221 research outputs found
Search for Pauli exclusion principle violating atomic transitions and electron decay with a p-type point contact germanium detector
No full textA search for Pauli-exclusion-principle-violating K-alpha electron transitions was performed using 89.5 kg-d of data collected with a p-type point contact high-purity germanium detector operated at the Kimballton Underground Research Facility. A lower limit on the transition lifetime of 5.8x10^30 seconds at 90% C.L. was set by looking for a peak at 10.6 keV resulting from the x-ray and Auger electrons present following the transition. A similar analysis was done to look for the decay of atomic K-shell electrons into neutrinos, resulting in a lower limit of 6.8x10^30 seconds at 90 C.L. It is estimated that the MAJORANA DEMONSTRATOR, a 44 kg array of p-type point contact detectors that will search for the neutrinoless double-beta decay of 76-Ge, could improve upon these exclusion limits by an order of magnitude after three years of operation. Abgrall, N; Arnquist, I J; Avignone, F T; Barabash, A S; Bertrand, F E; Bradley, A W; Brudanin, V; Busch, M; Buuck, M; Caldwell, A S; Chan, Y-D; Christofferson, C D; Chu, P -H; Cuesta, C; Detwiler, J A; Dunagan, C; Efremenko, Yu; Ejiri, H; Elliott, S R; Finnerty, P S; Galindo-Uribarri, A; Gilliss, T; Giovanetti, G K; Goett, J; Green, M P; Gruszko, J; Guinn, I S; Guiseppe, V E; Henning, R; Hoppe, E W; Howard, S; Howe, M A; Jasinski, B R; Keeter, K J; Kidd, M F; Konovalov, S I; Kouzes, R T; LaFerriere, B D; Leon, J; MacMullin, J; Martin, R D; Massarczyk, R; Meijer, S J; Mertens, S; Orrell, J L; O'Shaughnessy, C; Poon, A W P; Radford, D C; Rager, J; Rielage, K; Robertson, R G H; Romero-Romero, E; 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,
Search for the in-situ production of
No full textThe beta decay of Ge and Ge, both produced by neutron capture on Ge, is a potential background for Germanium based neutrinoless double-beta decay search experiments such as GERDA or the LEGEND experiment. In this work we present a search for Ge decays in the full GERDA Phase II data set. A delayed coincidence method was employed to identify the decay of Ge via the isomeric state of As (, , {T_{1/2} = {114}\,{\upmu }\hbox {s}}, As). New digital signal processing methods were employed to select and analyze pile-up signals. No signal was observed, and an upper limit on the production rate of Ge was set at nuc/(kg yr) (90% CL). This corresponds to a total production rate of Ge and Ge of nuc/(kg yr) (90% CL), assuming equal production rates. A previous Monte Carlo study predicted a value for in-situ Ge and Ge production of (0.21 ± 0.07) nuc/(kg.yr), a prediction that is now further corroborated by our experimental limit. Moreover, tagging the isomeric state of As can be utilised to further suppress the Ge background. Considering the similar experimental configurations of LEGEND-1000 and GERDA, the cosmogenic background in LEGEND-1000 at LNGS is estimated to remain at a sub-dominant level
GEMMA EXPERIMENT: THREE YEARS OF THE SEARCH FOR THE NEUTRINO MAGNETIC MOMENT
No full textThe result of the 3-year neutrino magnetic moment measurement at the Kalinin Nuclear Power Plant (KNPP) with the GEMMA spectrometer is presented. AntineutrinoÄelectron scattering is investigated. A high-purity germanium detector of 1.5 kg placed at a distance of 13.9 m from the 3 GW th reactor core is exposed to the antineutrino ux of 2.7 · 10 13 cm −2 · s −1 . The scattered electron spectra taken in (5184 + 6798) and (1853 + 1021) h for the reactor ON and OFF periods are compared. The upper limit for the neutrino magnetic moment μν < 3.2 · 10 −11 μB at 90% CL is derived from the data processing. ‚ · ¡μÉ¥ ¶·¥¤¸É ¢²¥´·¥ §Ê²ÓÉ É É·¥Ì²¥É´¨Ì¨ §³¥·¥´¨°³ £´¨É´μ£μ ³μ³¥´É ´¥°É·¨´μ (OEOE) ¶μ³μÐÓÕ¸ ¶¥±É·μ³¥É· GEMMA´ Š ²¨´¨´¸±μ°'.ˆ¸¸²¥¤Ê¥É¸Ö · ¸¸¥Ö´¨¥ ·¥ ±Éμ·´ÒÌ ´-ɨ´¥°É·¨´μ ( ¶μÉμ± 2,7 · 10 13¸³−2 ·¸− 1 )´ Ô²¥±É·μ´ Ì 1,5-±£ £¥·³ ´¨¥¢μ£μ ¤¥É¥±Éμ· , ¶μ³¥Ð¥´-μ£μ´ · ¸¸ÉμÖ´¨¨13,9 ³ μÉ Í¥´É· ±É¨¢´μ° §μ´Ò¸É ´¤ ·É´μ£μ ·¥ ±Éμ· É¥ ¶²μ¢μ°³μдμ¸ÉÓÕ 3 ƒ‚É. μ ·¥ §Ê²ÓÉ É ³¸· ¢´¥´¨Ö¸ ¶¥±É·μ¢ Ô²¥±É·μ´μ¢ μɤ Ψ,¨ §³¥·¥´´ÒÌ § (5184 + 6798)( 1853 + 1021) Î ¶·¨· ¡μÉ ÕÐ¥³¨ § £²ÊÏ¥´´μ³ ·¥ ±Éμ·¥¸μμÉ¢¥É¸É¢¥´´μ,´ 90 %-³ Ê·μ¢´¥ ¤μ-Éμ¢¥·´μ¸É¨ ¶μ²ÊÎ¥´¢¥·Ì´¨° ¶·¥¤¥² OEOE: μν < 3,2 · 10 −11 μB
Final Results of GERDA on the Two-Neutrino Double- Decay Half-Life of Ge
No full textWe present the measurement of the two-neutrino double- decay rate of
Ge performed with the GERDA Phase II experiment. With a subset of the
entire GERDA exposure, 11.8 kgyr, the half-life of the process has been
determined: yr. This is the most precise determination of the
Ge two-neutrino double- decay half-life and one of the most
precise measurements of a double- decay process. The relevant nuclear
matrix element can be extracted: Comment: 7 pages, 4 figures, 2 table
The Results of Search for the Neutrino Magnetic Moment in GEMMA Experiment
No full textThe result of the neutrino magnetic moment measurement at the Kalinin Nuclear Power Plant (KNPP) with GEMMA spectrometer is presented. The antineutrino-electron scattering is investigated. A high-purity germanium detector with a mass of 1.5 kg placed at a distance of 13.9 m from the 3 GWth reactor core is exposed to the antineutrino flux of 2.7×1013 1/cm2/s. The recoil electron spectra taken in 18134 and 4487 hours for the reactor ON and OFF periods are compared. The upper limit for the neutrino magnetic moment μν< 2.9×10−11μB at 90% C.L. is derived from the data processing
Flux modulations seen by the muon veto of the Gerda experiment
No full textThe GERDA experiment at LNGS of INFN is equipped with an active muon veto. The main part of the system is a water Cherenkov veto with 66 PMTs in the water tank surrounding the GERDA cryostat. The muon flux recorded by this veto shows a seasonal modulation. Two causes have been identified: (i) secondary muons from the CNGS neutrino beam (2.2%) and (ii) a temperature modulation of the atmosphere (1.4%). A mean cosmic muon rate of 1(mu)(0) = (3.477 +/- 0.002(stat) +/- 0.067(sys)) x 10(-4)/(s center dot m(2)) was found in good agreement with other experiments at LNGS. Combining the present result with those from previous experiments at LNGS the effective temperature coefficient alpha(T,LNGS) is determined to 0.93 +/- 0.03. A fit of the temperature coefficients measured at various underground sites yields a kaon to pion ratio r(k/Pi)of 0.10 +/- 0.03
Gerda phase II: Search for neutrinoless double beta decay
No full textThe GERDA (GERmanium Detector Array) experiment, located at the Laboratori Nazionali del Gran Sasso, is searching for neutrinoless double beta (0νββ) decay of 76 Ge. Since the end of 2015, in Phase II of the experiment, 35 kg of enriched high-purity germanium detectors are operated in liquid argon, that serves as cooling for the detectors as well as active shield against external radiation. The aim is a sensitivity on the 0νββ decay half-life larger than 10 26 yr with about 100 kg·yr exposure and a background level of about 10 −3 cts/(keV·kg·yr). An overview of the analysis of the data collected so far is presented with an emphasis on the background rejection techniques and their performance together with the half-life limit
Erratum: First Search for Bosonic Superweakly Interacting Massive Particles with Masses up to 1 MeV / c2 with GERDA (Physical Review Letters (2020) 125 (011801) DOI: 10.1103/PhysRevLett.125.011801)
No full textBecause of an incorrect evaluation of Eqs. (1) and (2), the upper limits on the coupling strengths gae and a'/a of pseudoscalar and vector bosonic superweakly interacting massive particles (super-WIMPs) deduced from the GERDA data (blue curves in Fig. 3) are incorrect. The corrected constraints are shown in the new Fig. 3 below. Depending on the particle mass, the correction has worsened the limits for gae by a factor between 1.8 and 1.9, and for a'/a by a factor between 3.3 and 3.6. As to the coupling strengths quoted on page 011801-5 for the mass of 150 keV / c 2 , the limit at 90% credible interval (C.I.) increases for gae from gae (Formula Presented)
Liquid argon light collection and veto modeling in GERDA Phase II
No full textThe 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 76Ge. 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
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