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5 results on '"Alvis, S.I."'

1. 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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2. Search for neutrinoless double- β decay in Ge 76 with 26 kg yr of exposure from the Majorana Demonstrator

Author

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

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
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3. Search for trinucleon decay in the Majorana Demonstrator

Author

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

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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4. Multisite event discrimination for the majorana demonstrator

Author

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

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
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5. Search for Neutrinoless Double- β Decay in Ge 76 with the Majorana Demonstrator

Author

Christofferson, C.D., Finnerty, P., Chan, Y.-D., Haufe, C.R., Myslik, J., Tedeschi, D., Caldwell, T.S., Martin, R.D., Miller, M.L., Fuller, E., McDonald, A.B., Vetter, K., Amman, M., Aalseth, C.E., Zhu, B.X., Doe, P.J., Gruszko, J., Johnson, R.A., Othman, G., Zhitnikov, I., Lesko, K.T., Barbeau, P.S., Aguayo, E., Orrell, J.L., Leviner, L.E., Steele, D., Collar, J.I., Henning, R., Pushkin, K., Macmullin, S., Chu, P.-H., Wiseman, C., Bertrand, F.E., Suriano, A.M., Avignone, F.T., III, Fraenkle, F.M., Hehn, L., Meijer, S.J., Poon, A.W.P., Macmullin, J., Ruof, N.W., Lopez, A.M., Barton, C.J., Fujikawa, B.K., Kephart, J.D., Barabash, A.S., Yakushev, E., Marino, M.G., Dunmore, J.A., Green, M.P., Zimmermann, S., O'Shaughnessy, C., Bradley, A.W., Elliott, S.R., Tornow, W., Knecht, A., Hossbach, T.W., Bos, B., Rager, J., Ejiri, H., Young, A.R., Hoppe, E.W., Gehman, V.M., Guinn, I.S., Radford, D.C., Brodzinski, R.L., Shirchenko, M., Galindo-Uribarri, A., Mei, D.-M., Efremenko, Y., Loach, J.C., Fast, J.E., Merriman, J.H., Snavely, K.J., Overman, N.R., Phillips, D.G., II, Boswell, M., Rielage, K., Miley, H.S., Kouzes, R.T., Wilkerson, J.F., Xu, W., Reine, A.L., Ronquest, M.C., Brudanin, V., Varner, R.L., Konovalov, S.I., Detwiler, J.A., Kidd, M.F., Gilliss, T., Hallin, A.L., Arnquist, I.J., Pettus, W., Yaver, H., Abgrall, N., Massarczyk, R., Vasilyev, S., Howe, M.A., Shanks, B., Schubert, A.G., Back, H.O., Laferriere, B.D., Yu, C.-H., Jasinski, B.R., Goett, J., Luke, P.N., Snyder, N., Bode, T., Giovanetti, G.K., Vorren, K., Yumatov, V., Combs, D.C., Leon, J., Mertens, S., White, B.R., Reeves, J.H., Busch, M., Robertson, R.G.H., Keeter, K.J., Trimble, J.E., Barton, P.J., Cuesta, C., Caldwell, A.S., Cooper, R.J., Guiseppe, V.E., Alvis, S.I., Perumpilly, G., Buuck, M., and Fu, Z.

Abstract

The Majorana Collaboration is operating an array of high purity Ge detectors to search for neutrinoless double-β decay in Ge76. The Majorana Demonstrator comprises 44.1 kg of Ge detectors (29.7 kg enriched in Ge76) split between two modules contained in a low background shield at the Sanford Underground Research Facility in Lead, South Dakota. Here we present results from data taken during construction, commissioning, and the start of full operations. We achieve unprecedented energy resolution of 2.5 keV FWHM at Qββ and a very low background with no observed candidate events in 9.95 kg yr of enriched Ge exposure, resulting in a lower limit on the half-life of 1.9×1025 yr (90% C.L.). This result constrains the effective Majorana neutrino mass to below 240-520 meV, depending on the matrix elements used. In our experimental configuration with the lowest background, the background is 4.0-2.5+3.1 counts/(FWHM t yr).

Published
2018
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