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1. Direct determination of the $^{235}$U to $^{239}$Pu inverse beta decay yield ratio in the power reactor neutrino experiments

Author

Alekseev, I., Belov, V., Bystryakov, A., Danilov, M., Filosofov, D., Fomina, M., Gorovtsov, P., Iusko, Ye., Kazartsev, S., Khvatov, V., Kiselev, S., Kobyakin, A., Krapiva, A., Kuznetsov, A., Machikhiliyan, I., Mashin, N., Medvedev, D., Nesterov, V., Ponomarev, D., Rozova, I., Rumyantseva, N., Rusinov, V., Samigullin, E., Shevchik, Ye., Shirchenko, M., Shitov, Yu., Skrobova, N., Svirida, D., Tarkovsky, E., Yakushev, E., Zhitnikov, I., Yakovleva, A., and Zinatulina, D.

Subjects
Nuclear Experiment, High Energy Physics - Experiment
Abstract

The yields of the inverse beta decay events produced by antineutrinos from a certain nuclear reactor fuel component are used by many experiments to check various model predictions. Yet measurements of the absolute yields feature significant uncertainties coming, mainly, from the understanding of the antineutrino detection efficiency. This work presents a simple novel approach to directly determine the $^{235}$U to $^{239}$Pu inverse beta decay yield ratio using the fuel evolution analysis. This ratio can be used for a sensitive test of reactor models, while the proposed method, results in smaller systematic uncertainties., Comment: 5 pages, 2 figures

Published
2024

2. Long term remote reactor power and fuel composition monitoring using antineutrinos

Author

Alekseev, I., Belov, V., Bystryakov, A., Danilov, M., Filosofov, D., Fomina, M., Gorovtsov, P., Iusko, Ye., Kazartsev, S., Khvatov, V., Kiselev, S., Kobyakin, A., Krapiva, A., Kuznetsov, A., Machikhiliyan, I., Mashin, N., Medvedev, D., Nesterov, V., Ponomarev, D., Rozova, I., Rumyantseva, N., Rusinov, V., Salamatin, A., Samigullin, E., Shevchik, Ye., Shirchenko, M., Shitov, Yu., Skrobova, N., Svirida, D., Tarkovsky, E., Yakushev, E., Zhitnikov, I., Yakovleva, A., and Zinatulina, D.

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

Electron antineutrinos are emitted in the decay chains of the fission products inside a reactor core and could be used for remote monitoring of nuclear reactors. The DANSS detector is placed under the core of the 3.1 GW power reactor at the Kalinin Nuclear Power Plant (KNPP) and collects up to 5000 antineutrino events per day. DANSS measured changes of the reactor power by antineutrino counting rates over 7 years with 1.0% accuracy in one week periods. The systematic uncertainty of this measurement is less than 0.8%. It is comparable to the accuracy of conventional methods of the reactor power measurements while it is based on completely different approach. For the first time the 239Pu and 235U fission fractions were reconstructed using antineutrino inverse beta-decay spectrum which is a completely new technique. This method was applied to the data from three reactor fuel campaigns (approximately 1.5 year each). The reconstructed fission fractions in about one week measurements and the fission fractions provided by KNPP coincide within about 3% accuracy. This provides confidence in both completely different approaches of the fission fraction determination.

Published
2024

3. Searches for new physics below twice the electron mass with GERDA

Author

GERDA Collaboration, Agostini, M., Alexander, A., Araujo, G. R., Bakalyarov, A. M., Balata, M., Barabanov, I., Baudis, L., Bauer, C., Belogurov, S., Bettini, A., Bezrukov, L., Biancacci, V., Bossio, E., Bothe, V., Brugnera, R., Caldwell, A., Calgaro, S., Cattadori, C., Chernogorov, A., Chiu, P. -J., Comellato, T., D'Andrea, V., Demidova, E. V., Di Marco, N., Doroshkevich, E., Fomina, M., Gangapshev, A., Garfagnini, A., Gooch, C., Grabmayr, P., Gurentsov, V., Gusev, K., Hakenmüller, J., Hemmer, S., Hofmann, W., Huang, J., Hult, M., Inzhechik, L. V., Csáthy, J. Janicskó, Jochum, J., Junker, M., Kazalov, V., Kermaïdic, Y., Khushbakht, H., Kihm, T., Kilgus, K., Kirpichnikov, I. V., Klimenko, A., Knöpfle, K. T., Kochetov, O., Kornoukhov, V. N., Krause, P., Kuzminov, V. V., Laubenstein, M., Lindner, M., Lippi, I., Lubashevskiy, A., Lubsandorzhiev, B., Lutter, G., Macolino, C., Majorovits, B., Maneschg, W., Marshall, G., Misiaszek, M., Morella, M., Müller, Y., Nemchenok, I., Neuberger, M., Pandola, L., Pelczar, K., Pertoldi, L., Piseri, P., Pullia, A., Ransom, C., Rauscher, L., Redchuk, M., Riboldi, S., Rumyantseva, N., Sada, C., Sailer, S., Salamida, F., Schönert, S., Schreiner, J., Schütz, A-K., Schulz, O., Schwarz, M., Schwingenheuer, B., Selivanenko, O., Shevchik, E., Shirchenko, M., Shtembari, L., Simgen, H., Smolnikov, A., Stukov, D., Sullivan, S., Vasenko, A. A., Veresnikova, A., Vignoli, C., von Sturm, K., Wester, T., Wiesinger, C., Wojcik, M., Yanovich, E., Zatschler, B., Zhitnikov, I., Zhukov, S. V., Zinatulina, D., Zschocke, A., Zuber, K., and Zuzel, G.

Subjects
Nuclear Experiment, High Energy Physics - Experiment
Abstract

A search for full energy depositions from bosonic keV-scale dark matter candidates of masses between 65 keV and 1021 keV has been performed with data collected during Phase II of the GERmanium Detector Array (GERDA) experiment. Our analysis includes direct dark matter absorption as well as dark Compton scattering. With a total exposure of 105.5 kg yr, no evidence for a signal above the background has been observed. The resulting exclusion limits deduced with either Bayesian or Frequentist statistics are the most stringent direct constraints in the major part of the 140-1021 keV mass range. As an example, at a mass of 150 keV the dimensionless coupling of dark photons and axion-like particles to electrons has been constrained to $\alpha$'/$\alpha$ < 8.7x10$^{-24}$ and g$_{ae}$ < 3.3x10$^{-12}$ at 90% credible interval (CI), respectively. Additionally, a search for peak-like signals from beyond the Standard Model decays of nucleons and electrons is performed. We find for the inclusive decay of a single neutron in $^{76}$Ge a lower lifetime limit of $\tau_n$ > 1.5x10$^{24}$ yr and for a proton $\tau_p$ > 1.3x10$^{24}$ yr at 90% CI. For the electron decay e$^-\rightarrow\nu_e\gamma$ a lower limit of $\tau_e$ > 5.4x10$^{25}$ yr at 90% CI has been determined., Comment: 20 pages, 12 figures, 7 tables

Published
2024

4. Study of polysterene based scintillator ageing in the DANSS experiment

Author

DANSS Collaboration, Alekseev, I., Belov, V., Bystryakov, A., Danilov, M., Filosofov, D., Fomina, M., Gorovtsov, P., Iusko, Ye., Kazartsev, S., Kobyakin, A., Krapiva, A., Kuznetsov, A., Mashin, N., Machikhiliyan, I., Medvedev, D., Nesterov, V., Ponomarev, D., Rozova, I., Rumyantseva, N., Rusinov, V., Salamatin, A., Samigullin, E., Shevchik, Ye., Shirchenko, M., Shitov, Yu., Skrobova, N., Svirida, D., Tarkovsky, E., Yakovleva, A., Yakushev, E., Zhitnikov, I., and Zinatulina, D.

Subjects
Physics - Instrumentation and Detectors
Abstract

DANSS is a spectrometer of reactor antineutrino based on plastic scintillator. The sensitive volume of the detector is made of 2500 polystyrene based scintillator plates with wavelength shifting (WLS) fiber readout (strips). We present a study of the strips light yield during 6.5 years of DANSS continuous running. Overall ageing at the rate $0.55 \pm 0.05(syst.)$ % per year is observed that is considerably smaller than in other similar experiments. We also observe the WLS fiber attenuation length shortening at the rate $0.26 \pm 0.04(stat.)$ % per year., Comment: 9 pages, 7 figures, to be submitted to JINST

Published
2023
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5. An improved limit on the neutrinoless double-electron capture of $^{36}$Ar with GERDA

Author

GERDA Collaboration, Agostini, M., Alexander, A., Araujo, G. R., Bakalyarov, A. M., Balata, M., Barabanov, I., Baudis, L., Bauer, C., Belogurov, S., Bettini, A., Bezrukov, L., Biancacci, V., Bossio, E., Bothe, V., Brudanin, V., Brugnera, R., Caldwell, A., Cattadori, C., Chernogorov, A., Comellato, T., D'Andrea, V., Demidova, E. V., Di Marco, N., Doroshkevich, E., Fischer, F., Fomina, M., Gangapshev, A., Garfagnini, A., Gooch, C., Grabmayr, P., Gurentsov, V., Gusev, K., Hakenmüller, J., Hemmer, S., Hofmann, W., Huang, J., Hult, M., Inzhechik, L. V., Csáthy, J. Janicskó, Jochum, J., Junker, M., Kazalov, V., Kermaïdic, Y., Khushbakht, H., Kihm, T., Kilgus, K., Kirpichnikov, I. V., Klimenko, A., Kneißl, R., Knöpfle, K. T., Kochetov, O., Kornoukhov, V. N., Korošec, M., Krause, P., Kuzminov, V. V., Laubenstein, M., Lindner, M., Lippi, I., Lubashevskiy, A., Lubsandorzhiev, B., Lutter, G., Macolino, C., Majorovits, B., Maneschg, W., Manzanillas, L., Marshall, G., Misiaszek, M., Morella, M., Müller, Y., Nemchenok, I., Pandola, L., Pelczar, K., Pertoldi, L., Piseri, P., Pullia, A., Ransom, C., Rauscher, L., Redchuk, M., Riboldi, S., Rumyantseva, N., Sada, C., Salamida, F., Schönert, S., Schreiner, J., Schütt, M., Schütz, A-K., Schulz, O., Schwarz, M., Schwingenheuer, B., Selivanenko, O., Shevchik, E., Shirchenko, M., Shtembari, L., Simgen, H., Smolnikov, A., Stukov, D., Vasenko, A. A., Veresnikova, A., Vignoli, C., von Sturm, K., Wester, T., Wiesinger, C., Wojcik, M., Yanovich, E., Zatschler, B., Zhitnikov, I., Zhukov, S. V., Zinatulina, D., Zschocke, A., Zsigmond, A. J., Zuber, K., and Zuzel, G.

Subjects
Nuclear Experiment
Abstract

The GERmanium Detector Array (GERDA) experiment operated enriched high-purity germanium detectors in a liquid argon cryostat, which contains 0.33% of $^{36}$Ar, a candidate isotope for the two-neutrino double-electron capture (2$\nu$ECEC) and therefore for the neutrinoless double-electron capture (0$\nu$ECEC). If detected, this process would give evidence of lepton number violation and the Majorana nature of neutrinos. In the radiative 0$\nu$ECEC of $^{36}$Ar, a monochromatic photon is emitted with an energy of 429.88 keV, which may be detected by the GERDA germanium detectors. We searched for the $^{36}$Ar 0$\nu$ECEC with GERDA data, with a total live time of 4.34 yr (3.08 yr accumulated during GERDA Phase II and 1.26 yr during GERDA Phase I). No signal was found and a 90% C.L. lower limit on the half-life of this process was established T$_{1/2}$ > 1.5x10$^{22}$ yr, Comment: 10 pages, 5 figures, 1 table

Published
2023

6. Searches for new physics below twice the electron mass with GERDA

Author

Agostini, M., Alexander, A., Araujo, G., Bakalyarov, A. M., Balata, M., Barabanov, I., Baudis, L., Bauer, C., Belogurov, S., Bettini, A., Bezrukov, L., Biancacci, V., Bossio, E., Bothe, V., Brugnera, R., Caldwell, A., Calgaro, S., Cattadori, C., Chernogorov, A., Chiu, P.-J., Comellato, T., D’Andrea, V., Demidova, E. V., Marco, N. Di, Doroshkevich, E., Fomina, M., Gangapshev, A., Garfagnini, A., Gooch, C., Grabmayr, P., Gurentsov, V., Gusev, K., Hakenmüller, J., Hemmer, S., Hofmann, W., Huang, J., Hult, M., Inzhechik, L. V., Csáthy, J. Janicskó, Jochum, J., Junker, M., Kazalov, V., Kermaïdic, Y., Khushbakht, H., Kihm, T., Kilgus, K., Kirpichnikov, I. V., Klimenko, A., Knöpfle, K. T., Kochetov, O., Kornoukhov, V. N., Krause, P., Kuzminov, V. V., Laubenstein, M., Lindner, M., Lippi, I., Lubashevskiy, A., Lubsandorzhiev, B., Lutter, G., Macolino, C., Majorovits, B., Maneschg, W., Marshall, G., Misiaszek, M., Morella, M., Müller, Y., Nemchenok, I., Neuberger, M., Pandola, L., Pelczar, K., Pertoldi, L., Piseri, P., Pullia, A., Ransom, C., Rauscher, L., Redchuk, M., Riboldi, S., Rumyantseva, N., Sada, C., Sailer, S., Salamida, F., Schönert, S., Schreiner, J., Schütz, A-K., Schulz, O., Schwarz, M., Schwingenheuer, B., Selivanenko, O., Shevchik, E., Shirchenko, M., Shtembari, L., Simgen, H., Smolnikov, A., Stukov, D., Sullivan, S., Vasenko, A. A., Veresnikova, A., Vignoli, C., Sturm, K. von, Wester, T., Wiesinger, C., Wojcik, M., Yanovich, E., Zatschler, B., Zhitnikov, I., Zhukov, S. V., Zinatulina, D., Zschocke, A., Zuber, K., and Zuzel, G.

Published
2024
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7. Final Results of GERDA on the Two-Neutrino Double-$\beta$ Decay Half-Life of $^{76}$Ge

Author

GERDA collaboration, Agostini, M., Alexander, A., Araujo, G. R., Bakalyarov, A. M., Balata, M., Barabanov, I., Baudis, L., Bauer, C., Belogurov, S., Bettini, A., Bezrukov, L., Biancacci, V., Bossio, E., Bothe, V., Brugnera, R., Caldwell, A., Calgaro, S., Cattadori, C., Chernogorov, A., Chiu, P. -J., Comellato, T., D'Andrea, V., Demidova, E. V., Di Giacinto, A., Di Marco, N., Doroshkevich, E., Fischer, F., Fomina, M., Gangapshev, A., Garfagnini, A., Gooch, C., Grabmayr, P., Gurentsov, V., Gusev, K., Hackenmüller, S., Hemmer, S., Hofmann, W., Huang, J., Hult, M., Inzhechik, L. V., Csáthy, J. Janicskó, Jochum, J., Junker, M., Kazalov, V., Kermaïdic, Y., Khushbakht, H., Kihm, T., Kilgus, K., Kirpichnikov, I. V., Klimenko, A., Knöpfle, K. T., Kochetov, O., Kornoukhov, V. N., Krause, P., Kuzminov, V. V., Laubenstein, M., Lehnert, B., Lindner, M., Lippi, I., Lubashevskiy, A., Lubsandorzhiev, B., Lutter, G., Macolino, C., Majorovits, B., Maneschg, W., Manzanillas, L., Marshall, G., Miloradovic, M., Mingazheva, R., Misiaszek, M., Morella, M., Müller, Y., Nemchenok, I., Neuberger, M., Pandola, L., Pelczar, K., Pertoldi, L., Piseri, P., Pullia, A., Ransom, C., Rauscher, L., Redchuk, M., Riboldi, S., Rumyantseva, N., Sada, C., Sailer, S., Salamida, F., Schönert, S., Schreiner, J., Schütt, M., Schütz, A. -K., Schulz, O., Schwarz, M., Schwingenheuer, B., Selivanenko, O., Shevchik, E., Shirchenko, M., Shtembari, L., Simgen, H., Smolnikov, A., Stukov, D., Sullivan, S., Vasenko, A. A., Veresnikova, A., Vignoli, C., von Sturm, K., Wester, T., Wiesinger, C., Wojcik, M., Yanovich, E., Zatschler, B., Zhitnikov, I., Zhukov, S. V., Zinatulina, D., Zschocke, A., Zsigmond, A. J., Zuber, K., and Zuzel, G.

Subjects
Nuclear Experiment
Abstract

We present the measurement of the two-neutrino double-$\beta$ decay rate of $^{76}$Ge performed with the GERDA Phase II experiment. With a subset of the entire GERDA exposure, 11.8 kg$\cdot$yr, the half-life of the process has been determined: $T^{2\nu}_{1/2} = (2.022 \pm 0.018_{stat} \pm 0.038_{sys})\times10^{21}$ yr. This is the most precise determination of the $^{76}$Ge two-neutrino double-$\beta$ decay half-life and one of the most precise measurements of a double-$\beta$ decay process. The relevant nuclear matrix element can be extracted: $M^{2\nu}_{\text{eff}} = (0.101\pm0.001).$, Comment: 7 pages, 4 figures, 2 tables

Published
2023
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8. Search for tri-nucleon decays of $^{76}$Ge in GERDA

Author

GERDA collaboration, Agostini, M., Alexander, A., Araujo, G., Bakalyarov, A. M., Balata, M., Barabanov, I., Baudis, L., Bauer, C., Belogurov, S., Bettini, A., Bezrukov, L., Biancacci, V., Bossio, E., Bothe, V., Brugnera, R., Caldwell, A., Calgaro, S., Cattadori, C., Chernogorov, A., Chiu, P. -J., Comellato, T., D'Andrea, V., Demidova, E. V., Di Giacinto, A., Di Marco, N., Doroshkevich, E., Fischer, F., Fomina, M., Gangapshev, A., Garfagnini, A., Gooch, C., Grabmayr, P., Gurentsov, V., Gusev, K., Hakenmüller, J., Hemmer, S., Hofmann, W., Hult, M., Inzhechik, L. V., Csáthy, J. Janicskó, Jochum, J., Junker, M., Kazalov, V., Kermaïdic, Y., Khushbakht, H., Kihm, T., Kilgus, K., Kirpichnikov, I. V., Klimenko, A., Knöpfle, K. T., Kochetov, O., Kornoukhov, V. N., Krause, P., Kuzminov, V. V., Laubenstein, M., Lindner, M., Lippi, I., Lubashevskiy, A., Lubsandorzhiev, B., Lutter, G., Macolino, C., Majorovits, B., Maneschg, W., Manzanillas, L., Marshall, G., Misiaszek, M., Morella, M., Müller, Y., Nemchenok, I., Neuberger, M., Pandola, L., Pelczar, K., Pertoldi, L., Piseri, P., Pullia, A., Rauscher, L., Redchuk, M., Riboldi, S., Rumyantseva, N., Sada, C., Sailer, S., Salamida, F., Schönert, S., Schreiner, J., Schütt, M., Schütz, A-K., Schulz, O., Schwarz, M., Schwingenheuer, B., Selivanenko, O., Shevchik, E., Shirchenko, M., Shtembari, L., Simgen, H., Smolnikov, A., Stukov, D., Sullivan, S., Vasenko, A. A., Veresnikova, A., Vignoli, C., von Sturm, K., Wester, T., Wiesinger, C., Wojcik, M., Yanovich, E., Zatschler, B., Zhitnikov, I., Zhukov, S. V., Zinatulina, D., Zschocke, A., Zsigmond, A. J., Zuber, K., and Zuzel, G.

Subjects
Nuclear Experiment
Abstract

We search for tri-nucleon decays of $^{76}$Ge in the dataset from the GERmanium Detector Array (GERDA) experiment. Decays that populate excited levels of the daughter nucleus above the threshold for particle emission lead to disintegration and are not considered. The ppp-, ppn-, and pnn-decays lead to $^{73}$Cu, $^{73}$Zn, and $^{73}$Ga nuclei, respectively. These nuclei are unstable and eventually proceed by the beta decay of $^{73}$Ga to $^{73}$Ge (stable). We search for the $^{73}$Ga decay exploiting the fact that it dominantly populates the 66.7 keV $^{73m}$Ga state with half-life of 0.5 s. The nnn-decays of $^{76}$Ge that proceed via $^{73m}$Ge are also included in our analysis. We find no signal candidate and place a limit on the sum of the decay widths of the inclusive tri-nucleon decays that corresponds to a lower lifetime limit of 1.2x10$^{26}$ yr (90% credible interval). This result improves previous limits for tri-nucleon decays by one to three orders of magnitude., Comment: 8 pages, 9 figures, 3 tables

Published
2023
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9. Application of the Duperier method to the analysis of the cosmic muon flux dependence on the meteorological parameters, based on the DANSS detector data

Author

Alekseev, I., Belov, V., Danilov, M., Filosofov, D., Fomina, M., Kazartsev, S., Kobyakin, A., Kuznetsov, A., Machikhiliyan, I., Medvedev, D., Nesterov, V., Ponomarev, D., Rozova, I., Rumyantseva, N., Rusinov, V., Samigullin, E., Shevchik, Ye., Shirchenko, M., Shitov, Yu., Skrobova, N., Svirida, D., Tarkovsky, E., Yakovleva, A., Yakushev, E., Zhitnikov, I., and Zinatulina, D.

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

The detector DANSS is located under n industrial nuclear reactor at Kalininskaya Nuclear Power Plant. This location provides ~ 50 m.w.e. reduction of the cosmic muon flux in the vertical direction, which places the experiment in an intermediate position between ground and underground experiments in terms of shielding from the cosmic rays. The detector DANSS is located under an industrial nuclear reactor at Kalininskaya Nuclear Power Plant. This location provides ~50 m.w.e. reduction of the cosmic muon flux in the vertical direction, which places the experiment in an intermediate position between ground and underground experiments in terms of shielding from the cosmic rays. The detector's sensitive area consists of 2500 plastic scintillator counters, each 100x4x1 cm$^3$ in size, making in total a 1 m$^3$ volume, which is surrounded by a muon veto system and multiple layers of passive shielding. The main goal of the DANSS experiment is to study the antineutrino spectra at different distances from the source. For this purpose the detector is placed on a lifting platform, and the data is collected at three positions: 10.9 m, 11.9 m and 12.9 m from the center of the reactor core. The detector is capable of reconstructing muon tracks passing though the sensitive volume. In this work the barometric, height and temperature correlation coefficients are calculated in three areas of the zenith angle $\theta$ using the Duperier approach. These results are based on the muon data collected during four years., Comment: 7 pages, 3 figures, submitted to JETP letters (in Russian)

Published
2023
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10. Liquid argon light collection and veto modeling in GERDA Phase II

Author

GERDA collaboration, Agostini, M., Alexander, A., Araujo, G. R., Bakalyarov, A. M., Balata, M., Barabanov, I., Baudis, L., Bauer, C., Belogurov, S., Bettini, A., Bezrukov, L., Biancacci, V., Bossio, E., Bothe, V., Brugnera, R., Caldwell, A., Calgaro, S., Cattadori, C., Chernogorov, A., Chiu, P-J., Comellato, T., D'Andrea, V., Demidova, E. V., Di Giacinto, A., Di Marco, N., Doroshkevich, E., Fischer, F., Fomina, M., Gangapshev, A., Garfagnini, A., Gooch, C., Grabmayr, P., Gurentsov, V., Gusev, K., Hakenmüller, J., Hemmer, S., Hofmann, W., Hult, M., Inzhechik, L. V., Csáthy, J. Janicskó, Jochum, J., Junker, M., Kazalov, V., Kermaïdic, Y., Khushbakht, H., Kihm, T., Kilgus, K., Kirpichnikov, I. V., Klimenko, A., Knöpfle, K. T., Kochetov, O., Kornoukhov, V. N., Krause, P., Kuzminov, V. V., Laubenstein, M., Lehnert, B., Lindner, M., Lippi, I., Lubashevskiy, A., Lubsandorzhiev, B., Lutter, G., Macolino, C., Majorovits, B., Maneschg, W., Manzanillas, L., Marshall, G., Miloradovic, M., Mingazheva, R., Misiaszek, M., Morella, M., Müller, Y., Nemchenok, I., Neuberger, M., Pandola, L., Pelczar, K., Pertoldi, L., Piseri, P., Pullia, A., Rauscher, L., Redchuk, M., Riboldi, S., Rumyantseva, N., Sada, C., Sailer, S., Salamida, F., Schönert, S., Schreiner, J., Schütt, M., Schütz, A-K., Schulz, O., Schwarz, M., Schwingenheuer, B., Selivanenko, O., Shevchik, E., Shirchenko, M., Shtembari, L., Simgen, H., Smolnikov, A., Stukov, D., Sullivan, S., Vasenko, A. A., Veresnikova, A., Vignoli, C., von Sturm, K., Wegmann, A., Wester, T., Wiesinger, C., Wojcik, M., Yanovich, E., Zatschler, B., Zhitnikov, I., Zhukov, S. V., Zinatulina, D., Zschocke, A., Zsigmond, A. J., Zuber, K., and Zuzel, G.

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

The ability to detect liquid argon scintillation light from within a densely packed high-purity germanium detector array allowed the GERDA experiment to reach an exceptionally low background rate in the search for neutrinoless double beta decay of $^{76}$Ge. Proper modeling of the light propagation throughout the experimental setup, from any origin in the liquid argon volume to its eventual detection by the novel light read-out system, provides insight into the rejection capability and is a necessary ingredient to obtain robust background predictions. In this paper, we present a model of the GERDA liquid argon veto, as obtained by Monte Carlo simulations and constrained by calibration data, and highlight its application for background decomposition.

Published
2022
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11. The Majorana Demonstrator Status and Preliminary Results

Author

Yu C.-H., Alvis S.I., Arnquist I.J., Avignone 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., 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., Yumatov V., Zhitnikov I., and Zhu B.Z.

Subjects
Physics, QC1-999
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 Qββ. 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.

Published
2018
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12. Search for exotic physics in double-$\beta$ decays with GERDA Phase II

Author

The GERDA collaboration, Agostini, M., Alexander, A., Araujo, G., Bakalyarov, A. M., Balata, M., Barabanov, I., Baudis, L., Bauer, C., Belogurov, S., Bettini, A., Bezrukov, L., Biancacci, V., Bossio, E., Bothe, V., Brugnera, R., Caldwell, A., Cattadori, C., Chernogorov, A., Comellato, T., D'Andrea, V., Demidova, E. V., Di Giacinto, A., Di Marco, N., Doroshkevich, E., Fischer, F., Fomina, M., Gangapshev, A., Garfagnini, A., Gooch, C., Grabmayr, P., Gurentsov, V., Gusev, K., Hakenmüller, J., Hemmer, S., Hofmann, W., Huang, J., Hult, M., Inzhechik, L. V., Csáthy, J. Janicskó, Jochum, J., Junker, M., Kazalov, V., Kermaïdic, Y., Khushbakht, H., Kihm, T., Kilgus, K., Kirpichnikov, I. V., Klimenko, A., Knöpfle, K. T., Kochetov, O., Kornoukhov, V. N., Krause, P., Kuzminov, V. V., Laubenstein, M., Lindner, M., Lippi, I., Lubashevskiy, A., Lubsandorzhiev, B., Lutter, G., Macolino, C., Majorovits, B., Maneschg, W., Manzanillas, L., Marshall, G., Miloradovic, M., Mingazheva, R., Misiaszek, M., Morella, M., Müller, Y., Nemchenok, I., Pandola, L., Pelczar, K., Pertoldi, L., Piseri, P., Pullia, A., Ransom, C., Rauscher, L., Redchuk, M., Riboldi, S., Rumyantseva, N., Sada, C., Sailer, S., Salamida, F., Schönert, S., Schreiner, J., Schütt, M., Schütz, A. -K., Schulz, O., Schwarz, M., Schwingenheuer, B., Selivanenko, O., Shevchik, E., Shirchenko, M., Shtembari, L., Simgen, H., Smolnikov, A., Stukov, D., Vasenko, A. A., Veresnikova, A., Vignoli, C., von Sturm, K., Wester, T., Wiesinger, C., Wojcik, M., Yanovich, E., Zatschler, B., Zhitnikov, I., Zhukov, S. V., Zinatulina, D., Zschocke, A., Zsigmond, A. J., Zuber, K., and Zuzel, G.

Subjects
Nuclear Experiment, High Energy Physics - Experiment
Abstract

A search for Beyond the Standard Model double-$\beta$ decay modes of $^{76}$Ge has been performed with data collected during the Phase II of the GERmanium Detector Array (GERDA) experiment, located at Laboratori Nazionali del Gran Sasso of INFN (Italy). Improved limits on the decays involving Majorons have been obtained, compared to previous experiments with $^{76}$Ge, with half-life values on the order of 10$^{23}$ yr. For the first time with $^{76}$Ge, limits on Lorentz invariance violation effects in double-$\beta$ decay have been obtained. The isotropic coefficient $\mathring{a}_\text{of}^{(3)}$, which embeds Lorentz violation in double-$\beta$ decay, has been constrained at the order of $10^{-6}$ GeV. We also set the first experimental limits on the search for light exotic fermions in double-$\beta$ decay, including sterile neutrinos.

Published
2022

13. First results of the nuGeN experiment on coherent elastic neutrino-nucleus scattering

Author

Alekseev, I., Balej, K., Belov, V., Evseev, S., Filosofov, D., Fomina, M., Hons, Z., Karaivanov, D., Kazartsev, S., Khushvaktov, J., Kuznetsov, A., Lubashevskiy, A., Medvedev, D., Ponomarev, D., Rakhimov, A., Shakhov, K., Shevchik, E., Shirchenko, M., Smolek, K., Rozov, S., Rozova, I., Vasilyev, S., Yakushev, E., and Zhitnikov, I.

Subjects
Nuclear Experiment, High Energy Physics - Experiment
Abstract

The nuGeN experiment is aimed to investigate neutrino properties using antineutrinos from the reactor of the Kalinin Nuclear Power Plant. The experimental setup is located at about 11 meters from the center of the 3.1 GWth reactor core. Scattering of the antineutrinos from the reactor is detected with low energy threshold high purity germanium detector. Passive and active shieldings are used to suppress all kinds of backgrounds coming from surrounding materials and cosmic radiation. The description of the experimental setup together with the first results is presented. The data taken in regimes with reactor ON (94.50 days) and reactor OFF (47.09 days) have been compared. No significant difference between spectra of two data sets is observed, i.e. no positive signals for coherent elastic neutrino-nucleus scattering are detected. Under Standard Model assumptions about coherent neutrino scattering an upper limit on a quenching parameter k < 0.26 (90 \% C.L.) in germanium has been set.

Published
2022
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14. Pulse shape analysis in GERDA Phase II

Author

The GERDA collaboration, Agostini, M., Araujo, G., Bakalyarov, A. M., Balata, M., Barabanov, I., Baudis, L., Bauer, C., Bellotti, E., Belogurov, S., Bettini, A., Bezrukov, L., Biancacci, V., Bossio, E., Bothe, V., Brudanin, V., Brugnera, R., Caldwell, A., Cattadori, C., Chernogorov, A., Comellato, T., D'Andrea, V., Demidova, E. V., Di Marco, N., Doroshkevich, E., Fischer, F., Fomina, M., Gangapshev, A., Garfagnini, A., Gooch, C., Grabmayr, P., Gurentsov, V., Gusev, K., Hakenmüller, J., Hemmer, S., Hiller, R., Hofmann, W., Huang, J., Hult, M., Inzhechik, L. V., Csáthy, J. Janicskó, Jochum, J., Junker, M., Kazalov, V., Kermaïdic, Y., Khushbakht, H., Kihm, T., Kilgus, K., Kirsch, A., Kirpichnikov, I. V., Klimenko, A., Knöpfle, K. T., Kochetov, O., Kornoukhov, V. N., Krause, P., Kuzminov, V. V., Laubenstein, M., Lazzaro, A., Lindner, M., Lippi, I., Lubashevskiy, A., Lubsandorzhiev, B., Lutter, G., Macolino, C., Majorovits, B., Maneschg, W., Manzanillas, L., Miloradovic, M., Mingazheva, R., Misiaszek, M., Müller, Y., Nemchenok, I., Panas, K., Pandola, L., Pelczar, K., Pertoldi, L., Piseri, P., Pullia, A., Ransom, C., Rauscher, L., Redchuk, M., Riboldi, S., Rumyantseva, N., Sada, C., Salamida, F., Schönert, S., Schreiner, J., Schütt, M., Schütz, A. -K., Schulz, O., Schwarz, M., Schwingenheuer, B., Selivanenko, O., Shevchik, E., Shirchenko, M., Shtembari, L., Simgen, H., Smolnikov, A., Stukov, D., Vasenko, A. A., Veresnikova, A., Vignoli, C., von Sturm, K., Wagner, V., Wester, T., Wiesinger, C., Wojcik, M., Yanovich, E., Zatschler, B., Zhitnikov, I., Zhukov, S. V., Zinatulina, D., Zschocke, A., Zsigmond, A. J., Zuber, K., and Zuzel, G.

Subjects
Physics - Instrumentation and Detectors, Nuclear Experiment
Abstract

The GERmanium Detector Array (GERDA) collaboration searched for neutrinoless double-$\beta$ decay in $^{76}$Ge using isotopically enriched high purity germanium detectors at the Laboratori Nazionali del Gran Sasso of INFN. After Phase I (2011-2013), the experiment benefited from several upgrades, including an additional active veto based on LAr instrumentation and a significant increase of mass by point-contact germanium detectors that improved the half-life sensitivity of Phase II (2015-2019) by an order of magnitude. At the core of the background mitigation strategy, the analysis of the time profile of individual pulses provides a powerful topological discrimination of signal-like and background-like events. Data from regular $^{228}$Th calibrations and physics data were both considered in the evaluation of the pulse shape discrimination performance. In this work, we describe the various methods applied to the data collected in GERDA Phase II corresponding to an exposure of 103.7 kg$\cdot$yr. These methods suppress the background by a factor of about 5 in the region of interest around Q$_{\beta\beta}$ = 2039 keV, while preserving (81$\pm$3)% of the signal. In addition, an exhaustive list of parameters is provided which were used in the final data analysis.

Published
2022
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15. Optimized scintillation strip design for the DANSS upgrade

Author

DANSS Collaboration, Alekseev, I., Belov, V., Bystryakov, A., Danilov, M., Ershova, A., Filosofov, D., Fomina, M., Kazartsev, S., Kobyakin, A., Kozlenko, N., Kuznetsov, A., Machikhiliyan, I., Mamedov, F., Medvedev, D., Nesterov, V., Novinsky, D., Perminov, K., Rozova, I., Rumyantseva, N., Rusinov, V., Salamatin, A., Samigullin, E., Shevchik, Ye., Shirchenko, M., Shitov, Yu., Skrobova, N., Starostin, A., Stekl, I., Svirida, D., Tarkovsky, E., Yakovleva, A., Yakushev, E., Zhitnikov, I., and Zinatulina, D.

Subjects
Physics - Instrumentation and Detectors
Abstract

DANSS is a one cubic meter plastic scintillator detector with a primary goal of the sterile neutrino searches at a commercial nuclear reactor. Due to its highly advantageous location, fine segmentation and ability to change the distance to the neutrino production origin DANSS is ahead of many similar experiments around the world in terms of the counting rate, signal to background ratio and sterile neutrino exclusion regions. Yet a moderate energy resolution of the detector prevents the further progress in the physics program. The main challenge of the planned upgrade is to achieve the energy resolution of 12% at 1 MeV. The new design of the main sensitive element - the plastic scintillation strip - is the most important step forward. The strip prototypes were manufactured and tested at the pion beam of the PNPI synchrocyclotron. More than twice higher light output together with fairly flat detector response uniformity, longitudinal timing information and other optimizations will surely help to reach the upgrade goal. The paper discusses the drawbacks of the current strip version, outlines the new features of the proposed upgrade, describes the beam test procedure and presents the test results reflecting the advantages of the new strip design in comparison with the currently used version., Comment: 12 pages, 8 figures, corresponding author D. Svirida, accepted for publication in JINST, the accepted version, minor revisions

Published
2021
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16. Observation of the temperature and barometric effects on the cosmic muon flux by the DANSS detector

Author

DANSS Collaboration, Alekseev, I., Belov, V., Brudanin, V., Bystryakov, A., Danilov, M., Egorov, V., Filosofov, D., Fomina, M., Kazartsev, S., Kobyakin, A., Kuznetsov, A., Machikhiliyan, I., Medvedev, D., Nesterov, V., Rozova, I., Rumyantseva, N., Rusinov, V., Samigullin, E., Shevchik, Ye., Shirchenko, M., Shitov, Yu., Skrobova, N., Starostin, A., Svirida, D., Tarkovsky, E., Yakushev, E., Zhitnikov, I., and Zinatulina, D.

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

The DANSS detector is located directly below a commercial reactor core at the Kalinin Nuclear Power Plant. Such a position provides an overburden about 50 m.w.e. in vertical direction. In terms of the cosmic rays it occupies an intermediate position between surface and underground detectors. The sensitive volume of the detector is a cubic meter of plastic scintillator with fine segmentation and combined PMT and SiPM readout, surrounded by multilayer passive and active shielding. The detector can reconstruct muon tracks passing through its sensitive volume. The main physics goal of the DANSS experiment implies the antineutrino spectra measurements at various distances from the source. This is achieved by means of a lifting platform so that the data is taken in three positions - 10.9, 11.9 and 12.9 meters from the reactor core. The muon data were collected for nearly four calendar years. The overburden parameters $\langle E_{thr}\cos\theta \rangle$ and $\langle E_{thr} \rangle$, as well as the temperature and barometric correlation coefficients are evaluated separately for the three detector positions and, in each position, in three ranges of the zenith angle - for nearly vertical muons with $\cos\theta>0.9$, for nearly horizontal muons with $\cos\theta<0.36$, and for the whole upper hemisphere., Comment: 12 pages, 13 figures, submitted to the European Physical Journal C (EPJ C), the accepted revision

Published
2021

17. NaI(Tl+Li) scintillator as multirange energies neutron detector

Author

Ponomarev, D., Filosofov, D., Khushvaktov, J., Lubashevskiy, A., Rozova, I., Rozov, S., Shakhov, K., Shitov, Yu., Timkin, V., Yakushev, E., and Zhitnikov, I.

Subjects
Physics - Instrumentation and Detectors
Abstract

Novel NaIL detector (5x6 inch) was investigated for aims of neutron detection in wide energy range. It has been found that the detector together with its known ability to detect the {\gamma}- radiation is also allows to distinguish neutron signals in three quasi-independent ways. It sensitive to neutron fluxes on a level down to $10^{-3}$ $cm^{-2}$ $s^{-1}$. In the work intrinsic {\alpha}- background and neutron detection efficiency for the NaIL detector were obtained. Experimental data was compared with results of Geant4 Monte Carlo (MC).

Published
2021
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18. 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

19. Effect of Meteorological Parameters on the Cosmic Muon Flux Studied Using the Effective Generation Level Method with the DANSS Detector Data

Author

Alekseev, I. G., Belov, V. V., Danilov, M. V., Zhitnikov, I. V., Zinatulina, D. R., Kazartsev, S. V., Kobyakin, A. S., Kuznetsov, A. S., Machikhiliyan, I. V., Medvedev, D. V., Nesterov, V. M., Ponomarev, D. V., Rozova, I. E., Rumyantseva, N. S., Rusinov, V. Yu., Samigullin, E. I., Svirida, D. N., Skrobova, N. A., Tarkovsky, E. I., Filosofov, D. V., Fomina, M. V., Shevchik, E. A., Shirchenko, M. V., Shitov, Yu. A., Yakovleva, A. E., and Yakushev, E. A.

Published
2023
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20. Characterization of inverted coaxial $^{76}$Ge detectors in GERDA for future double-$\beta$ decay experiments

Author

GERDA collaboration, Agostini, M., Araujo, G. R., Bakalyarov, A. M., Balata, M., Barabanov, I., Baudis, L., Bauer, C., Bellotti, E., Belogurov, S., Bettini, A., Bezrukov, L., Biancacci, V., Bossio, E., Bothe, V., Brudanin, V., Brugnera, R., Caldwell, A., Cattadori, C., Chernogorov, A., Comellato, T., D'Andrea, V., Demidova, E. V., Di Marco, N., Doroshkevich, E., Fischer, F., Fomina, M., Gangapshev, A., Garfagnini, A., Gooch, C., Grabmayr, P., Gurentsov, V., Gusev, K., Hakenmüller, J., Hemmer, S., Hofmann, W., Huang, J., Hult, M., Inzhechik, L. V., Csáthy, J. Janicskó, Jochum, J., Junker, M., Kazalov, V., Kermaïdic, Y., Khushbakht, H., Kihm, T., Kirpichnikov, I. V., Klimenko, A., Kneißl, R., Knöpfle, K. T., Kochetov, O., Kornoukhov, V. N., Krause, P., Kuzminov, V. V., Laubenstein, M., Lindner, M., Lippi, I., Lubashevskiy, A., Lubsandorzhiev, B., Lutter, G., Macolino, C., Majorovits, B., Maneschg, W., Manzanillas, L., Miloradovic, M., Mingazheva, R., Misiaszek, M., Moseev, P., Müller, Y., Nemchenok, I., Pandola, L., Pelczar, K., Pertoldi, L., Piseri, P., Pullia, A., Ransom, C., Rauscher, L., Riboldi, S., Rumyantseva, N., Sada, C., Salamida, F., Schönert, S., Schreiner, J., Schütt, M., Schütz, A. -K., Schulz, O., Schwarz, M., Schwingenheuer, B., Selivanenko, O., Shevchik, E., Shirchenko, M., Shtembari, L., Simgen, H., Smolnikov, A., Stukov, D., Vasenko, A. A., Veresnikova, A., Vignoli, C., von Sturm, K., Wester, T., Wiesinger, C., Wojcik, M., Yanovich, E., Zatschler, B., Zhitnikov, I., Zhukov, S. V., Zinatulina, D., Zschocke, A., Zsigmond, A. J., Zuber, K., and Zuzel, G.

Subjects
Physics - Instrumentation and Detectors, Nuclear Experiment
Abstract

Neutrinoless double-$\beta$ decay of $^{76}$Ge is searched for with germanium detectors where source and detector of the decay are identical. For the success of future experiments it is important to increase the mass of the detectors. We report here on the characterization and testing of five prototype detectors manufactured in inverted coaxial (IC) geometry from material enriched to 88% in $^{76}$Ge. IC detectors combine the large mass of the traditional semi-coaxial Ge detectors with the superior resolution and pulse shape discrimination power of point contact detectors which exhibited so far much lower mass. Their performance has been found to be satisfactory both when operated in vacuum cryostat and bare in liquid argon within the GERDA setup. The measured resolutions at the Q-value for double-$\beta$ decay of $^{76}$Ge (Q$_{\beta\beta}$ = 2039 keV) are about 2.1 keV full width at half maximum in vacuum cryostat. After 18 months of operation within the ultra-low background environment of the GERmanium Detector Array (GERDA) experiment and an accumulated exposure of 8.5 kg$\cdot$yr, the background index after analysis cuts is measured to be $4.9^{+7.3}_{-3.4}\times 10^{-4}$ counts /(keV$\cdot$kg$\cdot$yr) around Q$_{\beta\beta}$. This work confirms the feasibility of IC detectors for the next-generation experiment LEGEND., Comment: 13 pages, 12 figures, submitted to EPJC

Published
2021
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21. Calibration of the GERDA experiment

Author

GERDA collaboration, Agostini, M., Araujo, G. R., Bakalyarov, A. M., Balata, M., Barabanov, I., Baudis, L., Bauer, C., Bellotti, E., Belogurov, S., Bettini, A., Bezrukov, L., Biancacci, V., Bossio, E., Bothe, V., Brudanin, V., Brugnera, R., Caldwell, A., Cattadori, C., Chernogorov, A., Comellato, T., D'Andrea, V., Demidova, E. V., Di Marco, N., Doroshkevich, E., Fischer, F., Fomina, M., Gangapshev, A., Garfagnini, A., Gooch, C., Grabmayr, P., Gurentsov, V., Gusev, K., Hakenmüller, J., Hemmer, S., Hiller, R., Hofmann, W., Huang, J., Hult, M., Inzhechik, L. V., Csáthy, J. Janicskó, Jochum, J., Junker, M., Kazalov, V., Kermaïdic, Y., Khushbakht, H., Kihm, T., Kirpichnikov, I. V., Klimenko, A., Kneißl, R., Knöpfle, K. T., Kochetov, O., Kornoukhov, V. N., Krause, P., Kuzminov, V. V., Laubenstein, M., Lindner, M., Lippi, I., Lubashevskiy, A., Lubsandorzhiev, B., Lutter, G., Macolino, C., Majorovits, B., Maneschg, W., Manzanillas, L., Miloradovic, M., Mingazheva, R., Misiaszek, M., Moseev, P., Müller, Y., Nemchenok, I., Pandola, L., Pelczar, K., Pertoldi, L., Piseri, P., Pullia, A., Ransom, C., Rauscher, L., Riboldi, S., Rumyantseva, N., Sada, C., Salamida, F., Schönert, S., Schreiner, J., Schütt, M., Schütz, A. -K., Schulz, O., Schwarz, M., Schwingenheuer, B., Selivanenko, O., Shevchik, E., Shirchenko, M., Shtembari, L., Simgen, H., Smolnikov, A., Stukov, D., Vasenko, A. A., Veresnikova, A., Vignoli, C., von Sturm, K., Wester, T., Wiesinger, C., Wojcik, M., Yanovich, E., Zatschler, B., Zhitnikov, I., Zhukov, S. V., Zinatulina, D., Zschocke, A., Zsigmond, A. J., Zuber, K., and Zuzel, G.

Subjects
Physics - Instrumentation and Detectors, Nuclear Experiment
Abstract

The GERmanium Detector Array (GERDA) collaboration searched for neutrinoless double-$\beta$ decay in $^{76}$Ge with an array of about 40 high-purity isotopically-enriched germanium detectors. The experimental signature of the decay is a monoenergetic signal at Q$_{\beta\beta}$ = 2039.061(7)keV in the measured summed energy spectrum of the two emitted electrons. Both the energy reconstruction and resolution of the germanium detectors are crucial to separate a potential signal from various backgrounds, such as neutrino-accompanied double-$\beta$ decays allowed by the Standard Model. The energy resolution and stability were determined and monitored as a function of time using data from regular $^{228}$Th calibrations. In this work, we describe the calibration process and associated data analysis of the full GERDA dataset, tailored to preserve the excellent resolution of the individual germanium detectors when combining data over several years., Comment: 12 pages, 7 figures

Published
2021
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22. Final Results of GERDA on the Search for Neutrinoless Double-$\beta$ Decay

Author

GERDA collaboration, Agostini, M., Araujo, G. R., Bakalyarov, A. M., Balata, M., Barabanov, I., Baudis, L., Bauer, C., Bellotti, E., Belogurov, S., Bettini, A., Bezrukov, L., Biancacci, V., Borowicz, D., Bossio, E., Bothe, V., Brudanin, V., Brugnera, R., Caldwell, A., Cattadori, C., Chernogorov, A., Comellato, T., D'Andrea, V., Demidova, E. V., Di Marco, N., Doroshkevich, E., Fischer, F., Fomina, M., Gangapshev, A., Garfagnini, A., Gooch, C., Grabmayr, P., Gurentsov, V., Gusev, K., Hakenmüller, J., Hemmer, S., Hiller, R., Hofmann, W., Huang, J., Hult, M., Inzhechik, L. V., Csáthy, J. Janicskó, Jochum, J., Junker, M., Kazalov, V., Kermaïdic, Y., Khushbakht, H., Kihm, T., Kirpichnikov, I. V., Klimenko, A., Kneißl, R., Knöpfle, K. T., Kochetov, O., Kornoukhov, V. N., Krause, P., Kuzminov, V. V., Laubenstein, M., Lazzaro, A., Lindner, M., Lippi, I., Lubashevskiy, A., Lubsandorzhiev, B., Lutter, G., Macolino, C., Majorovits, B., Maneschg, W., Manzanillas, L., Miloradovic, M., Mingazheva, R., Misiaszek, M., Moseev, P., Müller, Y., Nemchenok, I., Panas, K., Pandola, L., Pelczar, K., Pertoldi, L., Piseri, P., Pullia, A., Ransom, C., Rauscher, L., Riboldi, S., Rumyantseva, N., Sada, C., Salamida, F., Schönert, S., Schreiner, J., Schütt, M., Schütz, A. -K., Schulz, O., Schwarz, M., Schwingenheuer, B., Selivanenko, O., Shevchik, E., Shirchenko, M., Shtembari, L., Simgen, H., Smolnikov, A., Stukov, D., Vasenko, A. A., Veresnikova, A., Vignoli, C., von Sturm, K., Wester, T., Wiesinger, C., Wojcik, M., Yanovich, E., Zatschler, B., Zhitnikov, I., Zhukov, S. V., Zinatulina, D., Zschocke, A., Zsigmond, A. J., Zuber, K., and Zuzel, G.

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

The GERmanium Detector Array (GERDA) experiment searched for the lepton-number-violating neutrinoless double-$\beta$ ($0\nu\beta\beta$) decay of $^{76}$Ge, whose discovery would have far-reaching implications in cosmology and particle physics. By operating bare germanium diodes, enriched in $^{76}$Ge, in an active liquid argon shield, GERDA achieved an unprecedently low background index of $5.2\times10^{-4}$ counts/(keV$\cdot$kg$\cdot$yr) in the signal region and met the design goal to collect an exposure of 100 kg$\cdot$yr in a background-free regime. When combined with the result of Phase I, no signal is observed after 127.2 kg$\cdot$yr of total exposure. A limit on the half-life of $0\nu\beta\beta$ decay in $^{76}$Ge is set at $T_{1/2}>1.8\times10^{26}$ yr at 90% C.L., which coincides with the sensitivity assuming no signal., Comment: 7 pages, 3 figures, submitted to Physical Review Letters

Published
2020
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23. The first search for bosonic super-WIMPs with masses up to 1 MeV/c$^2$ with GERDA

Author

GERDA collaboration, Agostini, M., Bakalyarov, A. M., Balata, M., Barabanov, I., Baudis, L., Bauer, C., Bellotti, E., Belogurov, S., Bettini, A., Bezrukov, L., Borowicz, D., Bossio, E., Bothe, V., Brudanin, V., Brugnera, R., Caldwell, A., Cattadori, C., Chernogorov, A., Comellato, T., D'Andrea, V., Demidova, E. V., Di Marco, N., Doroshkevich, E., Egorov, V., Fischer, F., Fomina, M., Gangapshev, A., Garfagnini, A., Gooch, C., Grabmayr, P., Gurentsov, V., Gusev, K., Hakenmüller, J., Hemmer, S., Hiller, R., Hofmann, W., Hult, M., Inzhechik, L. V., Csáthy, J. Janicskó, Jochum, J., Junker, M., Kazalov, V., Kermaïdic, Y., Khushbakht, H., Kihm, T., Kirpichnikov, I. V., Klimenko, A., Kneißl, R., Knöpfle, K. T., Kochetov, O., Kornoukhov, V. N., Krause, P., Kuzminov, V. V., Laubenstein, M., Lazzaro, A., Lindner, M., Lippi, I., Lubashevskiy, A., Lubsandorzhiev, B., Lutter, G., Macolino, C., Majorovits, B., Maneschg, W., Miloradovic, M., Mingazheva, R., Misiaszek, M., Moseev, P., Nemchenok, I., Panas, K., Pandola, L., Pelczar, K., Pertoldi, L., Piseri, P., Pullia, A., Ransom, C., Rauscher, L., Riboldi, S., Rumyantseva, N., Sada, C., Salamida, F., Schönert, S., Schreiner, J., Schütt, M., Schütz, A-K., Schulz, O., Schwarz, M., Schwingenheuer, B., Selivanenko, O., Shevchik, E., Shirchenko, M., Simgen, H., Smolnikov, A., Stukov, D., Vasenko, A. A., Veresnikova, A., Vignoli, C., von Sturm, K., Wester, T., Wiesinger, C., Wojcik, M., Yanovich, E., Zatschler, B., Zhitnikov, I., Zhukov, S. V., Zinatulina, D., Zschocke, A., Zsigmond, A. J., and Zuzel, K. Zuber G.

Subjects
High Energy Physics - Experiment, Nuclear Experiment
Abstract

We present the first search for bosonic super-WIMPs as keV-scale dark matter candidates performed with the GERDA experiment. GERDA is a neutrinoless double-beta decay experiment which operates high-purity germanium detectors enriched in $^{76}$Ge in an ultra-low background environment at the Laboratori Nazionali del Gran Sasso (LNGS) of INFN in Italy. Searches were performed for pseudoscalar and vector particles in the mass region from 60 keV/c$^2$ to 1 MeV/c$^2$. No evidence for a dark matter signal was observed, and the most stringent constraints on the couplings of super-WIMPs with masses above 120 keV/c$^2$ have been set. As an example, at a mass of 150 keV/c$^2$ the most stringent direct limits on the dimensionless couplings of axion-like particles and dark photons to electrons of $g_{ae} < 3 \cdot 10^{-12}$ and ${\alpha'}/{\alpha} < 6.5 \cdot 10^{-24}$ at 90% credible interval, respectively, were obtained., Comment: 6 pages, 3 figures, submitted to Physical Review Letters, added list of authors, updated ref. [21]

Published
2020
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24. Search for tri-nucleon decays of 76Ge in GERDA

Author

Agostini, M., Alexander, A., Araujo, G., Bakalyarov, A. M., Balata, M., Barabanov, I., Baudis, L., Bauer, C., Belogurov, S., Bettini, A., Bezrukov, L., Biancacci, V., Bossio, E., Bothe, V., Brugnera, R., Caldwell, A., Calgaro, S., Cattadori, C., Chernogorov, A., Chiu, P.-J., Comellato, T., D’Andrea, V., Demidova, E. V., Di Giacinto, A., Di Marco, N., Doroshkevich, E., Fischer, F., Fomina, M., Gangapshev, A., Garfagnini, A., Gooch, C., Grabmayr, P., Gurentsov, V., Gusev, K., Hakenmüller, J., Hemmer, S., Hofmann, W., Hult, M., Inzhechik, L. V., Janicskó Csáthy, J., Jochum, J., Junker, M., Kazalov, V., Kermaïdic, Y., Khushbakht, H., Kihm, T., Kilgus, K., Kirpichnikov, I. V., Klimenko, A., Knöpfle, K. T., Kochetov, O., Kornoukhov, V. N., Krause, P., Kuzminov, V. V., Laubenstein, M., Lindner, M., Lippi, I., Lubashevskiy, A., Lubsandorzhiev, B., Lutter, G., Macolino, C., Majorovits, B., Maneschg, W., Manzanillas, L., Marshall, G., Misiaszek, M., Morella, M., Müller, Y., Nemchenok, I., Neuberger, M., Pandola, L., Pelczar, K., Pertoldi, L., Piseri, P., Pullia, A., Rauscher, L., Redchuk, M., Riboldi, S., Rumyantseva, N., Sada, C., Sailer, S., Salamida, F., Schönert, S., Schreiner, J., Schütt, M., Schütz, A.-K., Schulz, O., Schwarz, M., Schwingenheuer, B., Selivanenko, O., Shevchik, E., Shirchenko, M., Shtembari, L., Simgen, H., Smolnikov, A., Stukov, D., Sullivan, S., Vasenko, A. A., Veresnikova, A., Vignoli, C., von Sturm, K., Wester, T., Wiesinger, C., Wojcik, M., Yanovich, E., Zatschler, B., Zhitnikov, I., Zhukov, S. V., Zinatulina, D., Zschocke, A., Zsigmond, A. J., Zuber, K., and Zuzel, G.

Published
2023
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25. Probing Majorana neutrinos with double-$\beta$ decay

Author

GERDA collaboration, Agostini, M., Bakalyarov, A. M., Balata, M., Barabanov, I., Baudis, L., Bauer, C., Bellotti, E., Belogurov, S., Bettini, A., Bezrukov, L., Borowicz, D., Brudanin, V., Brugnera, R., Caldwell, A., Cattadori, C., Chernogorov, A., Comellato, T., D'Andrea, V., Demidova, E. V., Di Marco, N., Domula, A., Doroshkevich, E., Egorov, V., Falkenstein, R., Fomina, M., Gangapshev, A., Garfagnini, A., Giordano, M., Grabmayr, P., Gurentsov, V., Gusev, K., Hakenmüller, J., Hegai, A., Heisel, M., Hemmer, S., Hiller, R., Hofmann, W., Hult, M., Inzhechik, L. V., Csáthy, J. Janicskó, Jochum, J., Junker, M., Kazalov, V., Kermaïdic, Y., Kihm, T., Kirpichnikov, I. V., Kirsch, A., Kish, A., Klimenko, A., Kneißl, R., Knöpfle, K. T., Kochetov, O., Kornoukhov, V. N., Krause, P., Kuzminov, V. V., Laubenstein, M., Lazzaro, A., Lindner, M., Lippi, I., Lubashevskiy, A., Lubsandorzhiev, B., Lutter, G., Macolino, C., Majorovits, B., Maneschg, W., Miloradovic, M., Mingazheva, R., Misiaszek, M., Moseev, P., Nemchenok, I., Panas, K., Pandola, L., Pelczar, K., Pertoldi, L., Piseri, P., Pullia, A., Ransom, C., Riboldi, S., Rumyantseva, N., Sada, C., Sala, E., Salamida, F., Schmitt, C., Schneider, B., Schönert, S., Schütz, A. -K., Schulz, O., Schwingenheuer, B., Schwarz, M., Selivanenko, O., Shevchik, E., Shirchenko, M., Simgen, H., Smolnikov, A., Stanco, L., Stukov, D., Vanhoefer, L., Vasenko, A. A., Veresnikova, A., von Sturm, K., Wagner, V., Wegmann, A., Wester, T., Wiesinger, C., Wojcik, M., Yanovich, E., Zhitnikov, I., Zhukov, S. V., Zinatulina, D., Zschocke, A., Zsigmond, A. J., Zuber, K., and Zuzel, G.

Subjects
High Energy Physics - Experiment, Nuclear Experiment
Abstract

A discovery that neutrinos are not the usual Dirac but Majorana fermions, i.e. identical to their antiparticles, would be a manifestation of new physics with profound implications for particle physics and cosmology. Majorana neutrinos would generate neutrinoless double-$\beta$ ($0\nu\beta\beta$) decay, a matter-creating process without the balancing emission of antimatter. So far, 0$\nu\beta\beta$ decay has eluded detection. The GERDA collaboration searches for the $0\nu\beta\beta$ decay of $^{76}$Ge by operating bare germanium detectors in an active liquid argon shield. With a total exposure of 82.4 kg$\cdot$yr, we observe no signal and derive a lower half-life limit of T$_{1/2}$ > 0.9$\cdot$10$^{26}$ yr (90% C.L.). Our T$_{1/2}$ sensitivity assuming no signal is 1.1$\cdot$10$^{26}$ yr. Combining the latter with those from other $0{\nu}\beta\beta$ decay searches yields a sensitivity to the effective Majorana neutrino mass of 0.07 - 0.16 eV, with corresponding sensitivities to the absolute mass scale in $\beta$ decay of 0.15 - 0.44 eV, and to the cosmological relevant sum of neutrino masses of 0.46 - 1.3 eV., Comment: Authors' main+supplementary text: 13+28 pages, 3+12 figures, 1+7 tables. Definite version to be published in Science

Published
2019
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26. 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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27. Characterization of 30 $^{76}$Ge enriched Broad Energy Ge detectors for GERDA Phase II

Author

GERDA collaboration, Agostini, M., Bakalyarov, A. M., Andreotti, E., Balata, M., Barabanov, I., Baudis, L., Barros, N., Bauer, C., Bellotti, E., Belogurov, S., Benato, G., Bettini, A., Bezrukov, L., Bode, T., Borowicz, D., Brudanin, V., Brugnera, R., Budjáš, D., Caldwell, A., Cattadori, C., Chernogorov, A., D'Andrea, V., Demidova, E. V., Di Marco, N., Domula, A., Doroshkevich, E., Egorov, V., Falkenstein, R., Freund, K., Gangapshev, A., Garfagnini, A., Gooch, C., Grabmayr, P., Gurentsov, V., Gusev, K., Hakenmüller, J., Hegai, A., Heisel, M., Hemmer, S., Hiller, R., Hofmann, W., Hult, M., Inzhechik, L. V., Csáthy, J. Janicskó, Jochum, J., Junker, M., Kazalov, V., Kermaidic, Y., Kihm, T., Kirpichnikov, I. V., Kirsch, A., Kish, A., Klimenko, A., Kneißl, R., Knöpfle, K. T., Kochetov, O., Kornoukhov, V. N., Kuzminov, V. V., Laubenstein, M., Lazzaro, A., Lehnert, B., Liao, Y., Lindner, M., Lippi, I., Lubashevskiy, A., Lubsandorzhiev, B., Lutter, G., Macolino, C., Majorovits, B., Maneschg, W., Miloradovic, M., Mingazheva, R., Misiaszek, M., Moseev, P., Nemchenok, I., Panas, K., Pandola, L., Pelczar, K., Pullia, A., Ransom, C., Riboldi, S., Rumyantseva, N., Sada, C., Salamida, F., Salathe, M., Schmitt, C., Schneider, B., Schönert, S., Schütz, A-K., Schulz, O., Schwingenheuer, B., Selivanenko, O., Shevchik, E., Shirchenko, M., Simgen, H., Smolnikov, A., Stanco, L., Ur, C. A., Vanhoefer, L., Vasenko, A. A., Veresnikova, A., von Sturm, K., Wagner, V., Wegmann, A., Wester, T., Wiesinger, C., Wojcik, M., Yanovich, E., Zhitnikov, I., Zhukov, S. V., Zinatulina, D., Zsigmond, A. J., Zuber, K., and Zuzel, G.

Subjects
Physics - Instrumentation and Detectors
Abstract

The GERmanium Detector Array (GERDA) is a low background experiment located at the Laboratori Nazionali del Gran Sasso in Italy, which searches for neutrinoless double beta decay of $^{76}$Ge into $^{76}$Se+2e$^-$. GERDA has been conceived in two phases. Phase II, which started in December 2015, features several novelties including 30 new Ge detectors. These were manufactured according to the Broad Energy Germanium (BEGe) detector design that has a better background discrimination capability and energy resolution compared to formerly widely-used types. Prior to their installation, the new BEGe detectors were mounted in vacuum cryostats and characterized in detail in the HADES underground laboratory in Belgium. This paper describes the properties and the overall performance of these detectors during operation in vacuum. The characterization campaign provided not only direct input for GERDA Phase II data collection and analyses, but also allowed to study detector phenomena, detector correlations as well as to test the strength of pulse shape simulation codes., Comment: 29 pages, 18 figures

Published
2019
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28. 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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29. Initial results from the Majorana Demonstrator

Author

Caldwell, TS, Abgrall, N, Alvis, SI, Arnquist, IJ, Avignone, FT, Barabash, AS, Barton, CJ, Bertrand, FE, Bode, T, Bos, B, Bradley, AW, Brudanin, V, Busch, M, Buuck, M, Chan, YDC, Christofferson, CD, Chu, PH, Cuesta, C, Detwiler, JA, Dunagan, C, Efremenko, Y, Ejiri, H, Elliott, SR, Gilliss, T, Giovanetti, GK, Green, MP, Gruszko, J, Guinn, IS, Guiseppe, VE, Haufe, CR, Hehn, L, Henning, R, Hoppe, EW, Howe, MA, Keeter, KJ, Kidd, MF, Konovalov, SI, Kouzes, RT, Lopez, AM, Martin, RD, Massarczyk, R, Meijer, SJ, Mertens, S, Myslik, J, O'Shaughnessy, C, Othman, G, Pettus, W, Poon, AWP, Radford, DC, Rager, J, Reine, AL, Rielage, K, Robertson, RGH, Ruof, NW, Shanks, B, Shirchenko, M, Suriano, AM, Tedeschi, D, Trimble, JE, Varner, RL, Vasilyev, S, Vetter, K, Vorren, K, White, BR, Wilkerson, JF, Wiseman, C, Xu, W, Yakushev, E, Yu, CH, Yumatov, V, Zhitnikov, I, and Zhu, BX

Subjects
physics.ins-det, nucl-ex, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Condensed Matter Physics, Other Physical Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics
Abstract

The Majorana Collaboration has assembled an array of high purity Ge detectors to search for neutrinoless double-beta decay in 76Ge 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 76Ge) 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.

Published
2020

30. Spectral analysis for the Majorana Demonstrator experiment

Author

Hehn, L, Abgrall, N, Alvis, SI, Arnquist, IJ, Avignone, FT, Barabash, AS, Barton, CJ, Bertrand, FE, Bode, T, Bradley, AW, Brudanin, V, Busch, M, Buuck, M, Caldwell, TS, Chan, YD, Christofferson, CD, Chu, PH, Cuesta, C, Detwiler, JA, Dunagan, C, Efremenko, Y, Ejiri, H, Elliott, SR, Gilliss, T, Giovanetti, GK, Green, MP, Gruszko, J, Guinn, IS, Guiseppe, VE, Haufe, CR, Henning, R, Hoppe, EW, Howe, MA, Keeter, KJ, Kidd, MF, Konovalov, SI, Kouzes, RT, Lopez, AM, Martin, RD, Massarczyk, R, Meijer, SJ, Mertens, S, Myslik, J, O'Shaughnessy, C, Othman, G, Pettus, W, Poon, AWP, Radford, DC, Rager, J, Reine, AL, Rielage, K, Robertson, RGH, Ruof, NW, Shanks, B, Shirchenko, M, Suriano, AM, Tedeschi, D, Trimble, JE, Varner, RL, Vasilyev, S, Vetter, K, Vorren, K, White, BR, Wilkerson, JF, Wiseman, C, Xu, W, Yakushev, E, Yu, CH, Yumatov, V, Zhitnikov, I, and Zhu, BX

Subjects
physics.ins-det, nucl-ex, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Condensed Matter Physics, Other Physical Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics
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 detectors totaling 44.1kg (29.7kg enriched detectors), located at the 4850' level of the Sanford Underground Research Facility in Lead, South Dakota, USA. Data taken with this setup since summer 2015 at different construction stages of the experiment show a clear reduction of the observed background index around the ROI for 0νββ-decay search due to improvements in shielding. We discuss the statistical approaches to search for a νββ-signal and derive the physics sensitivity for an expected exposure of 10kg• y from enriched detectors using a profile likelihood based hypothesis test in combination with toy Monte Carlo data.

Published
2020

31. Progress Toward A 2νββ Measurement for the Majorana Demonstrator

Author

Gilliss, T, Abgrall, N, Alvis, SI, Arnquist, IJ, Avignone, FT, Barabash, AS, Barton, CJ, Bertrand, FE, Bode, T, Bradley, AW, Brudanin, V, Busch, M, Buuck, M, Caldwell, TS, Chan, YD, Christofferson, CD, Chu, PH, Cuesta, C, Detwiler, JA, Dunagan, C, Efremenko, Y, Ejiri, H, Elliott, SR, Giovanetti, GK, Green, MP, Gruszko, J, Guinn, IS, Guiseppe, VE, Haufe, CR, Hehn, L, Henning, R, Hoppe, EW, Howe, MA, Keeter, KJ, Kidd, MF, Konovalov, SI, Kouzes, RT, Lopez, AM, Martin, RD, Massarczyk, R, Meijer, SJ, Mertens, S, Myslik, J, O'Shaughnessy, C, Othman, G, Pettus, W, Poon, AWP, Radford, DC, Rager, J, Reine, AL, Rielage, K, Robertson, RGH, Ruof, NW, Shanks, B, Shirchenko, M, Suriano, AM, Tedeschi, D, Trimble, JE, Varner, RL, Vasilyev, S, Vetter, K, Vorren, K, White, BR, Wilkerson, JF, Wiseman, C, Xu, W, Yakushev, E, Yu, CH, Yumatov, V, Zhitnikov, I, and Zhu, BX

Subjects
physics.ins-det, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Condensed Matter Physics, Other Physical Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics
Abstract

The MAJORANA DEMONSTRATOR is a 76Ge-based neutrinoless double-beta decay (0νββ) 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 (2νββ) of 76Ge. For Ge detectors, having superior energy resolution (0.1%), this mode poses negligible background to the 0νββ mode, even for a ton-scale experiment. However, the measurement of the 2νββ mode allows for careful systematics checks of active detector mass, enrichment fraction, and pulse shape discrimination cuts related to both the 0νββ and 2νββ decay modes. A precision measurement of the 2νββ shape also allows searches for spectral distortions, possibly indicative of new physics, including 0νββχ. Work is underway to construct a full experimental background model enabling a Bayesian fit to the measured energy spectrum and extraction of a precise 2νββ spectrum and half-life.

Published
2020

32. Design improvements to cables and connectors in the Majorana Demonstrator

Author

Haufe, CR, Reine, AL, Abgrall, N, Alvis, SI, Arnquist, IJ, Avignone, FT, Barabash, AS, Barton, CJ, Bertrand, FE, Bode, T, Bradley, AW, Brudanin, V, Busch, M, Buuck, M, Caldwell, TS, Chan, YD, Christofferson, CD, Chu, PH, Cuesta, C, Detwiler, JA, Dunagan, C, Efremenko, Y, Ejiri, H, Elliott, SR, Gilliss, T, Giovanetti, GK, Green, MP, Gruszko, J, Guinn, IS, Guiseppe, VE, Hehn, L, Henning, R, Hoppe, EW, Howe, MA, Keeter, KJ, Kidd, MF, Konovalov, SI, Kouzes, RT, Lopez, AM, Martin, RD, Massarczyk, R, Meijer, SJ, Mertens, S, Myslik, J, O'Shaughnessy, C, Othman, G, Pettus, W, Poon, AWP, Radford, DC, Rager, J, Rielage, K, Robertson, RGH, Ruof, NW, Shanks, B, Shirchenko, M, Suriano, AM, Tedeschi, D, Trimble, JE, Varner, RL, Vasilyev, S, Vetter, K, Vorren, K, White, BR, Wilkerson, JF, Wiseman, C, Xu, W, Yakushev, E, Yu, CH, Yumatov, V, Zhitnikov, I, and Zhu, BX

Subjects
physics.ins-det, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Condensed Matter Physics, Other Physical Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics
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 each detectors point contact. 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.

Published
2020

33. Data quality assurance for the Majorana Demonstrator

Author

Myslik, J, Abgrall, N, Alvis, SI, Arnquist, IJ, Avignone, FT, Barabash, AS, Barton, CJ, Bertrand, FE, Bode, T, Bradley, AW, Brudanin, V, Busch, M, Buuck, M, Caldwell, TS, Chan, YD, Christofferson, CD, Chu, PH, Cuesta, C, Detwiler, JA, Dunagan, C, Efremenko, Y, Ejiri, H, Elliott, SR, Gilliss, T, Giovanetti, GK, Green, MP, Gruszko, J, Guinn, IS, Guiseppe, VE, Haufe, CR, Hehn, L, Henning, R, Hoppe, EW, Howe, MA, Keeter, KJ, Kidd, MF, Konovalov, SI, Kouzes, RT, Lopez, AM, Martin, RD, Massarczyk, R, Meijer, SJ, Mertens, S, O'Shaughnessy, C, Othman, G, Pettus, W, Poon, AWP, Radford, DC, Rager, J, Reine, AL, Rielage, K, Robertson, RGH, Ruof, NW, Shanks, B, Shirchenko, M, Suriano, AM, Tedeschi, D, Trimble, JE, Varner, RL, Vasilyev, S, Vetter, K, Vorren, K, White, BR, Wilkerson, JF, Wiseman, C, Xu, W, Yakushev, E, Yu, CH, Yumatov, V, Zhitnikov, I, and Zhu, BX

Subjects
physics.ins-det, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Condensed Matter Physics, Other Physical Sciences
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.

Published
2020

34. Status update of the majorana demonstrator neutrinoless double beta decay experiment

Author

Gruszko, J, Buuck, M, Cuesta, C, Detwiler, JA, Guinn, IS, Leon, J, Robertson, RGH, Abgrall, N, Bradley, AW, Chan, YD, Mertens, S, Poon, AWP, Arnquist, IJ, Hoppe, EW, Kouzes, RT, LaFerriere, BD, Orrell, JL, Avignone, FT, Barabash, AS, Konovalov, SI, Yumatov, V, Bertrand, FE, Galindo-Uribarri, A, Radford, DC, Varner, RL, White, BR, Yu, CH, Brudanin, V, Shirchenko, M, Vasilyev, S, Yakushev, E, Zhitnikov, I, Busch, M, Byram, D, Jasinski, BR, Snyder, N, Caldwell, AS, Christofferson, CD, Dunagan, C, Howard, S, Suriano, AM, Chu, PH, Elliott, SR, Goett, J, Massarczyk, R, Rielage, K, Xu, W, Efremenko, Y, Ejiri, H, Gilliss, T, Giovanetti, GK, Henning, R, Howe, MA, MacMullin, J, Meijer, SJ, O'Shaughnessy, C, Rager, J, Shanks, B, Trimble, JE, Vorren, K, Green, MP, Guiseppe, VE, Tedeschi, D, Wiseman, C, Keeter, KJ, Kidd, MF, Martin, RD, Romero-Romero, E, Vetter, K, and Wilkerson, JF

Subjects
physics.ins-det, nucl-ex
Abstract

Neutrinoless double beta decay searches play a major role in determining neutrino properties, in particular the Majorana or Dirac nature of the neutrino and the absolute scale of the neutrino mass. The consequences of these searches go beyond neutrino physics, with implications for Grand Unification and leptogenesis. The Majorana Collaboration is assembling a low-background array of high purity Germanium (HPGe) detectors to search for neutrinoless double-beta decay in 76Ge. The Majorana Demonstrator, which is currently being constructed and commissioned at the Sanford Underground Research Facility in Lead, South Dakota, will contain 44 kg (30 kg enriched in 76Ge) of HPGe detectors. Its primary goal is to demonstrate the scalability and background required for a tonne-scale Ge experiment. This is accomplished via a modular design and projected background of less than 3 cnts/tonne-yr in the region of interest. The experiment is currently taking data with the first of its enriched detectors.

Published
2020

35. 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

36. 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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37. Liquid argon light collection and veto modeling in GERDA Phase II

Author

Agostini, M., Alexander, A., Araujo, G. R., Bakalyarov, A. M., Balata, M., Barabanov, I., Baudis, L., Bauer, C., Belogurov, S., Bettini, A., Bezrukov, L., Biancacci, V., Bossio, E., Bothe, V., Brugnera, R., Caldwell, A., Calgaro, S., Cattadori, C., Chernogorov, A., Chiu, P. -J., Comellato, T., D’Andrea, V., Demidova, E. V., Di Giacinto, A., Di Marco, N., Doroshkevich, E., Fischer, F., Fomina, M., Gangapshev, A., Garfagnini, A., Gooch, C., Grabmayr, P., Gurentsov, V., Gusev, K., Hakenmüller, J., Hemmer, S., Hofmann, W., Hult, M., Inzhechik, L. V., Csáthy, J. Janicskó, Jochum, J., Junker, M., Kazalov, V., Kermaïdic, Y., Khushbakht, H., Kihm, T., Kilgus, K., Kirpichnikov, I. V., Klimenko, A., Knöpfle, K. T., Kochetov, O., Kornoukhov, V. N., Krause, P., Kuzminov, V. V., Laubenstein, M., Lehnert, B., Lindner, M., Lippi, I., Lubashevskiy, A., Lubsandorzhiev, B., Lutter, G., Macolino, C., Majorovits, B., Maneschg, W., Manzanillas, L., Marshall, G., Miloradovic, M., Mingazheva, R., Misiaszek, M., Morella, M., Müller, Y., Nemchenok, I., Neuberger, M., Pandola, L., Pelczar, K., Pertoldi, L., Piseri, P., Pullia, A., Rauscher, L., Redchuk, M., Riboldi, S., Rumyantseva, N., Sada, C., Sailer, S., Salamida, F., Schönert, S., Schreiner, J., Schütt, M., Schütz, A. -K., Schulz, O., Schwarz, M., Schwingenheuer, B., Selivanenko, O., Shevchik, E., Shirchenko, M., Shtembari, L., Simgen, H., Smolnikov, A., Stukov, D., Sullivan, S., Vasenko, A. A., Veresnikova, A., Vignoli, C., von Sturm, K., Wegmann, A., Wester, T., Wiesinger, C., Wojcik, M., Yanovich, E., Zatschler, B., Zhitnikov, I., Zhukov, S. V., Zinatulina, D., Zschocke, A., Zsigmond, A. J., Zuber, K., and Zuzel, G.

Published
2023
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39. Search for sterile neutrinos at the DANSS experiment

Author

Alekseev, I., Belov, V., Brudanin, V., Danilov, M., Egorov, V., Filosofov, D., Fomina, M., Hons, Z., Kazartsev, S., Kobyakin, A., Kuznetsov, A., Machikhiliyan, I., Medvedev, D., Nesterov, V., Olshevsky, A., Pogorelov, N., Ponomarev, D., Rozova, I., Rumyantseva, N., Rusinov, V., Samigullin, E., Shevchik, Ye., Shirchenko, M., Shitov, Yu., Skrobova, N., Starostin, A., Svirida, D., Tarkovsky, E., Vlášek, J., Zhitnikov, I., and Zinatulina, D.

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

DANSS is a highly segmented 1~m${}^3$ plastic scintillator detector. Its 2500 one meter long scintillator strips have a Gd-loaded reflective cover. The DANSS detector is placed under an industrial 3.1~$\mathrm{GW_{th}}$ reactor of the Kalinin Nuclear Power Plant 350~km NW from Moscow. The distance to the core is varied on-line from 10.7~m to 12.7~m. The reactor building provides about 50~m water-equivalent shielding against the cosmic background. DANSS detects almost 5000 $\widetilde\nu_e$ per day at the closest position with the cosmic background less than 3$\%$. The inverse beta decay process is used to detect $\widetilde\nu_e$. Sterile neutrinos are searched for assuming the $4\nu$ model (3 active and 1 sterile $\nu$). The exclusion area in the $\Delta m_{14}^2,\sin^22\theta_{14}$ plane is obtained using a ratio of positron energy spectra collected at different distances. Therefore results do not depend on the shape and normalization of the reactor $\widetilde\nu_e$ spectrum, as well as on the detector efficiency. Results are based on 966 thousand antineutrino events collected at 3 distances from the reactor core. The excluded area covers a wide range of the sterile neutrino parameters up to $\sin^22\theta_{14}<0.01$ in the most sensitive region., Comment: 10 pages, 13 figures, version accepted for publication

Published
2018
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40. 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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41. Improved limit on neutrinoless double beta decay of $^{76}$Ge from GERDA Phase II

Author

Agostini, M., Bakalyarov, A. M., Balata, M., Barabanov, I., Baudis, L., Bauer, C., Bellotti, E., Belogurov, S., Bettini, A., Bezrukov, L., Biernat, J., Bode, T., Borowicz, D., Brudanin, V., Brugnera, R., Caldwell, A., Cattadori, C., Chernogorov, A., Comellato, T., D'Andrea, V., Demidova, E. V., Di Marco, N., Domula, A., Doroshkevich, E., Egorov, V., Falkenstein, R., Gangapshev, A., Garfagnini, A., Grabmayr, P., Gurentsov, V., Gusev, K., Hakenmüller, J., Hegai, A., Heisel, M., Hemmer, S., Hiller, R., Hofmann, W., Hult, M., Inzhechik, L. V., Csáthy, J. Janicskó, Jochum, J., Junker, M., Kazalov, V., Kermaidic, Y., Kihm, T., Kirpichnikov, I. V., Kirsch, A., Kish, A., Klimenko, A., Kneißl, R., Knöpfle, K. T., Kochetov, O., Kornoukhov, V. N., Kuzminov, V. V., Laubenstein, M., Lazzaro, A., Lindner, M., Lippi, I., Lubashevskiy, A., Lubsandorzhiev, B., Lutter, G., Macolino, C., Majorovits, B., Maneschg, W., Miloradovic, M., Mingazheva, R., Misiaszek, M., Moseev, P., Nemchenok, I., Panas, K., Pandola, L., Pelczar, K., Pertoldi, L., Pullia, A., Ransom, C., Riboldi, S., Rumyantseva, N., Sada, C., Salamida, F., Schmitt, C., Schneider, B., Schönert, S., Schütz, A-K., Schulz, O., Schwingenheuer, B., Selivanenko, O., Shevchik, E., Shirchenko, M., Simgen, H., Smolnikov, A., Stanco, L., Vanhoefer, L., Vasenko, A. A., Veresnikova, A., von Sturm, K., Wagner, V., Wegmann, A., Wester, T., Wiesinger, C., Wojcik, M., Yanovich, E., Zhitnikov, I., Zhukov, S. V., Zinatulina, D., Zschocke, A., Zsigmond, A. J., Zuber, K., and Zuzel, G.

Subjects
Nuclear Experiment, Physics - Instrumentation and Detectors
Abstract

The GERDA experiment searches for the lepton number violating neutrinoless double beta decay of $^{76}$Ge ($^{76}$Ge $\rightarrow$ $^{76}$Se + 2e$^-$) operating bare Ge diodes with an enriched $^{76}$Ge fraction in liquid argon. The exposure for BEGe-type detectors is increased threefold with respect to our previous data release. The BEGe detectors feature an excellent background suppression from the analysis of the time profile of the detector signals. In the analysis window a background level of $1.0_{-0.4}^{+0.6}\cdot10^{-3}$ cts/(keV$\cdot$kg$\cdot$yr) has been achieved; if normalized to the energy resolution this is the lowest ever achieved in any 0$\nu\beta\beta$ experiment. No signal is observed and a new 90 \% C.L. lower limit for the half-life of $8.0\cdot10^{25}$ yr is placed when combining with our previous data. The median expected sensitivity assuming no signal is $5.8\cdot10^{25}$ yr., Comment: 5 pages, 2 figures

Published
2018
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42. 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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43. 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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44. 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

45. Recent results of the Majorana Demonstrator experiment

Author

López-Castaño, JM, Alvis, SI, Arnquist, IJ, Avignone, FT, Barabash, AS, Barton, CJ, Basu, V, Bertrand, FE, Bos, B, Brudanin, V, Busch, M, Buuck, M, Caldwell, TS, Chan, Y-D, Christofferson, CD, Chu, P-H, Clark, ML, Cuesta, C, Detwiler, JA, Drobizhev, A, Edwins, DW, Efremenko, Yu, Ejiri, H, Elliott, SR, Gilliss, T, Giovanetti, GK, Green, MP, Gruszko, J, Guinn, IS, Guiseppe, VE, Haufe, CR, Hegedus, RJ, Henning, R, Aguilar, D Hervas, Hoppe, EW, Hostiuc, A, Howe, MA, Keeter, KJ, Kidd, MF, Konovalov, SI, Kouzes, RT, Lopez, AM, Martin, E, Martin, RD, Massarczyk, R, Meijer, SJ, Mertens, S, Myslik, J, Oli, TK, Othman, G, Pettus, W, Piliounis, A, Poon, AWP, Radford, DC, Rager, J, Reine, AL, Rielage, K, Ruof, NW, Shanks, B, Shirchenko, M, Tedeschi, D, Varner, RL, Vasilyev, S, White, BR, Wilkerson, JF, Wiseman, C, Xu, W, Yakushev, E, Yu, C-H, Yumatov, V, Zhitnikov, I, and Zhu, BX

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

The Majorana Demonstrator is searching for neutrinoless double-beta decay in 76Ge with two modular arrays of natural and 76Ge-enriched germanium detectors. It is located at the 4850' level of Sanford Underground Research Facility in Lead, South Dakota, USA, and its total mass of germanium detectors is 44.1 kg, of which 29.7 kg is enriched. The analysis of the first 26 kg-yr of data provides an unprecedented energy resolution of 0.13% in the region of interest at 2039 keV and a background level of 15.4 ±2.0 counts/(FWHM t yr). It establishes the lower limit of the half-life of neutrinoless double beta decay as 2.7 1025 yr in 76Ge at 90% CL. This analysis will be summarized here with an emphasis on the energy determination.

Published
2019

46. Search for neutrinoless double- β decay in Ge 76 with 26 kg yr of exposure from the M ajorana D emonstrator SEARCH for NEUTRINOLESS DOUBLE- β DECAY ... S. I. ALVIS et al.

Author

Cuesta, C, Alvis, SI, Arnquist, IJ, Avignone, FT, Barabash, AS, Barton, CJ, Basu, V, Bertrand, FE, Bos, B, Busch, M, Buuck, M, Caldwell, TS, Chan, YD, Christofferson, CD, Chu, PH, Clark, M, Detwiler, JA, Efremenko, Y, Ejiri, H, Elliott, SR, Gilliss, T, Giovanetti, GK, Green, MP, Gruszko, J, Guinn, IS, Guiseppe, VE, Haufe, CR, Hegedus, RJ, Hehn, L, Henning, R, Hervas Aguilar, D, Hoppe, EW, Howe, MA, Kidd, MF, Konovalov, SI, Kouzes, RT, Lopez, AM, Martin, RD, Massarczyk, R, Meijer, SJ, Mertens, S, Myslik, J, Othman, G, Pettus, W, Piliounis, A, Poon, AWP, Radford, DC, Rager, J, Reine, AL, Rielage, K, Ruof, NW, Shanks, B, Shirchenko, M, Tedeschi, D, Varner, RL, Vasilyev, S, White, BR, Wilkerson, JF, Wiseman, C, Xu, W, Yakushev, E, Yu, CH, Yumatov, V, Zhitnikov, I, and Zhu, BX

Subjects
nucl-ex, hep-ex
Abstract

The Majorana Collaboration is operating an array of high-purity Ge detectors to search for the neutrinoless double-β decay of Ge76. The Majorana Demonstrator consists of 44.1 kg of Ge detectors (29.7 kg enriched to 88% in Ge76) split between two modules constructed from ultraclean 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-β decay in Ge76 with 26.0±0.5 kg yr of enriched exposure. With the Demonstrator's energy resolution of 2.53 keV FWHM at Qββ, which is the best among all neutrinoless double-β decay experiments, 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 Ge76 neutrinoless double-β decay half-life of 2.7×1025 yr [90% confidence level (CL)] with a median sensitivity of 4.8×1025 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 configurations with full shielding and optimized grounding is 11.9±2.0 counts/(FWHM t yr).

Published
2019

47. Recent results from the MAJORANA DEMONSTRATOR

Author

Myslik, Jordan, Alvis, SI, Arnquist, IJ, Avignone III, FT, Barabash, AS, Barton, CJ, Bertrand, FE, Bode, T, Bos, B, Brudanin, V, Busch, M, Buuck, M, Caldwell, TS, Chan, Y-D, Christofferson, CD, Chu, P-H, Cuesta, C, Detwiler, JA, Dunagan, C, Efremenko, Yu, Ejiri, H, Elliott, SR, Gilliss, T, Giovanetti, GK, Green, MP, Gruszko, J, Guinn, IS, Guiseppe, VE, Haufe, CR, Hegedus, RJ, Hehn, L, Henning, R, Hervas Aguilar, D, Hoppe, EW, Howe, MA, Keeter, KJ, Kidd, MF, Konovalov, SI, Kouzes, RT, Lopez, AM, Martin, RD, Massarczyk, R, Meijer, SJ, Mertens, S, Othman, G, Pettus, W, Piliounis, A, Poon, AWP, Radford, DC, Rager, J, Reine, AL, Rielage, K, Ruof, NW, Shanks, B, Shirchenko, M, Tedeschi, D, Varner, RL, Vasilyev, S, Vasundhara, White, BR, Wilkerson, JF, Wiseman, C, Xu, W, Yakushev, E, Yu, C-H, Yumatov, V, Zhitnikov, I, and Zhu, BX

Abstract

The MAJORANA DEMONSTRATOR is an experiment constructed to search for neutrinoless double-beta decay in 76Ge 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 76Ge-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 76Ge experiment.

Published
2019

48. Search for neutrinoless double-β decay in Ge76 with 26 kg yr of exposure from the Majorana Demonstrator

Author

Alvis, SI, Arnquist, IJ, Avignone, FT, Barabash, AS, Barton, CJ, Basu, V, Bertrand, FE, Bos, B, Busch, M, Buuck, M, Caldwell, TS, Chan, Y-D, Christofferson, CD, Chu, P-H, Clark, M, Cuesta, C, Detwiler, JA, Efremenko, Yu, Ejiri, H, Elliott, SR, Gilliss, T, Giovanetti, GK, Green, MP, Gruszko, J, Guinn, IS, Guiseppe, VE, Haufe, CR, Hegedus, RJ, Hehn, L, Henning, R, Aguilar, D Hervas, Hoppe, EW, Howe, MA, Kidd, MF, Konovalov, SI, Kouzes, RT, Lopez, AM, Martin, RD, Massarczyk, R, Meijer, SJ, Mertens, S, Myslik, J, Othman, G, Pettus, W, Piliounis, A, Poon, AWP, Radford, DC, Rager, J, Reine, AL, Rielage, K, Ruof, NW, Shanks, B, Shirchenko, M, Tedeschi, D, Varner, RL, Vasilyev, S, White, BR, Wilkerson, JF, Wiseman, C, Xu, W, Yakushev, E, Yu, C-H, Yumatov, V, Zhitnikov, I, and Zhu, BX

Subjects
Nuclear and Plasma Physics, Particle and High Energy Physics, Physical Sciences, nucl-ex, hep-ex, Nuclear and plasma physics
Abstract

The Majorana Collaboration is operating an array of high-purity Ge detectors to search for the neutrinoless double-β decay of Ge76. The Majorana Demonstrator consists of 44.1 kg of Ge detectors (29.7 kg enriched to 88% in Ge76) split between two modules constructed from ultraclean 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-β decay in Ge76 with 26.0±0.5 kg yr of enriched exposure. With the Demonstrator's energy resolution of 2.53 keV FWHM at Qββ, which is the best among all neutrinoless double-β decay experiments, 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 Ge76 neutrinoless double-β decay half-life of 2.7×1025 yr [90% confidence level (CL)] with a median sensitivity of 4.8×1025 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 configurations with full shielding and optimized grounding is 11.9±2.0 counts/(FWHM t yr).

Published
2019

49. Multisite event discrimination for the majorana demonstrator

Author

Alvis, SI, Arnquist, IJ, Avignone, FT, Barabash, AS, Barton, CJ, Basu, V, Bertrand, FE, Bos, B, Buuck, M, Caldwell, TS, Chan, YD, Christofferson, CD, Chu, PH, Cuesta, C, Detwiler, JA, Ejiri, H, Elliott, SR, Gilliss, T, Giovanetti, GK, Green, MP, Gruszko, J, Guinn, IS, Guiseppe, VE, Haufe, CR, Hegedus, RJ, Hehn, L, Henning, R, Hervas Aguilar, D, Hoppe, EW, Howe, MA, Keeter, KJ, Kidd, MF, Konovalov, SI, Kouzes, RT, Lopez, AM, Martin, RD, Massarczyk, R, Meijer, SJ, Mertens, S, Myslik, J, Othman, G, Pettus, W, Piliounis, A, Poon, AWP, Radford, DC, Rager, J, Reine, AL, Rielage, K, Ruof, NW, Shanks, B, Shirchenko, M, Tedeschi, D, Varner, RL, Vasilyev, S, White, BR, Wilkerson, JF, Wiseman, C, Xu, W, Yakushev, E, Yu, CH, Yumatov, V, Zhitnikov, I, and Zhu, BX

Subjects
physics.ins-det, hep-ex, nucl-ex
Abstract

The Majorana Demonstrator is searching for neutrinoless double-beta decay (0νββ) in Ge76 using arrays of point-contact germanium detectors operating at the Sanford Underground Research Facility. Background results in the 0νββ 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 multisite 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 Th228 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 0νββ events, established using simulations.

Published
2019

50. Search for trinucleon decay in the Majorana Demonstrator

Author

Alvis, SI, Arnquist, IJ, Avignone, FT, Barabash, AS, Barton, CJ, Basu, V, Bertrand, FE, Bos, B, Brudanin, V, Busch, M, Buuck, M, Caldwell, TS, Chan, Y-D, Christofferson, CD, Chu, P-H, Cuesta, C, Detwiler, JA, Efremenko, Yu, Ejiri, H, Elliott, SR, Gilliss, T, Giovanetti, GK, Green, MP, Gruszko, J, Guinn, IS, Guiseppe, VE, Haufe, CR, Hegedus, RJ, Hehn, L, Henning, R, Aguilar, D Hervas, Hoppe, EW, Howe, MA, Keeter, KJ, Kidd, MF, Konovalov, SI, Kouzes, RT, Lopez, AM, Martin, RD, Massarczyk, R, Meijer, SJ, Mertens, S, Myslik, J, Othman, G, Pettus, W, Piliounis, A, Poon, AWP, Radford, DC, Rager, J, Reine, AL, Rielage, K, Ruof, NW, Shanks, B, Shirchenko, M, Tedeschi, D, Varner, RL, Vasilyev, S, White, BR, Wilkerson, JF, Wiseman, C, Xu, W, Yakushev, E, Yu, C-H, Yumatov, V, Zhitnikov, I, and Zhu, BX

Subjects
Nuclear and Plasma Physics, Particle and High Energy Physics, Synchrotrons and Accelerators, Physical Sciences, hep-ex, nucl-ex, physics.ins-det, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics, Nuclear & Particles Physics, Mathematical physics, Astronomical sciences, Particle and high energy physics
Abstract

The Majorana Demonstrator is an ultra-low-background experiment searching for neutrinoless double-beta decay in Ge76. 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 trinucleon decay-specific modes and invisible decay modes for Ge isotopes. We find a half-life limit of 4.9×1025 yr for the decay Ge76(ppn)→Zn73 e+π+ and 4.7×1025 yr for the decay Ge76(ppp)→Cu73 e+π+π+. The half-life limit for the invisible triproton decay mode of Ge76 was found to be 7.5×1024 yr.

Published
2019

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