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212 results on '"Caldwell, T. S."'

1. 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

2. Measurement of the electric potential and the magnetic field in the shifted analysing plane of the KATRIN experiment

Author

Aker, M., Batzler, D., Beglarian, A., Behrens, J., Beisenkötter, J., Biassoni, M., Bieringer, B., Biondi, Y., Block, F., Bobien, S., Böttcher, M., Bornschein, B., Bornschein, L., Caldwell, T. S., Carminati, M., Chatrabhuti, A., Chilingaryan, S., Daniel, B. A., Debowski, K., Descher, M., Barrero, D. Díaz, Doe, P. J., Dragoun, O., Drexlin, G., Edzards, F., Eitel, K., Ellinger, E., Engel, R., Enomoto, S., Felden, A., Fengler, C., Fiorini, C., Formaggio, J. A., Forstner, C., Fränkle, F. M., Gauda, K., Gavin, A. S., Gil, W., Glück, F., Grössle, R., Gumbsheimer, R., Hannen, V., Hasselmann, L., Haußmann, N., Helbing, K., Heyns, S., Hickford, S., Hiller, R., Hillesheimer, D., Hinz, D., Höhn, T., Huber, A., Jansen, A., Karl, C., Kellerer, J., Khosonthongkee, K., Köhler, C., Köllenberger, L., Kopmann, A., Kovač, N., Krause, H., La Cascio, L., Lasserre, T., Lauer, J., Le, T. L., Lebeda, O., Lehnert, B., Li, G., Lokhov, A., Machatschek, M., Mark, M., Marsteller, A., Martin, E. L., McMichael, K., Melzer, C., Mertens, S., Mohanty, S., Mostafa, J., Müller, K., Nava, A., Neumann, H., Niemes, S., Parno, D. S., Pavan, M., Pinsook, U., Poon, A. W. P., Poyato, J. M. L., Pozzi, S., Priester, F., Ráliš, J., Ramachandran, S., Robertson, R. G. H., Rodenbeck, C., Röllig, M., Sack, R., Saenz, A., Salomon, R., Schäfer, P., Schlösser, M., Schlösser, K., Schlüter, L., Schneidewind, S., Schrank, M., Schürmann, J., Schütz, A. K., Schwemmer, A., Schwenck, A., Šefčík, M., Siegmann, D., Simon, F., Spanier, F., Spreng, D., Sreethawong, W., Steidl, M., Štorek, J., Stribl, X., Sturm, M., Suwonjandee, N., Jerome, N. Tan, Telle, H. H., Thorne, L. A., Thümmler, T., Titov, N., Tkachev, I., Urban, K., Valerius, K., Vénos, D., Weinheimer, C., Welte, S., Wendel, J., Wiesinger, C., Wilkerson, J. F., Wolf, J., Wüstling, S., Wydra, J., Xu, W., Zadorozhny, S., and Zeller, G.

Subjects
Physics - Instrumentation and Detectors
Abstract

The projected sensitivity of the effective electron neutrino-mass measurement with the KATRIN experiment is below 0.3 eV (90 % CL) after five years of data acquisition. The sensitivity is affected by the increased rate of the background electrons from KATRIN's main spectrometer. A special shifted-analysing-plane (SAP) configuration was developed to reduce this background by a factor of two. The complex layout of electromagnetic fields in the SAP configuration requires a robust method of estimating these fields. We present in this paper a dedicated calibration measurement of the fields using conversion electrons of gaseous $^\mathrm{83m}$Kr, which enables the neutrino-mass measurements in the SAP configuration., Comment: 19 pages, 11 figures

Published
2024

3. Direct neutrino-mass measurement based on 259 days of KATRIN data

Author

Aker, M., Batzler, D., Beglarian, A., Behrens, J., Beisenkötter, J., Biassoni, M., Bieringer, B., Biondi, Y., Block, F., Bobien, S., Böttcher, M., Bornschein, B., Bornschein, L., Caldwell, T. S., Carminati, M., Chatrabhuti, A., Chilingaryan, S., Daniel, B. A., Debowski, K., Descher, M., Barrero, D. Díaz, Doe, P. J., Dragoun, O., Drexlin, G., Edzards, F., Eitel, K., Ellinger, E., Engel, R., Enomoto, S., Felden, A., Fengler, C., Fiorini, C., Formaggio, J. A., Forstner, C., Fränkle, F. M., Gauda, K., Gavin, A. S., Gil, W., Glück, F., Grohmann, S., Grössle, R., Gumbsheimer, R., Gutknecht, N., Hannen, V., Hasselmann, L., Haußmann, N., Helbing, K., Henke, H., Heyns, S., Hickford, S., Hiller, R., Hillesheimer, D., Hinz, D., Höhn, T., Huber, A., Jansen, A., Karl, C., Kellerer, J., Khosonthongkee, K., Kleifges, M., Klein, M., Kohpeiß, J., Köhler, C., Köllenberger, L., Kopmann, A., Kovač, N., Kovalík, A., Krause, H., La Cascio, L., Lasserre, T., Lauer, J., Le, T., Lebeda, O., Lehnert, B., Li, G., Lokhov, A., Machatschek, M., Mark, M., Marsteller, A., Martin, E. L., Melzer, C., Mertens, S., Mohanty, S., Mostafa, J., Müller, K., Nava, A., Neumann, H., Niemes, S., Onillon, A., Parno, D. S., Pavan, M., Pinsook, U., Poon, A. W. P., Poyato, J. M. Lopez, Pozzi, S., Priester, F., Ráliš, J., Ramachandran, S., Robertson, R. G. H., Rodenbeck, C., Röllig, M., Röttele, C., Ryšavý, M., Sack, R., Saenz, A., Salomon, R., Schäfer, P., Schlösser, M., Schlösser, K., Schlüter, L., Schneidewind, S., Schnurr, U., Schrank, M., Schürmann, J., Schütz, A., Schwemmer, A., Schwenck, A., Šefčík, M., Siegmann, D., Simon, F., Spanier, F., Spreng, D., Sreethawong, W., Steidl, M., Štorek, J., Stribl, X., Sturm, M., Suwonjandee, N., Jerome, N. Tan, Telle, H. H., Thorne, L. A., Thümmler, T., Tirolf, S., Titov, N., Tkachev, I., Urban, K., Valerius, K., Vénos, D., Weinheimer, C., Welte, S., Wendel, J., Wiesinger, C., Wilkerson, J. F., Wolf, J., Wüstling, S., Wydra, J., Xu, W., Zadorozhny, S., and Zeller, G.

Subjects
Nuclear Experiment, High Energy Physics - Experiment
Abstract

The fact that neutrinos carry a non-vanishing rest mass is evidence of physics beyond the Standard Model of elementary particles. Their absolute mass bears important relevance from particle physics to cosmology. In this work, we report on the search for the effective electron antineutrino mass with the KATRIN experiment. KATRIN performs precision spectroscopy of the tritium $\beta$-decay close to the kinematic endpoint. Based on the first five neutrino-mass measurement campaigns, we derive a best-fit value of $m_\nu^{2} = {-0.14^{+0.13}_{-0.15}}~\mathrm{eV^2}$, resulting in an upper limit of $m_\nu < {0.45}~\mathrm{eV}$ at 90 % confidence level. With six times the statistics of previous data sets, amounting to 36 million electrons collected in 259 measurement days, a substantial reduction of the background level and improved systematic uncertainties, this result tightens KATRIN's previous bound by a factor of almost two., Comment: 61 pages, 20 figures, 2 tables

Published
2024

4. 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

5. 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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6. 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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7. 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

8. 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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9. 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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10. 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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11. Search for keV-scale Sterile Neutrinos with first KATRIN Data

Author

Aker, M., Batzler, D., Beglarian, A., Behrens, J., Berlev, A., Besserer, U., Bieringer, B., Block, F., Bobien, S., Bornschein, B., Bornschein, L., Böttcher, M., Brunst, T., Caldwell, T. S., Carney, R. M. D., Chilingaryan, S., Choi, W., Debowski, K., Descher, M., Barrero, D. Díaz, Doe, P. J., Dragoun, O., Drexlin, G., Edzards, F., Eitel, K., Ellinger, E., Engel, R., Enomoto, S., Felden, A., Formaggio, J. A., Fränkle, F. M., Franklin, G. B., Friedel, F., Fulst, A., Gauda, K., Gavin, A. S., Gil, W., Glück, F., Grössle, R., Gumbsheimer, R., Hannen, V., Haußmann, N., Helbing, K., Hickford, S., Hiller, R., Hillesheimer, D., Hinz, D., Höhn, T., Houdy, T., Huber, A., Jansen, A., Karl, C., Kellerer, J., Kleifges, M., Klein, M., Köhler, C., Köllenberger, L., Kopmann, A., Korzeczek, M., Kovalík, A., Krasch, B., Krause, H., La Cascio, L., Lasserre, T., Le, T. L., Lebeda, O., Lehnert, B., Lokhov, A., Machatschek, M., Malcherek, E., Mark, M., Marsteller, A., Martin, E. L., Melzer, C., Mertens, S., Mostafa, J., Müller, K., Neumann, H., Niemes, S., Oelpmann, P., Parno, D. S., Poon, A. W. P., Poyato, J. M. L., Priester, F., Ráliš, J., Ramachandran, S., Robertson, R. G. H., Rodejohann, W., Rodenbeck, C., Röllig, M., Röttele, C., Ryšavý, M., Sack, R., Saenz, A., Salomon, R., Schäfer, P., Schimpf, L., Schlösser, M., Schlösser, K., Schlüter, L., Schneidewind, S., Schrank, M., Schwemmer, A., Šefčík, M., Sibille, V., Siegmann, D., Slezák, M., Spanier, F., Steidl, M., Sturm, M., Telle, H. H., Thorne, L. A., Thümmler, T., Titov, N., Tkachev, I., Urban, K., Valerius, K., Vénos, D., Hernández, A. P. Vizcaya, Weinheimer, C., Welte, S., Wendel, J., Wetter, M., Wiesinger, C., Wilkerson, J. F., Wolf, J., Wüstling, S., Wydra, J., Xu, W., Zadoroghny, S., and Zeller, G.

Subjects
Nuclear Experiment
Abstract

In this work we present a keV-scale sterile-neutrino search with the first tritium data of the KATRIN experiment, acquired in the commissioning run in 2018. KATRIN performs a spectroscopic measurement of the tritium $\beta$-decay spectrum with the main goal of directly determining the effective electron anti-neutrino mass. During this commissioning phase a lower tritium activity facilitated the search for sterile neutrinos with a mass of up to $1.6\, \mathrm{keV}$. We do not find a signal and set an exclusion limit on the sterile-to-active mixing amplitude of down to $\sin^2\theta < 5\cdot10^{-4}$ ($95\,\%$ C.L.), improving current laboratory-based bounds in the sterile-neutrino mass range between 0.1 and $1.0\, \mathrm{keV}$.

Published
2022

12. Search for Lorentz-Invariance Violation with the first KATRIN data

Author

Aker, M., Batzler, D., Beglarian, A., Behrens, J., Berlev, A., Besserer, U., Bieringer, B., Block, F., Bobien, S., Bornschein, B., Bornschein, L., Böttcher, M., Brunst, T., Caldwell, T. S., Carney, R. M. D., Chilingaryan, S., Choi, W., Debowski, K., Deffert, M., Descher, M., Barrero, D. Díaz, Doe, P. J., Dragoun, O., Drexlin, G., Edzards, F., Eitel, K., Ellinger, E., Engel, R., Enomoto, S., Felden, A., Formaggio, J. A., Fränkle, F. M., Franklin, G. B., Friedel, F., Fulst, A., Gauda, K., Gavin, A. S., Gil, W., Glück, F., Grössle, R., Gumbsheimer, R., Hannen, V., Haußmann, N., Helbing, K., Hickford, S., Hiller, R., Hillesheimer, D., Hinz, D., Höhn, T., Houdy, T., Huber, A., Jansen, A., Karl, C., Kellerer, J., Kleifges, M., Klein, M., Köhler, C., Köllenberger, L., Kopmann, A., Korzeczek, M., Kovalík, A., Krasch, B., Krause, H., La Cascio, L., Lasserre, T., Le, T. L., Lebeda, O., Lehnert, B., Lokhov, A., Machatschek, M., Malcherek, E., Mark, M., Marsteller, A., Martin, E. L., Melzer, C., Mertens, S., Mostafa, J., Müller, K., Neumann, H., Niemes, S., Oelpmann, P., Parno, D. S., Poon, A. W. P., Poyato, J. M. L., Priester, F., Ráliš, J., Ramachandran, S., Robertson, R. G. H., Rodejohann, W., Rodenbeck, C., Röllig, M., Röttele, C., Ryšavý, M., Sack, R., Saenz, A., Salomon, R., Schäfer, P., Schimpf, L., Schlösser, M., Schlösser, K., Schlüter, L., Schneidewind, S., Schrank, M., Schwemmer, A., Šefčík, M., Sibille, V., Siegmann, D., Slezák, M., Spanier, F., Steidl, M., Sturm, M., Telle, H. H., Thorne, L. A., Thümmler, T., Titov, N., Tkachev, I., Urban, K., Valerius, K., Vénos, D., Hernández, A. P. Vizcaya, Weinheimer, C., Welte, S., Wendel, J., Wetter, M., Wickles, J., Wiesinger, C., Wilkerson, J. F., Wolf, J., Wüstling, S., Wydra, J., Xu, W., Zadoroghny, S., and Zeller, G.

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

Some extensions of the Standard Model of Particle Physics allow for Lorentz invariance and Charge-Parity-Time (CPT)-invariance violations. In the neutrino sector strong constraints have been set by neutrino-oscillation and time-of-flight experiments. However, some Lorentz-invariance-violating parameters are not accessible via these probes. In this work, we focus on the parameters $(a_{\text{of}}^{(3)})_{00}$, $(a_{\text{of}}^{(3)})_{10}$ and $(a_{\text{of}}^{(3)})_{11}$ which would manifest themselves in a non-isotropic beta-decaying source as a sidereal oscillation and an overall shift of the spectral endpoint. Based on the data of the first scientific run of the KATRIN experiment, we set the first limit on $\left|(a_{\text{of}}^{(3)})_{11}\right|$ of $< 3.7\cdot10^{-6}$ GeV at 90\% confidence level. Moreover, we derive new constraints on $(a_{\text{of}}^{(3)})_{00}$ and $(a_{\text{of}}^{(3)})_{10}$.

Published
2022
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13. 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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14. 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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15. 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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16. KATRIN: Status and Prospects for the Neutrino Mass and Beyond

Author

Aker, M., Balzer, M., Batzler, D., Beglarian, A., Behrens, J., Berlev, A., Besserer, U., Biassoni, M., Bieringer, B., Block, F., Bobien, S., Bombelli, L., Bormann, D., Bornschein, B., Bornschein, L., Böttcher, M., Brofferio, C., Bruch, C., Brunst, T., Caldwell, T. S., Carminati, M., Carney, R. M. D., Chilingaryan, S., Choi, W., Cremonesi, O., Debowski, K., Descher, M., Barrero, D. Díaz, Doe, P. J., Dragoun, O., Drexlin, G., Edzards, F., Eitel, K., Ellinger, E., Engel, R., Enomoto, S., Felden, A., Fink, D., Fiorini, C., Formaggio, J. A., Forstner, C., Fränkle, F. M., Franklin, G. B., Friedel, F., Fulst, A., Gauda, K., Gavin, A. S., Gil, W., Glück, F., Grande, A., Grössle, R., Gugiatti, M., Gumbsheimer, R., Hannen, V., Hartmann, J., Haußmann, N., Helbing, K., Hickford, S., Hiller, R., Hillesheimer, D., Hinz, D., Höhn, T., Houdy, T., Huber, A., Jansen, A., Karl, C., Kellerer, J., King, P., Kleifges, M., Klein, M., Köhler, C., Köllenberger, L., Kopmann, A., Korzeczek, M., Kovalík, A., Krasch, B., Krause, H., Lasserre, T., La Cascio, L., Lebeda, O., Lechner, P., Lehnert, B., Le, T. L., Lokhov, A., Machatschek, M., Malcherek, E., Manfrin, D., Mark, M., Marsteller, A., Martin, E. L., Mazzola, E., Melzer, C., Mertens, S., Mostafa, J., Müller, K., Nava, A., Neumann, H., Niemes, S., Oelpmann, P., Onillon, A., Parno, D. S., Pavan, M., Pigliafreddo, A., Poon, A. W. P., Poyato, J. M. L., Pozzi, S., Priester, F., Puritscher, M., Radford, D. C., Ráliš, J., Ramachandran, S., Robertson, R. G. H., Rodejohann, W., Rodenbeck, C., Röllig, M., Röttele, C., Ryšavý, M., Sack, R., Saenz, A., Salomon, R. W. J., Schäfer, P., Schimpf, L., Schlösser, K., Schlösser, M., Schlüter, L., Schneidewind, S., Schrank, M., Schütz, A. K., Schwemmer, A., Sedlak, A., Šefčík, M., Sibille, V., Siegmann, D., Slezák, M., Spanier, F., Spreng, D., Steidl, M., Sturm, M., Telle, H. H., Thorne, L. A., Thümmler, T., Titov, N., Tkachev, I., Trigilio, P., Urban, K., Valerius, K., Vénos, D., Hernández, A. P. Vizcaya, Voigt, P., Weinheimer, C., Weiss, E., Welte, S., Wendel, J., Wiesinger, C., Wilkerson, J. F., Wolf, J., Wunderl, L., Wüstling, S., Wydra, J., Xu, W., Zadoroghny, S., and Zeller, G.

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

The Karlsruhe Tritium Neutrino (KATRIN) experiment is designed to measure a high-precision integral spectrum of the endpoint region of T2 beta decay, with the primary goal of probing the absolute mass scale of the neutrino. After a first tritium commissioning campaign in 2018, the experiment has been regularly running since 2019, and in its first two measurement campaigns has already achieved a sub-eV sensitivity. After 1000 days of data-taking, KATRIN's design sensitivity is 0.2 eV at the 90% confidence level. In this white paper we describe the current status of KATRIN; explore prospects for measuring the neutrino mass and other physics observables, including sterile neutrinos and other beyond-Standard-Model hypotheses; and discuss research-and-development projects that may further improve the KATRIN sensitivity., Comment: Contribution to Snowmass 2021. 70 pages excluding references; 35 figures. Author list updated June 2023

Published
2022
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17. 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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18. New Constraint on the Local Relic Neutrino Background Overdensity with the First KATRIN Data Runs

Author

Aker, M., Batzler, D., Beglarian, A., Behrens, J., Berlev, A., Besserer, U., Bieringer, B., Block, F., Bobien, S., Bornschein, B., Bornschein, L., Böttcher, M., Brunst, T., Caldwell, T. S., Carney, R. M. D., Chilingaryan, S., Choi, W., Debowski, K., Descher, M., Barrero, D. Díaz, Doe, P. J., Dragoun, O., Drexlin, G., Edzards, F., Eitel, K., Ellinger, E., Engel, R., Enomoto, S., Felden, A., Formaggio, J. A., Fränkle, F. M., Franklin, G. B., Friedel, F., Fulst, A., Gauda, K., Gavin, A. S., Gil, W., Glück, F., Grössle, R., Gumbsheimer, R., Hannen, V., Haußmann, N., Helbing, K., Hickford, S., Hiller, R., Hillesheimer, D., Hinz, D., Höhn, T., Houdy, T., Huber, A., Jansen, A., Karl, C., Kellerer, F., Kellerer, J., Kleifges, M., Klein, M., Köhler, C., Köllenberger, L., Kopmann, A., Korzeczek, M., Kovalík, A., Krasch, B., Krause, H., La Cascio, L., Lasserre, T., Le, T. L., Lebeda, O., Lehnert, B., Lokhov, A., Machatschek, M., Malcherek, E., Mark, M., Marsteller, A., Martin, E. L., Melzer, C., Mertens, S., Mostafa, J., Müller, K., Neumann, H., Niemes, S., Oelpmann, P., Parno, D. S., Poon, A. W. P., Poyato, J. M. L., Priester, F., Ráliš, J., Ramachandran, S., Robertson, R. G. H., Rodejohann, W., Rodenbeck, C., Röllig, M., Röttele, C., Ryšavý, M., Sack, R., Saenz, A., Salomon, R., Schäfer, P., Schimpf, L., Schlösser, M., Schlösser, K., Schlüter, L., Schneidewind, S., Schrank, M., Schwemmer, A., Šefčík, M., Sibille, V., Siegmann, D., Slezák, M., Spanier, F., Steidl, M., Sturm, M., Telle, H. H., Thorne, L. A., Thümmler, T., Titov, N., Tkachev, I., Urban, K., Valerius, K., Vénos, D., Hernández, A. P. Vizcaya, Weinheimer, C., Welte, S., Wendel, J., Wetter, M., Wiesinger, C., Wilkerson, J. F., Wolf, J., Wüstling, S., Wydra, J., Xu, W., Zadoroghny, S., and Zeller, G.

Subjects
Nuclear Experiment, Astrophysics - Cosmology and Nongalactic Astrophysics, High Energy Physics - Experiment
Abstract

We report on the direct cosmic relic neutrino background search from the first two science runs of the KATRIN experiment in 2019. Beta-decay electrons from a high-purity molecular tritium gas source are analyzed by a high-resolution MAC-E filter around the kinematic endpoint at 18.57 keV. The analysis is sensitive to a local relic neutrino overdensity of 9.7e10 (1.1e11) at a 90% (95%) confidence level. A fit of the integrated electron spectrum over a narrow interval around the kinematic endpoint accounting for relic neutrino captures in the Tritium source reveals no significant overdensity. This work improves the results obtained by the previous kinematic neutrino mass experiments at Los Alamos and Troitsk. We furthermore update the projected final sensitivity of the KATRIN experiment to <1e10 at 90% confidence level, by relying on updated operational conditions., Comment: 7 pages, 7 figures

Published
2022
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19. 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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20. Improved eV-scale Sterile-Neutrino Constraints from the Second KATRIN Measurement Campaign

Author

Aker, M., Batzler, D., Beglarian, A., Behrens, J., Berlev, A., Besserer, U., Bieringer, B., Block, F., Bobien, S., Bornschein, B., Bornschein, L., Böttcher, M., Brunst, T., Caldwell, T. S., Carney, R. M. D., Chilingaryan, S., Choi, W., Debowski, K., Descher, M., Barrero, D. Díaz, Doe, P. J., Dragoun, O., Drexlin, G., Edzards, F., Eitel, K., Ellinger, E., Engel, R., Enomoto, S., Felden, A., Formaggio, J. A., Fränkle, F. M., Franklin, G. B., Friedel, F., Fulst, A., Gauda, K., Gavin, A. S., Gil, W., Glück, F., Grössle, R., Gumbsheimer, R., Hannen, V., Haußmann, N., Helbing, K., Hickford, S., Hiller, R., Hillesheimer, D., Hinz, D., Höhn, T., Houdy, T., Huber, A., Jansen, A., Karl, C., Kellerer, J., Kleifges, M., Klein, M., Köhler, C., Köllenberger, L., Kopmann, A., Korzeczek, M., Kovalík, A., Krasch, B., Krause, H., La Cascio, L., Lasserre, T., Le, T. L., Lebeda, O., Lehnert, B., Lokhov, A., Machatschek, M., Malcherek, E., Mark, M., Marsteller, A., Martin, E. L., Melzer, C., Mertens, S., Mostafa, J., Müller, K., Neumann, H., Niemes, S., Oelpmann, P., Parno, D. S., Poon, A. W. P., Poyato, J. M. L., Priester, F., Ráliš, J., Ramachandran, S., Robertson, R. G. H., Rodejohann, W., Rodenbeck, C., Röllig, M., Röttele, C., Ryšavý, M., Sack, R., Saenz, A., Salomon, R., Schäfer, P., Schimpf, L., Schlösser, M., Schlösser, K., Schlüter, L., Schneidewind, S., Schrank, M., Schwemmer, A., Šefčík, M., Sibille, V., Siegmann, D., Slezák, M., Spanier, F., Steidl, M., Sturm, M., Telle, H. H., Thorne, L. A., Thümmler, T., Titov, N., Tkachev, I., Urban, K., Valerius, K., Vénos, D., Hernández, A. P. Vizcaya, Weinheimer, C., Welte, S., Wendel, J., Wetter, M., Wiesinger, C., Wilkerson, J. F., Wolf, J., Wüstling, S., Wydra, J., Xu, W., Zadoroghny, S., and Zeller, G.

Subjects
High Energy Physics - Experiment
Abstract

We present the results of the light sterile neutrino search from the second KATRIN measurement campaign in 2019. Approaching nominal activity, $3.76 \times 10^6$ tritium $\beta$-electrons are analyzed in an energy window extending down to $40\,$eV below the tritium endpoint at $E_0 = 18.57\,$keV. We consider the $3\nu+1$ framework with three active and one sterile neutrino flavor. The analysis is sensitive to a fourth mass eigenstate $m_4^2\lesssim1600\,$eV$^2$ and active-to-sterile mixing $|U_{e4}|^2 \gtrsim 6 \times 10^{-3}$. As no sterile-neutrino signal was observed, we provide improved exclusion contours on $m_4^2$ and $|U_{e4}|^2$ at $95\,$% C.L. Our results supersede the limits from the Mainz and Troitsk experiments. Furthermore, we are able to exclude the large $\Delta m_{41}^2$ solutions of the reactor antineutrino and gallium anomalies to a great extent. The latter has recently been reaffirmed by the BEST collaboration and could be explained by a sterile neutrino with large mixing. While the remaining solutions at small $\Delta m_{41}^2$ are mostly excluded by short-baseline reactor experiments, KATRIN is the only ongoing laboratory experiment to be sensitive to relevant solutions at large $\Delta m_{41}^2$ through a robust spectral shape analysis., Comment: 14 pages, 8 figures, 2 tables

Published
2022
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21. 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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22. 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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23. 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

24. First direct neutrino-mass measurement with sub-eV sensitivity

Author

Aker, M., Beglarian, A., Behrens, J., Berlev, A., Besserer, U., Bieringer, B., Block, F., Bornschein, B., Bornschein, L., Böttcher, M., Brunst, T., Caldwell, T. S., Carney, R. M. D., La Cascio, L., Chilingaryan, S., Choi, W., Debowski, K., Deffert, M., Descher, M., Barrero, D. Díaz, Doe, P. J., Dragoun, O., Drexlin, G., Eitel, K., Ellinger, E., Engel, R., Enomoto, S., Felden, A., Formaggio, J. A., Fränkle, F. M., Franklin, G. B., Friedel, F., Fulst, A., Gauda, K., Gil, W., Glück, F., Grössle, R., Gumbsheimer, R., Gupta, V., Höhn, T., Hannen, V., Haußmann, N., Helbing, K., Hickford, S., Hiller, R., Hillesheimer, D., Hinz, D., Houdy, T., Huber, A., Jansen, A., Karl, C., Kellerer, F., Kellerer, J., Klein, M., Köhler, C., Köllenberger, L., Kopmann, A., Korzeczek, M., Kovalík, A., Krasch, B., Krause, H., Kunka, N., Lasserre, T., Le, T. L., Lebeda, O., Lehnert, B., Lokhov, A., Machatschek, M., Malcherek, E., Mark, M., Marsteller, A., Martin, E. L., Melzer, C., Menshikov, A., Mertens, S., Mostafa, J., Müller, K., Niemes, S., Oelpmann, P., Parno, D. S., Poon, A. W. P., Poyato, J. M. L., Priester, F., Röllig, M., Röttele, C., Robertson, R. G. H., Rodejohann, W., Rodenbeck, C., Ryšavý, M., Sack, R., Saenz, A., Schäfer, P., Schaller, A., Schimpf, L., Schlösser, K., Schlösser, M., Schlüter, L., Schneidewind, S., Schrank, M., Schulz, B., Schwemmer, A., Šefčík, M., Sibille, V., Siegmann, D., Slezák, M., Steidl, M., Sturm, M., Sun, M., Tcherniakhovski, D., Telle, H. H., Thorne, L. A., Thümmler, T., Titov, N., Tkachev, I., Urban, K., Valerius, K., Vénos, D., Hernández, A. P. Vizcaya, Weinheimer, C., Welte, S., Wendel, J., Wilkerson, J. F., Wolf, J., Wüstling, S., Xu, W., Yen, Y. -R., Zadoroghny, S., and Zeller, G.

Subjects
High Energy Physics - Experiment, Nuclear Experiment
Abstract

We report the results of the second measurement campaign of the Karlsruhe Tritium Neutrino (KATRIN) experiment. KATRIN probes the effective electron anti-neutrino mass, $m_{\nu}$, via a high-precision measurement of the tritium $\beta$-decay spectrum close to its endpoint at $18.6\,\mathrm{keV}$. In the second physics run presented here, the source activity was increased by a factor of 3.8 and the background was reduced by $25\,\%$ with respect to the first campaign. A sensitivity on $m_{\nu}$ of $0.7\,\mathrm{eV/c^2}$ at $90\,\%$ confidence level (CL) was reached. This is the first sub-eV sensitivity from a direct neutrino-mass experiment. The best fit to the spectral data yields $m_{\nu}^2 = (0.26\pm0.34)\,\mathrm{eV^4/c^4}$, resulting in an upper limit of $m_{\nu}<0.9\,\mathrm{eV/c^2}$ ($90\,\%$ CL). By combining this result with the first neutrino mass campaign, we find an upper limit of $m_{\nu}<0.8\,\mathrm{eV/c^2}$ ($90\,\%$ CL)., Comment: 19 pages, 10 figures, 5 tables

Published
2021

25. Precision measurement of the electron energy-loss function in tritium and deuterium gas for the KATRIN experiment

Author

Aker, M., Beglarian, A., Behrens, J., Berlev, A., Besserer, U., Bieringer, B., Block, F., Bornschein, B., Bornschein, L., Böttcher, M., Brunst, T., Caldwell, T. S., Carney, R. M. D., Chilingaryan, S., Choi, W., Debowski, K., Deffert, M., Descher, M., Barrero, D. Díaz, Doe, P. J., Dragoun, O., Drexlin, G., Edzards, F., Eitel, K., Ellinger, E., Miniawy, A. El, Engel, R., Enomoto, S., Felden, A., Formaggio, J. A., Fränkle, F. M., Franklin, G. B., Friedel, F., Fulst, A., Gauda, K., Gil, W., Glück, F., Groh, S., Grössle, R., Gumbsheimer, R., Hannen, V., Haußmann, N., Heizmann, F., Helbing, K., Hickford, S., Hiller, R., Hillesheimer, D., Hinz, D., Höhn, T., Houdy, T., Huber, A., Jansen, A., Karl, C., Kellerer, J., Kleesiek, M., Klein, M., Köhler, C., Köllenberger, L., Kopmann, A., Korzeczek, M., Kovalík, A., Krasch, B., Krause, H., Kunka, N., Lasserre, T., La Cascio, L., Lebeda, O., Lehnert, B., Le, T. L., Lokhov, A., Machatschek, M., Malcherek, E., Mark, M., Marsteller, A., Martin, E. L., Meier, M., Melzer, C., Menshikov, A., Mertens, S., Mostafa, J., Müller, K., Niemes, S., Oelpmann, P., Parno, D. S., Poon, A. W. P., Poyato, J. M. L., Priester, F., Ranitzsch, P. C. -O., Robertson, R. G. H., Rodejohann, W., Rodenbeck, C., Röllig, M., Röttele, C., Ryšavý, M., Sack, R., Saenz, A., Schäfer, P., Schaller, A., Schimpf, L., Schlösser, K., Schlösser, M., Schlüter, L., Schneidewind, S., Schrank, M., Schulz, B., Schwachtgen, C., Šefčík, M., Seitz-Moskaliuk, H., Sibille, V., Siegmann, D., Slezák, M., Steidl, M., Sturm, M., Sun, M., Tcherniakhovski, D., Telle, H. H., Thorne, L. A., Thümmler, T., Titov, N., Tkachev, I., Trost, N., Urban, K., Valerius, K., Vénos, D., Hernández, A. P. Vizcaya, Weinheimer, C., Welte, S., Wendel, J., Wilkerson, J. F., Wolf, J., Wüstling, S., Xu, W., Yen, Y. -R., Zadoroghny, S., and Zeller, G.

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

The KATRIN experiment is designed for a direct and model-independent determination of the effective electron anti-neutrino mass via a high-precision measurement of the tritium $\beta$-decay endpoint region with a sensitivity on $m_\nu$ of 0.2$\,$eV/c$^2$ (90% CL). For this purpose, the $\beta$-electrons from a high-luminosity windowless gaseous tritium source traversing an electrostatic retarding spectrometer are counted to obtain an integral spectrum around the endpoint energy of 18.6$\,$keV. A dominant systematic effect of the response of the experimental setup is the energy loss of $\beta$-electrons from elastic and inelastic scattering off tritium molecules within the source. We determined the \linebreak energy-loss function in-situ with a pulsed angular-selective and monoenergetic photoelectron source at various tritium-source densities. The data was recorded in integral and differential modes; the latter was achieved by using a novel time-of-flight technique. We developed a semi-empirical parametrization for the energy-loss function for the scattering of 18.6-keV electrons from hydrogen isotopologs. This model was fit to measurement data with a 95% T$_2$ gas mixture at 30$\,$K, as used in the first KATRIN neutrino mass analyses, as well as a D$_2$ gas mixture of 96% purity used in KATRIN commissioning runs. The achieved precision on the energy-loss function has abated the corresponding uncertainty of $\sigma(m_\nu^2)<10^{-2}\,\mathrm{eV}^2$ [arXiv:2101.05253] in the KATRIN neutrino-mass measurement to a subdominant level., Comment: 12 figures, 18 pages; to be submitted to EPJ C

Published
2021
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26. The Design, Construction, and Commissioning of the KATRIN Experiment

Author

Aker, M., Altenmüller, K., Amsbaugh, J. F., Arenz, M., Babutzka, M., Bast, J., Bauer, S., Bechtler, H., Beck, M., Beglarian, A., Behrens, J., Bender, B., Berendes, R., Berlev, A., Besserer, U., Bettin, C., Bieringer, B., Blaum, K., Block, F., Bobien, S., Bohn, J., Bokeloh, K., Bolz, H., Bornschein, B., Bornschein, L., Böttcher, M., Bouquet, H., Boyd, N. M., Brunst, T., Burritt, T. H., Caldwell, T. S., Chaoui, Z., Chilingaryan, S., Choi, W., Corona, T. J., Cox, G. A., Debowski, K., Deffert, M., Descher, M., Barrero, D. Díaz, Doe, P. J., Dragoun, O., Drexlin, G., Dunmore, J. A., Dyba, S., Edzards, F., Eichelhardt, F., Eitel, K., Ellinger, E., Engel, R., Enomoto, S., Erhard, M., Eversheim, D., Fedkevych, M., Felden, A., Fischer, S., Formaggio, J. A., Fränkle, F. M., Franklin, G. B., Frenzel, H., Friedel, F., Fulst, A., Gauda, K., Gehring, R., Gil, W., Glück, F., Görhardt, S., Grimm, J., Grohmann, S., Groh, S., Grössle, R., Gumbsheimer, R., Hackenjos, M., Häßler, D., Hannen, V., Harms, F., Harper, G. C., Hartmann, J., Haußmann, N., Heizmann, F., Helbing, K., Held, M., Hickford, S., Hilk, D., Hillen, B., Hiller, R., Hillesheimer, D., Hinz, D., Höhn, T., Holzmann, S., Horn, S., Hötzel, M., Houdy, T., Howe, M. A., Huber, A., James, T., Jansen, A., Kaiser, M., Karl, C., Kazachenko, O., Kellerer, J., Kippenbrock, L., Kleesiek, M., Kleifges, M., Kleinfeller, J., Klein, M., Köllenberger, L., Kopmann, A., Korzeczek, M., Kosmider, A., Kovalík, A., Krasch, B., Krause, H., Kraus, M., Kuckert, L., Kumb, A., Kunka, N., Lasserre, T., La Cascio, L., Lebeda, O., Leber, M. L., Lehnert, B., Leiber, B., Letnev, J., Lewis, R. J., Le, T. L., Lichter, S., Lokhov, A., Poyato, J. M. Lopez, Machatschek, M., Malcherek, E., Mark, M., Marsteller, A., Martin, E. L., Mehret, K., Meloni, M., Melzer, C., Menshikov, A., Mertens, S., Minter, L. I., Monreal, B., Mostafa, J., Müller, K., Myers, A. W., Naumann, U., Neumann, H., Niemes, S., Oelpmann, P., Off, A., Ortjohann, H. -W., Osipowicz, A., Ostrick, B., Parno, D. S., Peterson, D. A., Plischke, P., Poon, A. W. P., Prall, M., Priester, F., Ranitzsch, P. C. -O., Reich, J., Renschler, P., Rest, O., Rinderspacher, R., Robertson, R. G. H., Rodejohann, W., Rodenbeck, C., Rohr, P., Röllig, M., Röttele, C., Rupp, S., Ryšavý, M., Sack, R., Saenz, A., Sagawe, M., Schäfer, P., Schaller, A., Schimpf, L., Schlösser, K., Schlösser, M., Schlüter, L., Schneidewind, S., Schön, H., Schönung, K., Schrank, M., Schulz, B., Schwarz, J., Šefčík, M., Seitz-Moskaliuk, H., Seller, W., Sibille, V., Siegmann, D., Slezák, M., Spanier, F., Steidl, M., Sturm, M., Sun, M., Tcherniakhovski, D., Telle, H. H., Thorne, L. A., Thümmler, T., Titov, N., Tkachev, I., Trost, N., Valerius, K., VanDevender, B. A., Van Wechel, T. D., Vénos, D., Verbeek, A., Vianden, R., Hernández, A. P. Vizcaya, Vogt, K., Wall, B. L., Wandkowsky, N., Weber, M., Weingardt, H., Weinheimer, C., Weiss, C., Welte, S., Wendel, J., Wierman, K. J., Wilkerson, J. F., Wolf, J., Wüstling, S., Xu, W., Yen, Y. -R., Zacher, M., Zadoroghny, S., Zboril, M., and Zeller, G.

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

The KArlsruhe TRItium Neutrino (KATRIN) experiment, which aims to make a direct and model-independent determination of the absolute neutrino mass scale, is a complex experiment with many components. More than 15 years ago, we published a technical design report (TDR) [https://publikationen.bibliothek.kit.edu/270060419] to describe the hardware design and requirements to achieve our sensitivity goal of 0.2 eV at 90% C.L. on the neutrino mass. Since then there has been considerable progress, culminating in the publication of first neutrino mass results with the entire beamline operating [arXiv:1909.06048]. In this paper, we document the current state of all completed beamline components (as of the first neutrino mass measurement campaign), demonstrate our ability to reliably and stably control them over long times, and present details on their respective commissioning campaigns., Comment: Added missing acknowledgement, corrected performance statement in chapter 4.2.5, updated author list and references

Published
2021
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27. Analysis methods for the first KATRIN neutrino-mass measurement

Author

Aker, M., Altenmüller, K., Beglarian, A., Behrens, J., Berlev, A., Besserer, U., Bieringer, B., Blaum, K., Block, F., Bornschein, B., Bornschein, L., Böttcher, M., Brunst, T., Caldwell, T. S., La Cascio, L., Chilingaryan, S., Choi, W., Barrero, D. Díaz, Debowski, K., Deffert, M., Descher, M., Doe, P. J., Dragoun, O., Drexlin, G., Dyba, S., Edzards, F., Eitel, K., Ellinger, E., Engel, R., Enomoto, S., Fedkevych, M., Felden, A., Formaggio, J. A., Fränkle, F. M., Franklin, G. B., Friedel, F., Fulst, A., Gauda, K., Gil, W., Glück, F., Grössle, R., Gumbsheimer, R., Höhn, T., Hannen, V., Haußmann, N., Helbing, K., Hickford, S., Hiller, R., Hillesheimer, D., Hinz, D., Houdy, T., Huber, A., Jansen, A., Köllenberger, L., Karl, C., Kellerer, J., Kippenbrock, L., Klein, M., Kopmann, A., Korzeczek, M., Kovalík, A., Krasch, B., Krause, H., Lasserre, T., Le, T. L., Lebeda, O., Lehnert, B., Lokhov, A., Poyato, J. M. Lopez, Müller, K., Machatschek, M., Malcherek, E., Mark, M., Marsteller, A., Martin, E. L., Melzer, C., Mertens, S., Niemes, S., Oelpmann, P., Osipowicz, A., Parno, D. S., Poon, A. W. P., Priester, F., Röllig, M., Röttele, C., Rest, O., Robertson, R. G. H., Rodenbeck, C., Ryšavý, M., Sack, R., Saenz, A., Schaller, A., Schäfer, P., Schimpf, L., Schlösser, K., Schlösser, M., Schlüter, L., Schrank, M., Schulz, B., Šefčík, M., Seitz-Moskaliuk, H., Sibille, V., Siegmann, D., Slezák, M., Spanier, F., Steidl, M., Sturm, M., Sun, M., Telle, H. H., Thümmler, T., Thorne, L. A., Titov, N., Tkachev, I., Trost, N., Vénos, D., Valerius, K., Hernández, A. P. Vizcaya, Wüstling, S., Weber, M., Weinheimer, C., Weiss, C., Welte, S., Wendel, J., Wilkerson, J. F., Wolf, J., Xu, W., Yen, Y. -R., Zadoroghny, S., and Zeller, G.

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

We report on the data set, data handling, and detailed analysis techniques of the first neutrino-mass measurement by the Karlsruhe Tritium Neutrino (KATRIN) experiment, which probes the absolute neutrino-mass scale via the $\beta$-decay kinematics of molecular tritium. The source is highly pure, cryogenic T$_2$ gas. The $\beta$ electrons are guided along magnetic field lines toward a high-resolution, integrating spectrometer for energy analysis. A silicon detector counts $\beta$ electrons above the energy threshold of the spectrometer, so that a scan of the thresholds produces a precise measurement of the high-energy spectral tail. After detailed theoretical studies, simulations, and commissioning measurements, extending from the molecular final-state distribution to inelastic scattering in the source to subtleties of the electromagnetic fields, our independent, blind analyses allow us to set an upper limit of 1.1 eV on the neutrino-mass scale at a 90\% confidence level. This first result, based on a few weeks of running at a reduced source intensity and dominated by statistical uncertainty, improves on prior limits by nearly a factor of two. This result establishes an analysis framework for future KATRIN measurements, and provides important input to both particle theory and cosmology., Comment: 36 pages with 26 figures. Accepted to Phys. Rev. D

Published
2021
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28. Bound on 3+1 active-sterile neutrino mixing from the first four-week science run of KATRIN

Author

Aker, M., Altenmueller, K., Beglarian, A., Behrens, J., Berlev, A., Besserer, U., Bieringer, B., Blaum, K., Block, F., Bornschein, B., Bornschein, L., Boettcher, M., Brunst, T., Caldwell, T. S., La Cascio, L., Chilingaryan, S., Choi, W., Barrero, D. Diaz, Debowski, K., Deffert, M., Descher, M., Doe, P. J., Dragoun, O., Drexlin, G., Dyba, S., Edzards, F., Eitel, K., Ellinger, E., Engel, R., Enomoto, S., Felden, M. Fedkevych A., Formaggio, J. A., Fraenkle, F. M., Franklin, G. B., Friedel, F., Fulst, A., Gauda, K., Gil, W., Glueck, F., Groessle, R., Gumbsheimer, R., Hoehn, T., Hannen, V., Haussmann, N., Helbing, K., Hickford, S., Hiller, R., Hillesheimer, D., Hinz, D., Houdy, T., Huber, A., Jansen, A., Koellenberger, L., Karl, C., Kellerer, J., Kippenbrock, L., Klein, M., Kopmann, A., Korzeczek, M., Kovalik, A., Krasch, B., Krause, H., Lasserre, T., Le, T. L., Lebeda, O., Guennic, N. Le, Lehnert, B., Lokhov, A., Poyato, J. M. Lopez, Mueller, K., Machatschek, M., Malcherek, E., Mark, M., Marsteller, A., Martin, E. L., Melzer, C., Mertens, S., Niemes, S., Oelpmann, P., Osipowicz, A., Parno, D. S., Poon, A. W. P., Priester, F., Roellig, M., Roettele, C., Rest, O., Robertson, R. G. H., Rodenbeck, C., Rysavy, M., Sack, R., Saenz, A., Schaller, A., Schaefer, P., Schimpf, L., Schloesser, M., Schloesser, K., Schlueter, L., Schrank, M., Schulz, B., Sefcik, M., Seitz-Moskaliuk, H., Sibille, V., Siegmann, D., Slezak, M., Spanier, F., Steidl, M., Sturm, M., Sun, M., Telle, H. H., Thuemmler, T., Thorne, L. A., Titov, N., Tkachev, I., Trost, N., Venos, D., Valerius, K., Hernandez, A. P. Vizcaya, Wuestling, S., Weber, M., Weinheimer, C., Weiss, C., Welte, S., Wendel, J., Wilkerson, J. F., Wolf, J., Xu, W., Yen, Y. -R., Zadoroghny, S., and Zeller, G.

Subjects
High Energy Physics - Experiment, Nuclear Experiment
Abstract

We report on the light sterile neutrino search from the first four-week science run of the KATRIN experiment in~2019. Beta-decay electrons from a high-purity gaseous molecular tritium source are analyzed by a high-resolution MAC-E filter down to 40 eV below the endpoint at 18.57 keV. We consider the framework with three active neutrinos and one sterile neutrino of mass $m_{4}$. The analysis is sensitive to a fourth mass state $m^2_{4} \lesssim$ 1000 eV$^2$ and to active-to-sterile neutrino mixing down to $|U_{e4}|^2 \gtrsim 2\cdot10^{-2}$. No significant spectral distortion is observed and exclusion bounds on the sterile mass and mixing are reported. These new limits supersede the Mainz results and improve the Troitsk bound for $m^2_{4} <$ 30 eV$^2$. The reactor and gallium anomalies are constrained for $ 100 < \Delta{m}^2_{41} < 1000$ eV$^2$., Comment: 8 pages, 4 figures

Published
2020
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29. 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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30. $\alpha$-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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31. 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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32. 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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33. 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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34. Suppression of Penning discharges between the KATRIN spectrometers

Author

Aker, M., Altenmüller, K., Beglarian, A., Behrens, J., Berlev, A., Besserer, U., Blaum, K., Block, F., Bobien, S., Bornschein, B., Bornschein, L., Bouquet, H., Brunst, T., Caldwell, T. S., Chilingaryan, S., Choi, W., Debowski, K., Deffert, M., Descher, M., Barrero, D. Díaz, Doe, P. J., Dragoun, O., Drexlin, G., Dyba, S., Eitel, K., Ellinger, E., Engel, R., Enomoto, S., Eversheim, D., Fedkevych, M., Felden, A., Formaggio, J. A., Fränkle, F., Franklin, G. B., Frankrone, H., Friedel, F., Fulst, A., Gauda, K., Gil, W., Glück, F., Grohmann, S., Grössle, R., Gumbsheimer, R., Hackenjos, M., Hannen, V., Hartmann, J., Haußmann, N., Heizmann, F., Heizmann, J., Helbing, K., Hickford, S., Hillesheimer, D., Hinz, D., Höhn, T., Holzapfel, B., Holzmann, S., Houdy, T., Jansen, A., Karl, C., Kellerer, J., Kernert, N., Kippenbrock, L., Klein, M., Köhler, C., Köllenberger, L., Kopmann, A., Korzeczek, M., Kovalík, A., Krasch, B., Krause, H., Kuffner, B., Kunka, N., Lasserre, T., La Cascio, L., Lebeda, O., Lehnert, B., Letnev, J., Leven, F., Le, T. L., Lichter, S., Lokhov, A., Machatschek, M., Malcherek, E., Marsteller, A., Martin, E. L., Melzer, C., Menshikov, A., Mertens, S., Monreal, B., Müller, K., Naumann, U., Neumann, H., Niemes, S., Noe, M., Ortjohann, H. -W., Osipowicz, A., Otten, E., Parno, D. S., Pollithy, A., Poon, A. W. P., Poyato, J. M. L., Priester, F., Ranitzsch, P. C. -O., Rest, O., Rinderspacher, R., Robertson, R. G. H., Rodenbeck, C., Rohr, P., Röllig, M., Röttele, C., Ryšavý, M., Sack, R., Saenz, A., Schäfer, P., Schimpf, L., Schlösser, K., Schlösser, M., Schlüter, L., Schrank, M., Schulz, B., Seitz-Moskaliuk, H., Seller, W., Sibille, V., Siegmann, D., Slezák, M., Spanier, F., Steidl, M., Steven, M., Sturm, M., Suesser, M., Sun, M., Tcherniakhovski, D., Telle, H. H., Thorne, L. A., Thümmler, T., Titov, N., Tkachev, I., Trost, N., Valerius, K., Vénos, D., Vianden, R., Hernández, A. P. Vizcaya, Weber, M., Weinheimer, C., Weiss, C., Welte, S., Wendel, J., Wilkerson, J. F., Wolf, J., Wüstling, S., Xu, W., Yen, Y. -R., Zadoroghny, S., and Zeller, G.

Subjects
Physics - Instrumentation and Detectors
Abstract

The KArlsruhe TRItium Neutrino experiment (KATRIN) aims to determine the effective electron (anti)neutrino mass with a sensitivity of $0.2\textrm{ eV/c}^2$ (90$\%$ C.L.) by precisely measuring the endpoint region of the tritium $\beta$-decay spectrum. It uses a tandem of electrostatic spectrometers working as MAC-E (magnetic adiabatic collimation combined with an electrostatic) filters. In the space between the pre-spectrometer and the main spectrometer, an unavoidable Penning trap is created when the superconducting magnet between the two spectrometers, biased at their respective nominal potentials, is energized. The electrons accumulated in this trap can lead to discharges, which create additional background electrons and endanger the spectrometer and detector section downstream. To counteract this problem, "electron catchers" were installed in the beamline inside the magnet bore between the two spectrometers. These catchers can be moved across the magnetic-flux tube and intercept on a sub-ms time scale the stored electrons along their magnetron motion paths. In this paper, we report on the design and the successful commissioning of the electron catchers and present results on their efficiency in reducing the experimental background., Comment: - 12 pages, 14 figures, LaTeX; typos corrected, references added; precised a few arguments, added additional discussions, results unchanged

Published
2019
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35. An improved upper limit on the neutrino mass from a direct kinematic method by KATRIN

Author

Aker, M., Altenmüller, K., Arenz, M., Babutzka, M., Barrett, J., Bauer, S., Beck, M., Beglarian, A., Behrens, J., Bergmann, T., Besserer, U., Blaum, K., Block, F., Bobien, S., Bokeloh, K., Bonn, J., Bornschein, B., Bornschein, L., Bouquet, H., Brunst, T., Caldwell, T. S., La Cascio, L., Chilingaryan, S., Choi, W., Corona, T. J., Debowski, K., Deffert, M., Descher, M., Doe, P. J., Dragoun, O., Drexlin, G., Dunmore, J. A., Dyba, S., Edzards, F., Eisenblätter, L., Eitel, K., Ellinger, E., Engel, R., Enomoto, S., Erhard, M., Eversheim, D., Fedkevych, M., Felden, A., Fischer, S., Flatt, B., Formaggio, J. A., Fränkle, F. M., Franklin, G. B., Frankrone, H., Friedel, F., Fuchs, D., Fulst, A., Furse, D., Gauda, K., Gemmeke, H., Gil, W., Glück, F., Görhardt, S., Groh, S., Grohmann, S., Grössle, R., Gumbsheimer, R., Minh, M. Ha, Hackenjos, M., Hannen, V., Harms, F., Hartmann, J., Haußmann, N., Heizmann, F., Helbing, K., Hickford, S., Hilk, D., Hillen, B., Hillesheimer, D., Hinz, D., Höhn, T., Holzapfel, B., Holzmann, S., Houdy, T., Howe, M. A., Huber, A., Jansen, A., Kaboth, A., Karl, C., Kazachenko, O., Kellerer, J., Kernert, N., Kippenbrock, L., Kleesiek, M., Klein, M., Köhler, C., Köllenberger, L., Kopmann, A., Korzeczek, M., Kosmider, A., Kovalí, A., Krasch, B., Kraus, M., Krause, H., Kuckert, L., Kuffner, B., Kunka, N., Lasserre, T., Le, T. L., Lebeda, O., Leber, M., Lehnert, B., Letnev, J., Leven, F., Lichter, S., Lobashev, V. M., Lokhov, A., Machatschek, M., Malcherek, E., Müller, K., Mark, M., Marsteller, A., Martin, E. L., Melzer, C., Menshikov, A., Mertens, S., Minter, L. I., Mirz, S., Monreal, B., Guzman, P. I. Morales, Naumann, U., Ndeke, W., Neumann, H., Niemes, S., Noe, M., Oblath, N. S., Ortjohann, H. -W., Osipowicz, A., Ostrick, B., Otten, E., Parno, D. S., Phillips II, D. G., Plischke, P., Pollithy, A., Poon, A. W. P., Pouryamout, J., Prall, M., Priester, F., Röllig, M., Röttele, C., Ranitzsch, P. C. -O., Rest, O., Rinderspacher, R., Robertson, R. G. H., Rodenbeck, C., Rohr, P., Roll, Ch., Rupp, S., Rysavy, M., Sack, R., Saenz, A., Schäfer, P., Schimpf, L., Schlösser, K., Schlösser, M., Schlüter, L., Schön, H., Schönung, K., Schrank, M., Schulz, B., Schwarz, J., Seitz-Moskaliuk, H., Seller, W., Sibille, V., Siegmann, D., Skasyrskaya, A., Slezak, M., Spalek, A., Spanier, F., Steidl, M., Steinbrink, N., Sturm, M., Suesser, M., Sun, M., Tcherniakhovski, D., Telle, H. H., Thümmler, T., Thorne, L. A., Titov, N., Tkachev, I., Trost, N., Urban, K., Venos, D., Valerius, K., VanDevender, B. A., Vianden, R., Hernandez, A. P. Vizcaya, Wall, B. L., Wüstling, S., Weber, M., Weinheimer, C., Weiss, C., Welte, S., Wendel, J., Wierman, K. J., Wilkerson, J. F., Wolf, J., Xu, W., Yen, Y. -R., Zacher, M., Zadorozhny, S., Zboril, M., and Zeller, G.

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

We report on the neutrino mass measurement result from the first four-week science run of the Karlsruhe Tritium Neutrino experiment KATRIN in spring 2019. Beta-decay electrons from a high-purity gaseous molecular tritium source are energy analyzed by a high-resolution MAC-E filter. A fit of the integrated electron spectrum over a narrow interval around the kinematic endpoint at 18.57 keV gives an effective neutrino mass square value of $(-1.0^{+0.9}_{-1.1})$ eV$^2$. From this we derive an upper limit of 1.1 eV (90$\%$ confidence level) on the absolute mass scale of neutrinos. This value coincides with the KATRIN sensitivity. It improves upon previous mass limits from kinematic measurements by almost a factor of two and provides model-independent input to cosmological studies of structure formation.

Published
2019
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36. First operation of the KATRIN experiment with tritium

Author

Aker, M., Altenmüller, K., Arenz, M., Baek, W. -J., Barrett, J., Beglarian, A., Behrens, J., Berlev, A., Besserer, U., Blaum, K., Block, F., Bobien, S., Bornschein, B., Bornschein, L., Bouquet, H., Brunst, T., Caldwell, T. S., Chilingaryan, S., Choi, W., Debowski, K., Deffert, M., Descher, M., Barrero, D. Díaz, Doe, P. J., Dragoun, O., Drexlin, G., Dyba, S., Edzards, F., Eitel, K., Ellinger, E., Engel, R., Enomoto, S., Eversheim, D., Fedkevych, M., Felden, A., Formaggio, J. A., Fränkle, F. M., Franklin, G. B., Frankrone, H., Friedel, F., Fuchs, D., Fulst, A., Gauda, K., Gil, W., Glück, F., Grohmann, S., Grössle, R., Gumbsheimer, R., Hackenjos, M., Hannen, V., Hartmann, J., Haußmann, N., Minh, M. Ha, Heizmann, F., Heizmann, J., Helbing, K., Hickford, S., Hillesheimer, D., Hinz, D., Höhn, T., Holzapfel, B., Holzmann, S., Houdy, T., Howe, M. A., Huber, A., Jansen, A., Karl, C., Kellerer, J., Kernert, N., Kippenbrock, L., Kleesiek, M., Klein, M., Köhler, C., Köllenberger, L., Kopmann, A., Korzeczek, M., Kovalík, A., Krasch, B., Krause, H., Kuffner, B., Kunka, N., Lasserre, T., La Cascio, L., Lebeda, O., Lebert, M., Lehnert, B., Letnev, J., Leven, F., Le, T. L., Lichter, S., Lokhov, A., Machatschek, M., Malcherek, E., Mark, M., Marsteller, A., Martin, E. L., Megas, F., Melzer, C., Menshikov, A., Mertens, S., Meier, M., Mirz, S., Monreal, B., Guzmán, P. I. Morales, Müller, K., Naumann, U., Neumann, H., Niemes, S., Noe, M., Off, A., Ortjohann, H. -W., Osipowicz, A., Otten, E., Parno, D. S., Pollithy, A., Poon, A. W. P., Poyato, J. M. L., Priester, F., Ranitzsch, P. C. -O., Rest, O., Rinderspacher, R., Robertson, R. G. H., Rodenbeck, C., Rohr, P., Röllig, M., Röttele, C., Ryšavý, M., Sack, R., Saenz, A., Schäfer, P., Schimpf, L., Schlösser, K., Schlösser, M., Schlüter, L., Schrank, M., Schulz, B., Seitz-Moskaliuk, H., Seller, W., Sibille, V., Siegmann, D., Slezák, M., Spanier, F., Steidl, M., Steven, M., Sturm, M., Suesser, M., Sun, M., Tcherniakhovski, D., Telle, H. H., Thorne, L. A., Thümmler, T., Titov, N., Tkachev, I., Trost, N., Urban, K., Valerius, K., Vénos, D., Vianden, R., Hernández, A. P. Vizcaya, Weber, M., Weinheimer, C., Weiss, C., Welte, S., Wendel, J., Wilkerson, J. F., Wolf, J., Wüstling, S., Xu, W., Yen, Y. -R., Zadorozhny, S., and Zeller, G.

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

The determination of the neutrino mass is one of the major challenges in astroparticle physics today. Direct neutrino mass experiments, based solely on the kinematics of beta-decay, provide a largely model-independent probe to the neutrino mass scale. The Karlsruhe Tritium Neutrino (KATRIN) experiment is designed to directly measure the effective electron antineutrino mass with a sensitivity of 0.2 eV 90% CL. In this work we report on the first operation of KATRIN with tritium which took place in 2018. During this commissioning phase of the tritium circulation system, excellent agreement of the theoretical prediction with the recorded spectra was found and stable conditions over a time period of 13 days could be established. These results are an essential prerequisite for the subsequent neutrino mass measurements with KATRIN in 2019.

Published
2019
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37. 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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38. Multi-site event discrimination for the MAJORANA DEMONSTRATOR

Author

Alvis, S. I., Arnquist, I. J., Avignone III, F. T., Barabash, A. S., Barton, C. J., Bertrand, F. E., Bos, B., Buuck, M., Caldwell, T. S., Chan, Y-D., Christofferson, C. D., Chu, P. -H., Cuesta, C., Detwiler, J. A., 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., Keeter, K. J., 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., Vasundhara, White, B. R., Wilkerson, J. F., Wiseman, C., Xu, W., Yakushev, E., Yu, C. -H., Yumatov, V., Zhitnikov, I., and Zhu, B. X.

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

The MAJORANA DEMONSTRATOR is searching for neutrinoless double-beta decay in 76Ge using arrays of point-contact germanium detectors operating at the Sanford Underground Research Facility. Background results in the neutrinoless double-beta decay region of interest from data taken during construction, commissioning, and the start of full operations have been recently published. A pulse shape analysis cut applied to achieve this result, named AvsE, is described in this paper. This cut is developed to remove events whose waveforms are typical of multi-site energy deposits while retaining (90 +/- 3.5)% of single-site events. This pulse shape discrimination is based on the relationship between the maximum current and energy, and tuned using 228Th calibration source data. The efficiency uncertainty accounts for variation across detectors, energy, and time, as well as for the position distribution difference between calibration and $0\nu\beta\beta$ events, established using simulations., Comment: 8 pages, 8 figures

Published
2019
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39. Search for keV-scale sterile neutrinos with the first KATRIN data

Author

Aker, M., Batzler, D., Beglarian, A., Behrens, J., Berlev, A., Besserer, U., Bieringer, B., Block, F., Bobien, S., Bornschein, B., Bornschein, L., Böttcher, M., Brunst, T., Caldwell, T. S., Chilingaryan, S., Choi, W., Debowski, K., Descher, M., Barrero, D. Díaz, Doe, P. J., Dragoun, O., Drexlin, G., Edzards, F., Eitel, K., Ellinger, E., Engel, R., Enomoto, S., Felden, A., Formaggio, J. A., Fränkle, F. M., Franklin, G. B., Friedel, F., Fulst, A., Gauda, K., Gavin, A. S., Gil, W., Glück, F., Grössle, R., Gumbsheimer, R., Hannen, V., Haußmann, N., Helbing, K., Hickford, S., Hiller, R., Hillesheimer, D., Hinz, D., Höhn, T., Houdy, T., Huber, A., Jansen, A., Karl, C., Kellerer, J., Kleifges, M., Klein, M., Köhler, C., Köllenberger, L., Kopmann, A., Korzeczek, M., Kovalík, A., Krasch, B., Krause, H., La Cascio, L., Lasserre, T., Le, T. L., Lebeda, O., Lehnert, B., Lokhov, A., Machatschek, M., Malcherek, E., Mark, M., Marsteller, A., Martin, E. L., Melzer, C., Mertens, S., Mostafa, J., Müller, K., Neumann, H., Niemes, S., Oelpmann, P., Parno, D. S., Poon, A. W. P., Poyato, J. M. L., Priester, F., Ráliš, J., Ramachandran, S., Robertson, R. G. H., Rodejohann, W., Rodenbeck, C., Röllig, M., Röttele, C., Ryšavý, M., Sack, R., Saenz, A., Salomon, R., Schäfer, P., Schimpf, L., Schlösser, M., Schlösser, K., Schlüter, L., Schneidewind, S., Schrank, M., Schwemmer, A., Šefǧík, M., Sibille, V., Siegmann, D., Slezák, M., Spanier, F., Steidl, M., Sturm, M., Telle, H. H., Thorne, L. A., Thümmler, T., Titov, N., Tkachev, I., Urban, K., Valerius, K., Vénos, D., Hernández, A. P. Vizcaya, Weinheimer, C., Welte, S., Wendel, J., Wetter, M., Wiesinger, C., Wilkerson, J. F., Wolf, J., Wüstling, S., Wydra, J., Xu, W., Zadoroghny, S., and Zeller, G.

Published
2023
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40. Recent results from the MAJORANA DEMONSTRATOR

Author

Myslik, J., Alvis, S. I., Arnquist, I. J., Avignone III, F. T., Barabash, A. S., Barton, C. J., Bertrand, F. E., Bode, T., Bos, B., Brudanin, V., Busch, M., Buuck, M., Caldwell, T. S., Chan, Y-D., Christofferson, C. D., Chu, P. -H., Cuesta, C., Detwiler, J. A., Dunagan, C., 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., Keeter, K. J., Kidd, M. F., Konovalov, S. I., Kouzes, R. T., Lopez, A. M., Martin, R. D., Massarczyk, R., Meijer, S. J., Mertens, S., 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., Vasundhara, White, B. R., Wilkerson, J. F., Wiseman, C., Xu, W., Yakushev, E., Yu, C. -H., Yumatov, V., Zhitnikov, I., and Zhu, B. X.

Subjects
Physics - Instrumentation and Detectors, Nuclear Experiment
Abstract

The MAJORANA DEMONSTRATOR is an experiment constructed to search for neutrinoless double-beta decay in $^{76}$Ge and to demonstrate the feasibility to deploy a large-scale experiment in a phased and modular fashion. It consists of two modules of natural and $^{76}$Ge-enriched germanium detectors totalling 44.1 kg, operating at the 4850' level of the Sanford Underground Research Facility in Lead, South Dakota, USA. Commissioning of the experiment began in June 2015, followed by data production with the full detector array in August 2016. The ultra-low background and record energy resolution achieved by the MAJORANA DEMONSTRATOR enable a sensitive neutrinoless double-beta decay search, as well as additional searches for physics beyond the Standard Model. I will discuss the design elements that enable these searches, along with the latest results, focusing on the neutrinoless double-beta decay search. I will also discuss the current status and the future plans of the MAJORANA DEMONSTRATOR, as well as the plans for a future tonne-scale $^{76}$Ge experiment., Comment: 4 pages. Proceedings of The 39th International Conference on High Energy Physics (ICHEP2018), 4-11 July, 2018, Seoul, Korea. Submitted to Proceedings of Science

Published
2018

41. Search for Tri-Nucleon Decay in the Majorana Demonstrator

Author

Alvis, S. I., Arnquist, I. J., Avignone III, F. T., Barabash, A. S., Barton, C. J., Bertrand, F. E., Bos, B., Brudanin, V., 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., Keeter, K. J., 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., Vasundhara, White, B. R., Wilkerson, J. F., Wiseman, C., Xu, W., Yakushev, E., Yu, C. -H., Yumatov, V., Zhitnikov, I., and Zhu, B. X.

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

The Majorana Demonstrator is an ultra low-background experiment searching for neutrinoless double-beta decay in $^{76}$Ge. The heavily shielded array of germanium detectors, placed nearly a mile underground at the Sanford Underground Research Facility in Lead, South Dakota, also allows searches for new exotic physics. We present the first limits for tri-nucleon decay-specific modes and invisible decay modes for Ge isotopes. We find a half-life limit of $4.9 \times 10^{25}$ yr for the decay $^{76}{\rm Ge(ppn)} \to {}^{73}{\rm Zn}\ e^+\pi^+$ and $4.7\times10^{25}$ yr for the decay $^{76}{\rm Ge(ppp)} \to ^{73}{\rm Cu}\ e^+\pi^+\pi^+$. The half-life limit for the invisible tri-proton decay mode of $^{76}$Ge was found to be $7.5\times10^{24}$ yr., Comment: Updated after suggested figure additions from referees

Published
2018
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42. Recent Results from the Majorana Demonstrator

Author

Gilliss, T, Alvis, S I, Arnquist, I J, Avignone III, F T, Barabash, A S, Barton, C J, Bertrand, F E, Bode, T, Brudanin, V, Busch, M, Buuck, M, Caldwell, T S, Chan, Y-D, Christofferson, C D, Chu, P -H, Cuesta, C, Detwiler, J A, Dunagan, C, Efremenko, Yu, Ejiri, H, Elliott, S R, Giovanetti, G K, Green, M P, Gruszko, J, Guinn, I S, Guiseppe, V E, Haufe, C R, Hehn, L, Henning, R, Hoppe, E W, Howe, M A, Keeter, K J, Kidd, M F, Konovalov, S I, Kouzes, R T, Lopez, A M, Martin, R D, Massarczyk, R, Meijer, S J, Mertens, S, Myslik, J, O'Shaughnessy, C, Othman, G, Pettus, W, Poon, A W P, Radford, D C, Rager, J, Reine, A L, Rielage, K, Robertson, R G H, Ruof, N W, Shanks, B, Shirchenko, M, Suriano, A M, Tedeschi, D, Varner, R L, Vasilyev, S, Vetter, K, Vorren, K, White, B R, Wilkerson, J F, Wiseman, C, Xu, W, Yakushev, E, Yu, C -H, Yumatov, V, Zhitnikov, I, and Zhu, B X

Subjects
Physics - Instrumentation and Detectors
Abstract

The MAJORANA Collaboration has completed construction and is now operating an array of high purity Ge detectors searching for neutrinoless double-beta decay ($0\nu\beta\beta$) in $^{76}$Ge. The array, known as the MAJORANA DEMONSTRATOR, is comprised of 44 kg of Ge detectors (30 kg enriched to 88% in $^{76}$Ge) installed in an ultra-low background compact shield at the Sanford Underground Research Facility in Lead, South Dakota. The primary goal of the DEMONSTRATOR is to establish a low-background design that can be scaled to a next-generation tonne-scale experiment. This work reports initial background levels in the $0\nu\beta\beta$ region of interest. Also presented are recent physics results leveraging P-type point-contact detectors with sub-keV energy thresholds to search for physics beyond the Standard Model; first results from searches for bosonic dark matter, solar axions, Pauli exclusion principle violation, and electron decay have been published. Finally, this work discusses the proposed tonne-scale $^{76}$Ge $0\nu\beta\beta$ LEGEND experiment., Comment: 6 pages, 1 figure, PANIC 2017: 21st Particles and Nuclei International Conference

Published
2018
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43. The Majorana Demonstrator Status and Preliminary Results

Author

Yu, C. -H., Alvis, S. I., Arnquist, I. J., Avignone III, F. T., Barabash, A. S., Barton, C. J., Bertrand, F. E., Bode, T., Brudanin, V., Busch, M., Buuck, M., Caldwell, T. S., Chan, Y. -D., Christofferson, C. D., Chu, P. -H., Cuesta, C., Detwiler, J. A., Dunagan, C., Efremenko, Yu, Ejiri, H., Elliott, S. R., Gilliss, T., Giovanetti, G. K., Green, M., Gruszko, J., Guinn, I. S., Guiseppe, V. E., Haufe, C. R., Hehn, L., Henning, R., Hoppe, E. W., Howe, M. A., Keeter, K. J., 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., Poon, A. W. P., Radford, D. C., Rager, J., Reine, A. L., Rielage, K., Ruff, N. W., Shanks, B., Shirchenko, M., Suriano, A. M., Tedeschi, D., Varner, R. L., Vasilyev, S., Vetter, K., Vorren, K., White, B. R., Wilkerson, J. F., Wiseman, C., Xu, W., Yakushev, E., Yumatov, V., Zhitnikov, I., and Zhu, B. Z.

Subjects
Nuclear Experiment, Physics - Instrumentation and Detectors
Abstract

The Majorana Collaboration is using an array of high-purity Ge detectors to search for neutrinoless double-beta decay in 76Ge. Searches for neutrinoless double-beta decay are understood to be the only viable experimental method for testing the Majorana nature of the neutrino. Observation of this decay would imply violation of lepton number, that neutrinos are Majorana in nature, and provide information on the neutrino mass. The Majorana Demonstrator comprises 44.1 kg of p-type point-contact Ge detectors (29.7 kg enriched in 76Ge) surrounded by a low-background shield system. The experiment achieved a high efficiency of converting raw Ge material to detectors and an unprecedented detector energy resolution of 2.5 keV FWHM at Q$_{\beta\beta}$. The Majorana collaboration began taking physics data in 2016. This paper summarizes key construction aspects of the Demonstrator and shows preliminary results from initial data., Comment: 5 pages, 2 figures. Proceeding for the "16th International Symposium on Capture Gamma-Ray Spectroscopy and Related Topics (CGS16)", 18-22 September 2017

Published
2018
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44. First Limit on the Direct Detection of Lightly Ionizing Particles for Electric Charge as Low as $e$/1000 with the \textsc{Majorana Demonstrator}

Author

Alvis, S. I., Arnquist, I. J., Avignone III, F. T., Barabash, A. S., Barton, C. J., Bertrand, F. E., Brudanin, V., Busch, M., Buuck, M., Caldwell, T. S., Chan, Y-D., Christofferson, C. D., Chu, P. -H., Cuesta, C., Detwiler, J. A., Dunagan, C., 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., Hehn, L., Henning, R., Hoppe, E. W., Howe, M. A., Konovalov, S. I., Kouzes, R. T., Lopez, A. M., Martin, R. D., Massarczyk, R., Meijer, S. J., Mertens, S., Myslik, J., O'Shaughnessy, C., Othman, G., Pettus, W., Poon, A. W. P., Radford, D. C., Rager, J., Reine, A. L., Rielage, K., Robertson, R. G. H., Ruof, N. W., Shanks, B., Shirchenko, M., Suriano, A. M., Tedeschi, D., Varner, R. L., Vasilyev, S., Vorren, K., White, B. R., Wilkerson, J. F., Wiseman, C., Xu, W., Yakushev, E., Yu, C. -H., Yumatov, V., Zhitnikov, I., and Zhu, B. X.

Subjects
High Energy Physics - Experiment, Astrophysics - Cosmology and Nongalactic Astrophysics, Physics - Instrumentation and Detectors
Abstract

The \textsc{Majorana Demonstrator} is an ultra low-background experiment searching for neutrinoless double-beta decay in $^{76}$Ge. The heavily shielded array of germanium detectors, placed nearly a mile underground at the Sanford Underground Research Facility in Lead, South Dakota, also allows searches for new exotic physics. Free, relativistic, lightly-ionizing particles with electrical charges less than $e$ are forbidden by the standard model but predicted by some of its extensions. If such particles exist, they might be detected in the \textsc{Majorana Demonstrator} by searching for multiple- detector events with individual-detector energy depositions down to 1 keV. This search is background free and no candidate events have been found in 285 days of data taking. New direct-detection limits are set for the flux of lightly ionizing particles for charges as low as $e$/1000., Comment: final version

Published
2018
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45. Low Background Materials and Fabrication Techniques for Cables and Connectors in the Majorana Demonstrator

Author

Busch, M., Abgrall, N., Alvis, S. I., Arnquist, I. J., Avignone III, F. T., Barabash, A. S., Barton, C. J., Bertrand, F. E., Bode, T., Bradley, A. W., Brudanin, V., Buuck, M., Caldwell, T. S., Chan, Y-D., Christofferson, C. D., Chu, P. -H., Cuesta, C., Detwiler, J. A., Dunagan, C., 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., Hehn, L., Henning, R., Hoppe, E. W., Howe, M. A., Keeter, K. J., Kidd, M. F., Konovalov, S. I., Kouzes, R. T., Lopez, A. M., Martin, R. D., Massarczyk, R., Meijer, S. J., Mertens, S., Myslik, J., O'Shaughnessy, C., Othman, G., Poon, A. W. P., Radford, D. C., Rager, J., Reine, A. L., Rielage, K., Robertson, R. G. H., Rouf, N. W., Shanks, B., Shirchenko, M., Suriano, A. M., Tedeschi, D., Trimble, J. E., Varner, R. L., Vasilyev, S., Vetter, K., Vorren, K., White, B. R., Wilkerson, J. F., Wiseman, C., Xu, W., Yakushev, E., Yu, C. -H., Yumatov, V., Zhitnikov, I., and Zhu, B. X.

Subjects
Physics - Instrumentation and Detectors
Abstract

The MAJORANA Collaboration is searching for the neutrinoless double-beta decay of the nucleus Ge-76. The MAJORANA DEMONSTRATOR is an array of germanium detectors deployed with the aim of implementing background reduction techniques suitable for a tonne scale Ge-76-based search (the LEGEND collaboration). In the DEMONSTRATOR, germanium detectors operate in an ultra-pure vacuum cryostat at 80 K. One special challenge of an ultra-pure environment is to develop reliable cables, connectors, and electronics that do not significantly contribute to the radioactive background of the experiment. This paper highlights the experimental requirements and how these requirements were met for the MAJORANA DEMONSTRATOR, including plans to upgrade the wiring for higher reliability in the summer of 2018. Also described are requirements for LEGEND R&D efforts underway to meet these additional requirements., Comment: Proceedings of LRT 2017

Published
2017
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46. Design improvements to cables and connectors in the Majorana Demonstrator

Author

Haufe, C. R., Reine, A. L., Abgrall, N., Alvis, S. I., Arnquist, I. J., Avignone III, F. T., Barabash, A. S., Barton, C. J., Bertrand, F. E., Bode, T., Bradley, A. W., Brudanin, V., Busch, M., Buuck, M., Caldwell, T. S., Chan, Y. -D., Christofferson, C. D., Chu, P. -H., Cuesta, C., Detwiler, J. A., Dunagan, C., Efremenko, Yu., Ejiri, H., Elliott, S. R., Gilliss, T., Giovanetti, G. K., Green, M. P., Gruszko, J., Guinn, I. S., Guiseppe, V. E., Hehn, L., Henning, R., Hoppe, E. W., Howe, M. A., Keeter, K. J., Kidd, M. F., Konovalov, S. I., Kouzes, R. T., Lopez, A. M., Martin, R. D., Massarczyk, R., Meijer, S. J., Mertens, S., Myslik, J., O'Shaughnessy, C., Othman, G., Pettus, W., Poon, A. W. P., Radford, D. C., Rager, J., Rielage, K., Robertson, R. G. H., Ruof, N. W., Shanks, B., Shirchenko, M., Suriano, A. M., Tedeschi, D., Trimble, J. E., Varner, R. L., Vasilyev, S., Vetter, K., Vorren, K., White, B. R., Wilkerson, J. F., Wiseman, C., Xu, W., Yakushev, E., Yu, C. -H., Yumatov, V., Zhitnikov, I., and Zhu, B. X.

Subjects
Physics - Instrumentation and Detectors
Abstract

The Majorana Demonstrator is an experiment constructed to search for neutrinoless double-beta decays in germanium-76 and to demonstrate the feasibility to deploy a ton-scale experiment in a phased and modular fashion. It consists of two modular arrays of natural and 76Ge-enriched germanium p-type point contact detectors totaling 44.1 kg, located at the 4850 level of the Sanford Underground Research Facility in Lead, South Dakota, USA. The Demonstrator uses custom high voltage cables to bias the detectors, as well as custom signal cables and connectors to read out the charge deposited at the point contact of each detector. These low-mass cables and connectors must meet stringent radiopurity requirements while being subjected to thermal and mechanical stress. A number of issues have been identified with the currently installed cables and connectors. An improved set of cables and connectors for the Majorana Demonstrator are being developed with the aim of increasing their overall reliability and connectivity. We will discuss some of the issues encountered with the current cables and connectors as well as our improved designs and their initial performance., Comment: 5 pages, 2 figures, TAUP 2017: XV International Conference on Topics in Astroparticle and Underground Physics

Published
2017

47. Initial Results from the Majorana Demonstrator

Author

Caldwell, T. S., Abgrall, N., Alvis, S. I., Arnquist, I. J., Avignone III, F. T., Barabash, A. S., Barton, C. J., Bertrand, F. E., Bode, T., Bos, B., Bradley, A. W., Brudanin, V., Busch, M., Buuck, M., Chan, Y-D., Christofferson, C. D., Chu, P. -H., Cuesta, C., Detwiler, J. A., Dunagan, C., 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., Hehn, L., Henning, R., Hoppe, E. W., Howe, M. A., Keeter, K. J., Kidd, M. F., Konovalov, S. I., Kouzes, R. T., Lopez, A. M., Martin, R. D., Massarczyk, R., Meijer, S. J., Mertens, S., Myslik, J., O'Shaughnessy, C., Othman, G., Pettus, W., Poon, A. W. P., Radford, D. C., Rager, J., Reine, A. L., Rielage, K., Robertson, R. G. H., Ruof, N. W., Shanks, B., Shirchenko, M., Suriano, A. M., Tedeschi, D., Trimble, J. E., Varner, R. L., Vasilyev, S., Vetter, K., Vorren, K., White, B. R., Wilkerson, J. F., Wiseman, C., Xu, W., Yakushev, E., Yu, C. -H., Yumatov, V., Zhitnikov, I., and Zhu, B. X.

Subjects
Physics - Instrumentation and Detectors, Nuclear Experiment
Abstract

The MAJORANA Collaboration has assembled an array of high purity Ge detectors to search for neutrinoless double-beta decay in $^{76}$Ge with the goal of establishing the required background and scalability of a Ge-based next-generation ton-scale experiment. The MAJORANA DEMONSTRATOR consists of 44 kg of high-purity Ge (HPGe) detectors (30 kg enriched in $^{76}$Ge) with a low-noise p-type point contact (PPC) geometry. The detectors are split between two modules which are contained in a single lead and high-purity copper shield at the Sanford Underground Research Facility in Lead, South Dakota. Following a commissioning run that started in June 2015, the full detector array has been acquiring data since August 2016. We will discuss the status of the MAJORANA DEMONSTRATOR and initial results from the first physics run; including current background estimates, exotic low-energy physics searches, projections on the physics reach of the DEMONSTRATOR, and implications for a ton-scale Ge-based neutrinoless double-beta decay search., Comment: Proceedings of TAUP 2017: XV International Conference on Topics in Astroparticle and Underground Physics (24-28 July 2017, Sudbury, ON, Canada)

Published
2017

48. Data quality assurance for the MAJORANA DEMONSTRATOR

Author

Myslik, J., Abgrall, N., Alvis, S. I., Arnquist, I. J., Avignone III, F. T., Barabash, A. S., Barton, C. J., Bertrand, F. E., Bode, T., Bradley, A. W., Brudanin, V., Busch, M., Buuck, M., Caldwell, T. S., Chan, Y-D., Christofferson, C. D., Chu, P-H., Cuesta, C., Detwiler, J. A., Dunagan, C., 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., Hehn, L., Henning, R., Hoppe, E. W., Howe, M. A., Keeter, K. J., Kidd, M. F., Konovalov, S. I., Kouzes, R. T., Lopez, A. M., Martin, R. D., Massarczyk, R., Meijer, S. J., Mertens, S., O'Shaughnessy, C., Othman, G., Pettus, W., Poon, A. W. P., Radford, D. C., Rager, J., Reine, A. L., Rielage, K., Robertson, R. G. H., Ruof, N. W., Shanks, B., Shirchenko, M., Suriano, A. M., Tedeschi, D., Trimble, J. E., Varner, R. L., Vasilyev, S., Vetter, K., Vorren, K., White, B. R., Wilkerson, J. F., Wiseman, C., Xu, W., Yakushev, E., Yu, C-H., Yumatov, V., Zhitnikov, I., and Zhu, B. X.

Subjects
Physics - Instrumentation and Detectors
Abstract

The MAJORANA DEMONSTRATOR is an experiment constructed to search for neutrinoless double-beta decays in germanium-76 and to demonstrate the feasibility to deploy a large-scale experiment in a phased and modular fashion. It consists of two modular arrays of natural and $^{76}$Ge-enriched germanium detectors totalling 44.1 kg, located at the 4850' level of the Sanford Underground Research Facility in Lead, South Dakota, USA. Any neutrinoless double-beta decay search requires a thorough understanding of the background and the signal energy spectra. The various techniques employed to ensure the integrity of the measured spectra are discussed. Data collection is monitored with a thorough set of checks, and subsequent careful analysis is performed to qualify the data for higher level physics analysis. Instrumental background events are tagged for removal, and problematic channels are removed from consideration as necessary., Comment: 5 pages, 2 figures, Proceedings of TAUP 2017 - XV International Conference on Topics in Astroparticle and Underground Physics (Sudbury ON, Canada, July 24-28, 2017)

Published
2017

49. Contamination Control and Assay Results for the Majorana Demonstrator Ultra Clean Components

Author

Christofferson, C. D., Abgrall, N., Alvis, S. I., Arnquist, I. J., Avignone III, F. T., Barabash, A. S., Barton, C. J., Bertrand, F. E., Bode, T., Bradley, A. W., Brudanin, V., Busch, M., Buuck, M., Caldwell, T. S., Chan, Y-D., Chu, P. -H., Cuesta, C., Detwiler, J. A., Dunagan, C., 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., Hehn, L., Henning, R., Hoppe, E. W., Howe, M. A., Keeter, K. J., Kidd, M. F., Konovalov, S. I., Kouzes, R. T., Lopez, A. M., Martin, R. D., Massarczyk, R., Meijer, S. J., Mertens, S., Myslik, J., O'Shaughnessy, C., Othman, G., Poon, A. W. P., Radford, D. C., Rager, J., Reine, A. L., Rielage, K., Robertson, R. G. H., Rouf, N. W., Shanks, B., Shirchenko, M., Suriano, A. M., Tedeschi, D., Trimble, J. E., Varner, R. L., Vasilyev, S., Vetter, K., Vorren, K., White, B. R., Wilkerson, J. F., Wiseman, C., Xu, W., Yakushev, E., Yu, C. -H., Yumatov, V., Zhitnikov, I., and Zhu, B. X.

Subjects
Physics - Instrumentation and Detectors, Nuclear Experiment
Abstract

The MAJORANA DEMONSTRATOR is a neutrinoless double beta decay experiment utilizing enriched Ge-76 detectors in 2 separate modules inside of a common solid shield at the Sanford Underground Research Facility. The DEMONSTRATOR has utilized world leading assay sensitivities to develop clean materials and processes for producing ultra-pure copper and plastic components. This experiment is now operating, and initial data provide new insights into the success of cleaning and processing. Post production copper assays after the completion of Module 1 showed an increase in U and Th contamination in finished parts compared to starting bulk material. A revised cleaning method and additional round of surface contamination studies prior to Module 2 construction have provided evidence that more rigorous process control can reduce surface contamination. This article describes the assay results and discuss further studies to take advantage of assay capabilities for the purpose of maintaining ultra clean fabrication and process design., Comment: Proceedings of Low Radioactivity Techniques (LRT May 2017, Seoul)

Published
2017
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50. Progress Toward A $2\nu\beta\beta$ Measurement For The Majorana Demonstrator

Author

Gilliss, T, Abgrall, N, Alvis, S I, Arnquist, I J, Avignone III, F T, Barabash, A S, Barton, C J, Bertrand, F E, Bode, T, Bradley, A W, Brudanin, V, Busch, M, Buuck, M, Caldwell, T S, Chan, Y-D, Christofferson, C D, Chu, P -H, Cuesta, C, Detwiler, J A, Dunagan, C, Efremenko, Yu, Ejiri, H, Elliott, S R, Giovanetti, G K, Green, M P, Gruszko, J, Guinn, I S, Guiseppe, V E, Haufe, C R, Hehn, L, Henning, R, Hoppe, E W, Howe, M A, Keeter, K J, Kidd, M F, Konovalov, S I, Kouzes, R T, Lopez, A M, Martin, R D, Massarczyk, R, Meijer, S J, Mertens, S, Myslik, J, O'Shaughnessy, C, Othman, G, Pettus, W, Poon, A W P, Radford, D C, Rager, J, Reine, A L, Rielage, K, Robertson, R G H, Ruof, N W, Shanks, B, Shirchenko, M, Suriano, A M, Tedeschi, D, Trimble, J E, Varner, R L, Vasilyev, S, Vetter, K, Vorren, K, White, B R, Wilkerson, J F, Wiseman, C, Xu, W, Yakushev, E, Yu, C -H, Yumatov, V, Zhitnikov, I, and Zhu, B X

Subjects
Physics - Instrumentation and Detectors
Abstract

The MAJORANA DEMONSTRATOR is a $^{76}$Ge-based neutrinoless double-beta decay ($0\nu\beta\beta$) experiment. Staged at the 4850 ft level of the Sanford Underground Research Facility, the DEMONSTRATOR operates an array of high-purity p-type point contact Ge detectors deployed within a graded passive shield and an active muon veto system. The present work concerns the two-neutrino double-beta decay mode ($2\nu\beta\beta$) of $^{76}$Ge. For Ge detectors, having superior energy resolution (0.1%), this mode poses negligible background to the $0\nu\beta\beta$ mode, even for a ton-scale experiment. However, the measurement of the $2\nu\beta\beta$ mode allows for careful systematics checks of active detector mass, enrichment fraction, and pulse shape discrimination cuts related to both the $0\nu\beta\beta$ and $2\nu\beta\beta$ decay modes. A precision measurement of the $2\nu\beta\beta$ shape also allows searches for spectral distortions, possibly indicative of new physics, including $0\nu\beta\beta\chi$. Work is underway to construct a full experimental background model enabling a Bayesian fit to the measured energy spectrum and extraction of a precise $2\nu\beta\beta$ spectrum and half-life., Comment: 5 pages, 2 figures, TAUP 2017: XV International Conference on Topics in Astroparticle and Underground Physics

Published
2017

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