% CL lower half-life limits in the range of (0.75-4.0)×1024 yr. In particular, for the 2ν transition to the first 0+ e.s. of Se76, a lower half-life limit of 7.5×1023 yr at 90% CL was achieved.

Published
2021

47. Video-Worked Examples to Support the Development of Elementary Students' Science Process Skills: A Case Study in an Inquiry Activity on Electrical Circuits

Author

Solé-Llussà, A., Aguilar, D., and Ibáñez, M.

Abstract

Background: Scientific inquiry is a widely accepted methodology to promote science process skills. In inquiry activities, students develop their understanding by addressing questions, performing scientific research and interpreting results derived from their research. Developing these science skills to perform scientific inquiries is considered a learning objective in primary science education. Although this methodology yields good results, it can be too cognitively demanding for inexperienced students. Guides are therefore needed to support the development of novel inquirer activities. Purpose: In the present work, a didactic strategy based on video-worked examples is proposed for guiding the inquiry process in an elementary education classroom. Sample: This study included 30 elementary school students in the fifth and sixth grade from one rural school in Catalonia (eastern Spain). Design and method: The present work is a case study in which a quantitative method is applied to achieve the research objectives. Six open-ended questions were used to analyse the performance of the different science process skills. Results: Results confirm that the strategy based on the use of video-worked examples to support an inquiry activity provides students with a structure for the inquiry process, and in particular, improve their questioning, collection, processing and analysing skills. These data reinforce the idea that offering supports and instructions renders an opportunity to practise science process skills and improve the students' understanding and application of these abilities. Moreover, video-worked examples supported transferring scientific skills to other scientific contexts. Conclusions: The use of video-worked examples as a didactic strategy has a positive impact on the students' inquiry behavior. This strategy promoted positive classroom dynamics reflected in improved students' autonomy, collaborative work and motivation when performing an inquiry activity.

Published
2022
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48. A Low Energy Rare Event Search with the Majorana Demonstrator

Author

MAJORANA Collaboration, Wiseman, C., Arnquist, I. J., Avignone III, F. T., Barabash, A. S., Barton, C. J., Bertrand, F. 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., 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., Lopez, A. M., Lopez-Castano, J. M., Martin, E. L., Martin, R. D., Massarczyk, R., Meijer, S. J., Mertens, S., Myslik, J., Oli, T. K., Othman, G., Pettus, W., Poon, A. W. P., Radford, D. C., Rager, J., Reine, A. L., Rielage, K., Ruof, N. W., Sayki, B., Stortini, M. J., Tedeschi, D., Varner, R. L., Wilkerson, J. F., Xu, W., Yu, C. -H., and Zhu, B. X.

Subjects
Nuclear Experiment, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

The MAJORANA DEMONSTRATOR is sensitive to rare events near its energy threshold, including bosonic dark matter, solar axions, and lightly ionizing particles. In this analysis, a novel training set of low energy small-angle Compton scatter events is used to determine the efficiency of pulse shape analysis cuts, and we present updated bosonic dark matter and solar axion results from an 11.17 kg-y dataset using a 5 keV analysis threshold., Comment: 4 pages, 4 figures. Proceedings of the 16th International Conference on Topics in Astroparticle and Underground Physics (TAUP 2019), September 9-13, 2019, Toyama, Japan

Published
2019
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49. Results of the MAJORANA DEMONSTRATOR's Search for Double-Beta Decay of $^{76}$Ge to Excited States of $^{76}$Se

Author

Guinn, I. S., Arnquist, I. J., Avignone III, F. T., Barabash, A. S., Barton, C. J., Bertrand, F. 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., Drobizhev, A., Edwins, D. W., Efremenko, Yu., Ejiri, H., Elliott, S. R., Gilliss, T., Giovanetti, G. K., Green, M. P., Gruszko, J., 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., Lopez, A. M., no, J. M. López-Casta, Martin, E. L., Martin, R. D., Massarczyk, R., Meijer, S. J., Mertens, S., Myslik, J., Oli, T. K., Othman, G., Pettus, W., Poon, A. W. P., Radford, D. C., Rager, J., Reine, A. L., Rielage, K., Ruof, N. W., Stortini, M. J., Tedeschi, D., Varner, R. L., Wilkerson, J. F., Wiseman, C., Xu, W., Yu, C. -H., and Zhu, B. X.

Subjects
Nuclear Experiment
Abstract

The MAJORANA DEMONSTRATOR is searching for double-beta decay of $^{76}$Ge to excited states (E.S.) in $^{76}$Se using a modular array of high purity Germanium detectors. $^{76}$Ge can decay into three E.S.s of $^{76}$Se. The E.S. decays have a clear event signature consisting of a $\beta\beta$-decay with the prompt emission of one or two $\gamma$-rays, resulting in with high probability in a multi-site event. The granularity of the DEMONSTRATOR detector array enables powerful discrimination of this event signature from backgrounds. Using 21.3 kg-y of isotopic exposure, the DEMONSTRATOR has set world leading limits for each E.S. decay, with 90% CL lower half-life limits in the range of $(0.56-2.1)\cdot10^{24}$ y. In particular, for the $2\nu$ transition to the first $0^+$ E.S. of $^{76}$Se, a lower half-life limit of $0.68\cdot10^{24}$ at 90% CL was achieved.

Published
2019
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50. A Search for Neutrinoless Double-Beta Decay in $^{76}$Ge with 26 kg-yr of Exposure from the MAJORANA DEMONSTRATOR

Author

Alvis, S. I., Arnquist, I. J., Avignone III, F. T., Barabash, A. S., Barton, C. J., Basu, V., Bertrand, F. E., Bos, B., Busch, M., Buuck, M., Caldwell, T. S., Chan, Y-D., Christofferson, C. D., Chu, P. -H., Cuesta, C., Detwiler, J. A., 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., Hehn, L., Henning, R., Aguilar, D. Hervas, Hoppe, E. W., Howe, M. A., Kidd, M. F., Konovalov, S. I., Kouzes, R. T., Lopez, A. M., Martin, R. D., Massarczyk, R., Meijer, S. J., Mertens, S., Myslik, J., Othman, G., Pettus, W., Piliounis, A., Poon, A. W. P., Radford, D. C., Rager, J., Reine, A. L., Rielage, K., Ruof, N. W., Shanks, B., Shirchenko, M., Tedeschi, D., Varner, R. L., Vasilyev, S., White, B. R., Wilkerson, J. F., Wiseman, C., Xu, W., Yakushev, E., Yu, C. -H., Yumatov, V., Zhitnikov, I., and Zhu, B. X.

Subjects
Nuclear Experiment, High Energy Physics - Experiment
Abstract

The MAJORANA Collaboration is operating an array of high purity Ge detectors to search for the neutrinoless double-beta decay of $^{76}$Ge. The MAJORANA DEMONSTRATOR consists of 44.1 kg of Ge detectors (29.7 kg enriched to 88% in $^{76}$Ge) split between two modules constructed from ultra-clean materials. Both modules are contained in a low-background shield at the Sanford Underground Research Facility in Lead, South Dakota. We present updated results on the search for neutrinoless double-beta decay in $^{76}$Ge with $26.0\pm0.5$ kg-yr of enriched exposure. With the DEMONSTRATOR's unprecedented energy resolution of 2.53 keV FWHM at $Q_{\beta\beta}$, we observe one event in the region of interest with 0.65 events expected from the estimated background, resulting in a lower limit on the $^{76}$Ge neutrinoless double-beta decay half-life of $2.7\times10^{25}$ yr (90% CL) with a median sensitivity of $4.8\times10^{25}$ yr (90% CL). Depending on the matrix elements used, a 90% CL upper limit on the effective Majorana neutrino mass in the range of 200-433 meV is obtained. The measured background in the low-background configurations is $11.9\pm2.0$ counts/(FWHM t yr)., Comment: 11 pages, 11 figures

Published
2019
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