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1. Search for Majoron-emitting modes of Xe136 double beta decay with the complete EXO-200 dataset

Author

Al Kharusi, S, Anton, G, Badhrees, I, Barbeau, PS, Beck, D, Belov, V, Bhatta, T, Breidenbach, M, Brunner, T, Cao, GF, Cen, WR, Chambers, C, Cleveland, B, Coon, M, Craycraft, A, Daniels, T, Darroch, L, Daugherty, SJ, Davis, J, Delaquis, S, Der Mesrobian-Kabakian, A, DeVoe, R, Dilling, J, Dolgolenko, A, Dolinski, MJ, Echevers, J, Fairbank, W, Fairbank, D, Farine, J, Feyzbakhsh, S, Fierlinger, P, Fudenberg, D, Gautam, P, Gornea, R, Gratta, G, Hall, C, Hansen, EV, Hoessl, J, Hufschmidt, P, Hughes, M, Iverson, A, Jamil, A, Jessiman, C, Jewell, MJ, Johnson, A, Karelin, A, Kaufman, LJ, Koffas, T, Krücken, R, Kuchenkov, A, Kumar, KS, Lan, Y, Larson, A, Lenardo, BG, Leonard, DS, Li, GS, Li, S, Li, Z, Licciardi, C, Lin, YH, MacLellan, R, McElroy, T, Michel, T, Mong, B, Moore, DC, Murray, K, Njoya, O, Nusair, O, Odian, A, Ostrovskiy, I, Perna, A, Piepke, A, Pocar, A, Retière, F, Robinson, AL, Rowson, PC, Ruddell, D, Runge, J, Schmidt, S, Sinclair, D, Skarpaas, K, Soma, AK, Stekhanov, V, Tarka, M, Thibado, S, Todd, J, Tolba, T, Totev, TI, Tsang, R, Veenstra, B, Veeraraghavan, V, Vogel, P, Vuilleumier, J-L, Wagenpfeil, M, Watkins, J, Weber, M, Wen, LJ, Wichoski, U, Wrede, G, and Wu, SX

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

A search for Majoron-emitting modes of the neutrinoless double beta decay of Xe136 is performed with the full EXO-200 dataset. This dataset consists of a total Xe136 exposure of 234.1 kg·yr, and includes data with detector upgrades that have improved the energy threshold relative to previous searches. A lower limit of T1/2Xe136>4.3×1024 yr at 90% C.L. on the half-life of the spectral index n=1 Majoron decay was obtained, a factor of 3.6 more stringent than the previous limit from EXO-200 and a factor of 1.6 more stringent than the previous best limit from KamLAND-Zen. This limit corresponds to a constraint on the Majoron-neutrino coupling constant of |geeM|

Published
2021

2. Imaging individual barium atoms in solid xenon for barium tagging in nEXO

Author

Chambers, C, Walton, T, Fairbank, D, Craycraft, A, Yahne, DR, Todd, J, Iverson, A, Fairbank, W, Alamare, A, Albert, JB, Anton, G, Arnquist, IJ, Badhrees, I, Barbeau, PS, Beck, D, Belov, V, Bhatta, T, Bourque, F, Brodsky, JP, Brown, E, Brunner, T, Burenkov, A, Cao, GF, Cao, L, Cen, WR, Charlebois, SA, Chiu, M, Cleveland, B, Coon, M, Cree, W, Côté, M, Dalmasson, J, Daniels, T, Darroch, L, Daugherty, SJ, Daughhetee, J, Delaquis, S, Mesrobian-Kabakian, A Der, DeVoe, R, Dilling, J, Ding, YY, Dolinski, MJ, Dragone, A, Echevers, J, Fabris, L, Farine, J, Feyzbakhsh, S, Fontaine, R, Fudenberg, D, Giacomini, G, Gornea, R, Gratta, G, Hansen, EV, Heffner, M, Hoppe, EW, Hößl, J, House, A, Hufschmidt, P, Hughes, M, Ito, Y, Jamil, A, Jessiman, C, Jewell, MJ, Jiang, XS, Karelin, A, Kaufman, LJ, Kodroff, D, Koffas, T, Kravitz, S, Krücken, R, Kuchenkov, A, Kumar, KS, Lan, Y, Larson, A, Leonard, DS, Li, G, Li, S, Li, Z, Licciardi, C, Lin, YH, Lv, P, MacLellan, R, Michel, T, Mong, B, Moore, DC, Murray, K, Newby, RJ, Ning, Z, Njoya, O, Nolet, F, Nusair, O, Odgers, K, Odian, A, Oriunno, M, Orrell, JL, Ortega, GS, Ostrovskiy, I, Overman, CT, Parent, S, and Piepke, A

Subjects
physics.ins-det, nucl-ex, Nuclear and Plasma Physics, Particle and High Energy Physics, Physical Sciences, nEXO Collaboration, General Science & Technology
Abstract

The search for neutrinoless double beta decay probes the fundamentalproperties of neutrinos, including whether or not the neutrino and antineutrinoare distinct. Double beta detectors are large and expensive, so backgroundreduction is essential for extracting the highest sensitivity. Theidentification, or 'tagging', of the $^{136}$Ba daughter atom from double betadecay of $^{136}$Xe provides a technique for eliminating backgrounds in thenEXO neutrinoless double beta decay experiment. The tagging scheme studied inthis work utilizes a cryogenic probe to trap the barium atom in solid xenon,where the barium atom is tagged via fluorescence imaging in the solid xenonmatrix. Here we demonstrate imaging and counting of individual atoms of bariumin solid xenon by scanning a focused laser across a solid xenon matrixdeposited on a sapphire window. When the laser sits on an individual atom, thefluorescence persists for $\sim$30~s before dropping abruptly to the backgroundlevel, a clear confirmation of one-atom imaging. No barium fluorescencepersists following evaporation of a barium deposit to a limit of $\leq$0.16\%.This is the first time that single atoms have been imaged in solid nobleelement. It establishes the basic principle of a barium tagging technique fornEXO.

Published
2019

3. Search for nucleon decays with EXO-200

Author

Albert, JB, Anton, G, Badhrees, I, Barbeau, PS, Bayerlein, R, Beck, D, Belov, V, Breidenbach, M, Brunner, T, Cao, GF, Cen, WR, Chambers, C, Cleveland, B, Coon, M, Craycraft, A, Cree, W, Daniels, T, Danilov, M, Daugherty, SJ, Daughhetee, J, Davis, J, Delaquis, S, Der Mesrobian-Kabakian, A, DeVoe, R, Didberidze, T, Dilling, J, Dolgolenko, A, Dolinski, MJ, Fairbank, W, Farine, J, Feyzbakhsh, S, Fierlinger, P, Fudenberg, D, Gornea, R, Graham, K, Gratta, G, Hall, C, Hansen, EV, Hoessl, J, Homiller, S, Hufschmidt, P, Hughes, M, Jamil, A, Jewell, MJ, Johnson, A, Johnston, S, Karelin, A, Kaufman, LJ, Koffas, T, Kravitz, S, Krücken, R, Kuchenkov, A, Kumar, KS, Lan, Y, Leonard, DS, Li, GS, Li, S, Licciardi, C, Lin, YH, MacLellan, R, Michel, T, Mong, B, Moore, D, Murray, K, Nelson, R, Njoya, O, Odian, A, Ostrovskiy, I, Piepke, A, Pocar, A, Retière, F, Robinson, AL, Rowson, PC, Schmidt, S, Schubert, A, Sinclair, D, Soma, AK, Stekhanov, V, Tarka, M, Tolba, T, Tsang, R, Vogel, P, Vuilleumier, J-L, Wagenpfeil, M, Waite, A, Walton, T, Weber, M, Wen, LJ, Wichoski, U, Wrede, G, Yang, L, Yen, Y-R, Zeldovich, OY, Zettlemoyer, J, and Ziegler, T

Published
2018

4. Study of the wave packet treatment of neutrino oscillation at Daya Bay

Author

An, FP, Balantekin, AB, Band, HR, Bishai, M, Blyth, S, Cao, D, Cao, GF, Cao, J, Cen, WR, Chan, YL, Chang, JF, Chang, LC, Chang, Y, Chen, HS, Chen, QY, Chen, SM, Chen, YX, Chen, Y, Cheng, J-H, Cheng, J, Cheng, YP, Cheng, ZK, Cherwinka, JJ, Chu, MC, Chukanov, A, Cummings, JP, de Arcos, J, Deng, ZY, Ding, XF, Ding, YY, Diwan, MV, Dolgareva, M, Dove, J, Dwyer, DA, Edwards, WR, Gill, R, Gonchar, M, Gong, GH, Gong, H, Grassi, M, Gu, WQ, Guan, MY, Guo, L, Guo, XH, Guo, Z, Hackenburg, RW, Han, R, Hans, S, He, M, Heeger, KM, Heng, YK, Higuera, A, Hor, YK, Hsiung, YB, Hu, BZ, Hu, T, Hu, W, Huang, EC, Huang, HX, Huang, XT, Huber, P, Huo, W, Hussain, G, Jaffe, DE, Jen, KL, Jetter, S, Ji, XP, Ji, XL, Jiao, JB, Johnson, RA, Jones, D, Joshi, J, Kettell, SH, Kohn, S, Kramer, M, Kwan, KK, Kwok, MW, Kwok, T, Langford, TJ, Lau, K, Lebanowski, L, Lee, J, Lee, JHC, Lei, RT, Leitner, R, Li, C, Li, DJ, Li, F, Li, GS, Li, QJ, Li, S, Li, SC, Li, WD, Li, XN, Li, YF, Li, ZB, Liang, H, Lin, CJ, Lin, GL, and Lin, S

Subjects
hep-ex, hep-ph, Nuclear & Particles Physics, Quantum Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics
Abstract

The disappearance of reactor $\bar{\nu}_e$ observed by the Daya Bayexperiment is examined in the framework of a model in which the neutrino isdescribed by a wave packet with a relative intrinsic momentum dispersion$\sigma_\text{rel}$. Three pairs of nuclear reactors and eight antineutrinodetectors, each with good energy resolution, distributed among threeexperimental halls, supply a high-statistics sample of $\bar{\nu}_e$ acquiredat nine different baselines. This provides a unique platform to test theeffects which arise from the wave packet treatment of neutrino oscillation. Themodified survival probability formula was used to fit Daya Bay data, providingthe first experimental limits: $2.38 \cdot 10^{-17} < \sigma_{\rm rel} < 0.23$.Treating the dimensions of the reactor cores and detectors as constraints, thelimits are improved: $10^{-14} \lesssim \sigma_{\rm rel} < 0.23$, and an upperlimit of $\sigma_{\rm rel}

Published
2017

5. Measurement of electron antineutrino oscillation based on 1230 days of operation of the Daya Bay experiment

Author

An, FP, Balantekin, AB, Band, HR, Bishai, M, Blyth, S, Cao, D, Cao, GF, Cao, J, Cen, WR, Chan, YL, Chang, JF, Chang, LC, Chang, Y, Chen, HS, Chen, QY, Chen, SM, Chen, YX, Chen, Y, Cheng, J-H, Cheng, J, Cheng, YP, Cheng, ZK, Cherwinka, JJ, Chu, MC, Chukanov, A, Cummings, JP, de Arcos, J, Deng, ZY, Ding, XF, Ding, YY, Diwan, MV, Dolgareva, M, Dove, J, Dwyer, DA, Edwards, WR, Gill, R, Gonchar, M, Gong, GH, Gong, H, Grassi, M, Gu, WQ, Guan, MY, Guo, L, Guo, XH, Guo, YH, Guo, Z, Hackenburg, RW, Han, R, Hans, S, He, M, Heeger, KM, Heng, YK, Higuera, A, Hor, YK, Hsiung, YB, Hu, BZ, Hu, T, Hu, W, Huang, EC, Huang, HX, Huang, XT, Huber, P, Huo, W, Hussain, G, Jaffe, DE, Jaffke, P, Jen, KL, Jetter, S, Ji, XP, Ji, XL, Jiao, JB, Johnson, RA, Jones, D, Joshi, J, Kang, L, Kettell, SH, Kohn, S, Kramer, M, Kwan, KK, Kwok, MW, Kwok, T, Langford, TJ, Lau, K, Lebanowski, L, Lee, J, Lee, JHC, Lei, RT, Leitner, R, Leung, JKC, Li, C, Li, DJ, Li, F, Li, GS, Li, QJ, Li, S, Li, SC, Li, WD, Li, XN, Li, YF, and Li, ZB

Subjects
Nuclear and Plasma Physics, Particle and High Energy Physics, Physical Sciences, Affordable and Clean Energy, hep-ex, nucl-ex, physics.ins-det
Abstract

A measurement of electron antineutrino oscillation by the Daya Bay Reactor Neutrino Experiment is described in detail. Six 2.9-GWth nuclear power reactors of the Daya Bay and Ling Ao nuclear power facilities served as intense sources of νe's. Comparison of the νe rate and energy spectrum measured by antineutrino detectors far from the nuclear reactors (∼1500-1950 m) relative to detectors near the reactors (∼350-600 m) allowed a precise measurement of νe disappearance. More than 2.5 million νe inverse beta-decay interactions were observed, based on the combination of 217 days of operation of six antineutrino detectors (December, 2011-July, 2012) with a subsequent 1013 days using the complete configuration of eight detectors (October, 2012-July, 2015). The νe rate observed at the far detectors relative to the near detectors showed a significant deficit, R=0.949±0.002(stat)±0.002(syst). The energy dependence of νe disappearance showed the distinct variation predicted by neutrino oscillation. Analysis using an approximation for the three-flavor oscillation probability yielded the flavor-mixing angle sin22θ13=0.0841±0.0027(stat)±0.0019(syst) and the effective neutrino mass-squared difference of |Δmee2|=(2.50±0.06(stat)±0.06(syst))×10-3 eV2. Analysis using the exact three-flavor probability found Δm322=(2.45±0.06(stat)±0.06(syst))×10-3 eV2 assuming the normal neutrino mass hierarchy and Δm322=(-2.56±0.06(stat)±0.06(syst))×10-3 eV2 for the inverted hierarchy.

Published
2017

6. Improved measurement of the reactor antineutrino flux and spectrum at Daya Bay

Author

An, FP, Balantekin, AB, Band, HR, Bishai, M, Blyth, S, Cao, D, Cao, GF, Cao, J, Cen, WR, Chan, YL, Chang, JF, Chang, LC, Chang, Y, Chen, HS, Chen, QY, Chen, SM, Chen, YX, Chen, Y, Cheng, J-H, Cheng, J, Cheng, YP, Cheng, ZK, Cherwinka, JJ, Chu, MC, Chukanov, A, Cummings, JP, de Arcos, J, Deng, ZY, Ding, XF, Ding, YY, Diwan, MV, Dolgareva, M, Dove, J, Dwyer, DA, Edwards, WR, Gill, R, Gonchar, M, Gong, GH, Gong, H, Grassi, M, Gu, WQ, Guan, MY, Guo, L, Guo, RP, Guo, XH, Guo, Z, Hackenburg, RW, Han, R, Hans, S, He, M, Heeger, KM, Heng, YK, Higuera, A, Hor, YK, Hsiung, YB, Hu, BZ, Hu, T, Hu, W, Huang, EC, Huang, HX, Huang, XT, Huber, P, Huo, W, Hussain, G, Jaffe, DE, Jaffke, P, Jen, KL, Jetter, S, Ji, XP, Ji, XL, Jiao, JB, Johnson, RA, Jones, D, Joshi, J, Kang, L, Kettell, SH, Kohn, S, Kramer, M, Kwan, KK, Kwok, MW, Kwok, T, Langford, TJ, Lau, K, Lebanowski, L, Lee, J, Lee, JHC, Lei, RT, Leitner, R, Li, C, Li, DJ, Li, F, Li, GS, Li, QJ, Li, S, Li, SC, Li, WD, Li, XN, Li, YF, Li, ZB, and Liang, H

Subjects
Nuclear and Plasma Physics, Particle and High Energy Physics, Synchrotrons and Accelerators, Physical Sciences, antineutrino flux, energy spectrum, reactor, Daya Bay, hep-ex, nucl-ex, physics.ins-det, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Nuclear & Particles Physics, Atomic, molecular and optical physics, Particle and high energy physics
Abstract

A new measurement of the reactor antineutrino flux and energy spectrum by the Daya Bay reactor neutrino experiment is reported. The antineutrinos were generated by six 2.9 GWth nuclear reactors and detected by eight antineutrino detectors deployed in two near (560 m and 600 m flux-weighted baselines) and one far (1640 m flux-weighted baseline) underground experimental halls. With 621 days of data, more than 1.2 million inverse beta decay (IBD) candidates were detected. The IBD yield in the eight detectors was measured, and the ratio of measured to predicted flux was found to be 0.946±0.020 (0.992±0.021) for the Huber+Mueller (ILL+Vogel) model. A 2.9σ deviation was found in the measured IBD positron energy spectrum compared to the predictions. In particular, an excess of events in the region of 4-6 MeV was found in the measured spectrum, with a local significance of 4.4σ. A reactor antineutrino spectrum weighted by the IBD cross section is extracted for model-independent predictions.

Published
2017

7. Improved Search for a Light Sterile Neutrino with the Full Configuration of the Daya Bay Experiment

Author

An, FP, Balantekin, AB, Band, HR, Bishai, M, Blyth, S, Cao, D, Cao, GF, Cao, J, Cen, WR, Chan, YL, Chang, JF, Chang, LC, Chang, Y, Chen, HS, Chen, QY, Chen, SM, Chen, YX, Chen, Y, Cheng, J-H, Cheng, J, Cheng, YP, Cheng, ZK, Cherwinka, JJ, Chu, MC, Chukanov, A, Cummings, JP, de Arcos, J, Deng, ZY, Ding, XF, Ding, YY, Diwan, MV, Dolgareva, M, Dove, J, Dwyer, DA, Edwards, WR, Gill, R, Gonchar, M, Gong, GH, Gong, H, Grassi, M, Gu, WQ, Guan, MY, Guo, L, Guo, RP, Guo, XH, Guo, Z, Hackenburg, RW, Han, R, Hans, S, He, M, Heeger, KM, Heng, YK, Higuera, A, Hor, YK, Hsiung, YB, Hu, BZ, Hu, T, Hu, W, Huang, EC, Huang, HX, Huang, XT, Huber, P, Huo, W, Hussain, G, Jaffe, DE, Jaffke, P, Jen, KL, Jetter, S, Ji, XP, Ji, XL, Jiao, JB, Johnson, RA, Joshi, J, Kang, L, Kettell, SH, Kohn, S, Kramer, M, Kwan, KK, Kwok, MW, Kwok, T, Langford, TJ, Lau, K, Lebanowski, L, Lee, J, Lee, JHC, Lei, RT, Leitner, R, Leung, JKC, Li, C, Li, DJ, Li, F, Li, GS, Li, QJ, Li, S, Li, SC, Li, WD, Li, XN, Li, YF, Li, ZB, and Liang, H

Subjects
Nuclear and Plasma Physics, Particle and High Energy Physics, Physical Sciences, Affordable and Clean Energy, Daya Bay Collaboration, hep-ex, Mathematical Sciences, Engineering, General Physics, Mathematical sciences, Physical sciences
Abstract

This Letter reports an improved search for light sterile neutrino mixing in the electron antineutrino disappearance channel with the full configuration of the Daya Bay Reactor Neutrino Experiment. With an additional 404 days of data collected in eight antineutrino detectors, this search benefits from 3.6 times the statistics available to the previous publication, as well as from improvements in energy calibration and background reduction. A relative comparison of the rate and energy spectrum of reactor antineutrinos in the three experimental halls yields no evidence of sterile neutrino mixing in the 2×10^{-4}≲|Δm_{41}^{2}|≲0.3  eV^{2} mass range. The resulting limits on sin^{2}2θ_{14} are improved by approx imately a factor of 2 over previous results and constitute the most stringent constraints to date in the |Δm_{41}^{2}|≲0.2  eV^{2} region.

Published
2016

8. Limits on Active to Sterile Neutrino Oscillations from Disappearance Searches in the MINOS, Daya Bay, and Bugey-3 Experiments

Author

Adamson, P, An, FP, Anghel, I, Aurisano, A, Balantekin, AB, Band, HR, Barr, G, Bishai, M, Blake, A, Blyth, S, Bock, GJ, Bogert, D, Cao, D, Cao, GF, Cao, J, Cao, SV, Carroll, TJ, Castromonte, CM, Cen, WR, Chan, YL, Chang, JF, Chang, LC, Chang, Y, Chen, HS, Chen, QY, Chen, R, Chen, SM, Chen, Y, Chen, YX, Cheng, J, Cheng, J-H, Cheng, YP, Cheng, ZK, Cherwinka, JJ, Childress, S, Chu, MC, Chukanov, A, Coelho, JAB, Corwin, L, Cronin-Hennessy, D, Cummings, JP, de Arcos, J, De Rijck, S, Deng, ZY, Devan, AV, Devenish, NE, Ding, XF, Ding, YY, Diwan, MV, Dolgareva, M, Dove, J, Dwyer, DA, Edwards, WR, Escobar, CO, Evans, JJ, Falk, E, Feldman, GJ, Flanagan, W, Frohne, MV, Gabrielyan, M, Gallagher, HR, Germani, S, Gill, R, Gomes, RA, Gonchar, M, Gong, GH, Gong, H, Goodman, MC, Gouffon, P, Graf, N, Gran, R, Grassi, M, Grzelak, K, Gu, WQ, Guan, MY, Guo, L, Guo, RP, Guo, XH, Guo, Z, Habig, A, Hackenburg, RW, Hahn, SR, Han, R, Hans, S, Hartnell, J, Hatcher, R, He, M, Heeger, KM, Heng, YK, Higuera, A, Holin, A, Hor, YK, Hsiung, YB, Hu, BZ, Hu, T, Hu, W, Huang, EC, Huang, HX, Huang, J, and Huang, XT

Subjects
Nuclear and Plasma Physics, Particle and High Energy Physics, Physical Sciences, Daya Bay Collaboration, MINOS Collaboration, hep-ex, Mathematical Sciences, Engineering, General Physics, Mathematical sciences, Physical sciences
Abstract

Searches for a light sterile neutrino have been performed independently by the MINOS and the Daya Bay experiments using the muon (anti)neutrino and electron antineutrino disappearance channels, respectively. In this Letter, results from both experiments are combined with those from the Bugey-3 reactor neutrino experiment to constrain oscillations into light sterile neutrinos. The three experiments are sensitive to complementary regions of parameter space, enabling the combined analysis to probe regions allowed by the Liquid Scintillator Neutrino Detector (LSND) and MiniBooNE experiments in a minimally extended four-neutrino flavor framework. Stringent limits on sin^{2}2θ_{μe} are set over 6 orders of magnitude in the sterile mass-squared splitting Δm_{41}^{2}. The sterile-neutrino mixing phase space allowed by the LSND and MiniBooNE experiments is excluded for Δm_{41}^{2}

Published
2016

9. New measurement of θ13 via neutron capture on hydrogen at Daya Bay

Author

An, FP, Balantekin, AB, Band, HR, Bishai, M, Blyth, S, Cao, D, Cao, GF, Cao, J, Cen, WR, Chan, YL, Chang, JF, Chang, LC, Chang, Y, Chen, HS, Chen, QY, Chen, SM, Chen, YX, Chen, Y, Cheng, JH, Cheng, J, Cheng, YP, Cheng, ZK, Cherwinka, JJ, Chu, MC, Chukanov, A, Cummings, JP, De Arcos, J, Deng, ZY, Ding, XF, Ding, YY, Diwan, MV, Dolgareva, M, Dove, J, Dwyer, DA, Edwards, WR, Gill, R, Gonchar, M, Gong, GH, Gong, H, Grassi, M, Gu, WQ, Guan, MY, Guo, L, Guo, RP, Guo, XH, Guo, Z, Hackenburg, RW, Han, R, Hans, S, He, M, Heeger, KM, Heng, YK, Higuera, A, Hor, YK, Hsiung, YB, Hu, BZ, Hu, T, Hu, W, Huang, EC, Huang, HX, Huang, XT, Huber, P, Huo, W, Hussain, G, Jaffe, DE, Jaffke, P, Jen, KL, Jetter, S, Ji, XP, Ji, XL, Jiao, JB, Johnson, RA, Joshi, J, Kang, L, Kettell, SH, Kohn, S, Kramer, M, Kwan, KK, Kwok, MW, Kwok, T, Langford, TJ, Lau, K, Lebanowski, L, Lee, J, Lee, JHC, Lei, RT, Leitner, R, Leung, JKC, Li, C, Li, DJ, Li, F, Li, GS, Li, QJ, Li, S, Li, SC, Li, WD, Li, XN, Li, YF, and Li, ZB

Subjects
hep-ex, physics.ins-det
Abstract

This article reports an improved independent measurement of neutrino mixing angle θ13 at the Daya Bay Reactor Neutrino Experiment. Electron antineutrinos were identified by inverse β-decays with the emitted neutron captured by hydrogen, yielding a data set with principally distinct uncertainties from that with neutrons captured by gadolinium. With the final two of eight antineutrino detectors installed, this study used 621 days of data including the previously reported 217-day data set with six detectors. The dominant statistical uncertainty was reduced by 49%. Intensive studies of the cosmogenic muon-induced Li9 and fast neutron backgrounds and the neutron-capture energy selection efficiency, resulted in a reduction of the systematic uncertainty by 26%. The deficit in the detected number of antineutrinos at the far detectors relative to the expected number based on the near detectors yielded sin22θ13=0.071±0.011 in the three-neutrino-oscillation framework. The combination of this result with the gadolinium-capture result is also reported.

Published
2016

10. The detector system of the Daya Bay reactor neutrino experiment

Author

An, FP, Bai, JZ, Balantekin, AB, Band, HR, Beavis, D, Beriguete, W, Bishai, M, Blyth, S, Brown, RL, Butorov, I, Cao, D, Cao, GF, Cao, J, Carr, R, Cen, WR, Chan, WT, Chan, YL, Chang, JF, Chang, LC, Chang, Y, Chasman, C, Chen, HY, Chen, HS, Chen, MJ, Chen, QY, Chen, SJ, Chen, SM, Chen, XC, Chen, XH, Chen, XS, Chen, YX, Chen, Y, Cheng, JH, Cheng, J, Cheng, YP, Cherwinka, JJ, Chidzik, S, Chow, K, Chu, MC, Cummings, JP, de Arcos, J, Deng, ZY, Ding, XF, Ding, YY, Diwan, MV, Dong, L, Dove, J, Draeger, E, Du, XF, Dwyer, DA, Edwards, WR, Ely, SR, Fang, SD, Fu, JY, Fu, ZW, Ge, LQ, Ghazikhanian, V, Gill, R, Goett, J, Gonchar, M, Gong, GH, Gong, H, Gornushkin, YA, Grassi, M, Greenler, LS, Gu, WQ, Guan, MY, Guo, RP, Guo, XH, Hackenburg, RW, Hahn, RL, Han, R, Hans, S, He, M, He, Q, He, WS, Heeger, KM, Heng, YK, Higuera, A, Hinrichs, P, Ho, TH, Hoff, M, Hor, YK, Hsiung, YB, Hu, BZ, Hu, LM, Hu, LJ, Hu, T, Hu, W, Huang, EC, Huang, HZ, Huang, HX, Huang, PW, Huang, X, Huang, XT, Huber, P, Hussain, G, Isvan, Z, Jaffe, DE, and Jaffke, P

Subjects
Nuclear and Plasma Physics, Particle and High Energy Physics, Synchrotrons and Accelerators, Physical Sciences, Neutrino oscillation, Neutrino mixing, Reactor, Daya Bay, physics.ins-det, hep-ex, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Other Physical Sciences, Nuclear & Particles Physics, Nuclear and plasma physics
Abstract

The Daya Bay experiment was the first to report simultaneous measurements of reactor antineutrinos at multiple baselines leading to the discovery of ν¯e oscillations over km-baselines. Subsequent data has provided the world's most precise measurement of sin22θ13 and the effective mass splitting Δmee2. The experiment is located in Daya Bay, China where the cluster of six nuclear reactors is among the world's most prolific sources of electron antineutrinos. Multiple antineutrino detectors are deployed in three underground water pools at different distances from the reactor cores to search for deviations in the antineutrino rate and energy spectrum due to neutrino mixing. Instrumented with photomultiplier tubes, the water pools serve as shielding against natural radioactivity from the surrounding rock and provide efficient muon tagging. Arrays of resistive plate chambers over the top of each pool provide additional muon detection. The antineutrino detectors were specifically designed for measurements of the antineutrino flux with minimal systematic uncertainty. Relative detector efficiencies between the near and far detectors are known to better than 0.2%. With the unblinding of the final two detectors' baselines and target masses, a complete description and comparison of the eight antineutrino detectors can now be presented. This paper describes the Daya Bay detector systems, consisting of eight antineutrino detectors in three instrumented water pools in three underground halls, and their operation through the first year of eight detector data-taking.

Published
2016

11. Measurement of the Reactor Antineutrino Flux and Spectrum at Daya Bay

Author

An, FP, Balantekin, AB, Band, HR, Bishai, M, Blyth, S, Butorov, I, Cao, D, Cao, GF, Cao, J, Cen, WR, Chan, YL, Chang, JF, Chang, LC, Chang, Y, Chen, HS, Chen, QY, Chen, SM, Chen, YX, Chen, Y, Cheng, JH, Cheng, J, Cheng, YP, Cherwinka, JJ, Chu, MC, Cummings, JP, de Arcos, J, Deng, ZY, Ding, XF, Ding, YY, Diwan, MV, Dove, J, Draeger, E, Dwyer, DA, Edwards, WR, Ely, SR, Gill, R, Gonchar, M, Gong, GH, Gong, H, Grassi, M, Gu, WQ, Guan, MY, Guo, L, Guo, XH, Hackenburg, RW, Han, R, Hans, S, He, M, Heeger, KM, Heng, YK, Higuera, A, Hor, YK, Hsiung, YB, Hu, BZ, Hu, LM, Hu, LJ, Hu, T, Hu, W, Huang, EC, Huang, HX, Huang, XT, Huber, P, Hussain, G, Jaffe, DE, Jaffke, P, Jen, KL, Jetter, S, Ji, XP, Ji, XL, Jiao, JB, Johnson, RA, Kang, L, Kettell, SH, Kohn, S, Kramer, M, Kwan, KK, Kwok, MW, Kwok, T, Langford, TJ, Lau, K, Lebanowski, L, Lee, J, Lei, RT, Leitner, R, Leung, KY, Leung, JKC, Lewis, CA, Li, DJ, Li, F, Li, GS, Li, QJ, Li, SC, Li, WD, Li, XN, Li, XQ, Li, YF, Li, ZB, Liang, H, Lin, CJ, and Lin, GL

Subjects
Nuclear and Plasma Physics, Particle and High Energy Physics, Synchrotrons and Accelerators, Physical Sciences, Daya Bay Collaboration, hep-ex, nucl-ex, physics.ins-det, Mathematical Sciences, Engineering, General Physics, Mathematical sciences, Physical sciences
Abstract

This Letter reports a measurement of the flux and energy spectrum of electron antineutrinos from six 2.9 GWth nuclear reactors with six detectors deployed in two near (effective baselines 512 and 561 m) and one far (1579 m) underground experimental halls in the Daya Bay experiment. Using 217 days of data, 296 721 and 41 589 inverse β decay (IBD) candidates were detected in the near and far halls, respectively. The measured IBD yield is (1.55±0.04) ×10(-18)  cm(2) GW(-1) day(-1) or (5.92±0.14) ×10(-43)  cm(2) fission(-1). This flux measurement is consistent with previous short-baseline reactor antineutrino experiments and is 0.946±0.022 (0.991±0.023) relative to the flux predicted with the Huber-Mueller (ILL-Vogel) fissile antineutrino model. The measured IBD positron energy spectrum deviates from both spectral predictions by more than 2σ over the full energy range with a local significance of up to ∼4σ between 4-6 MeV. A reactor antineutrino spectrum of IBD reactions is extracted from the measured positron energy spectrum for model-independent predictions.

Published
2016

12. New Measurement of Antineutrino Oscillation with the Full Detector Configuration at Daya Bay

Author

An, FP, Balantekin, AB, Band, HR, Bishai, M, Blyth, S, Butorov, I, Cao, GF, Cao, J, Cen, WR, Chan, YL, Chang, JF, Chang, LC, Chang, Y, Chen, HS, Chen, QY, Chen, SM, Chen, YX, Chen, Y, Cheng, JH, Cheng, J, Cheng, YP, Cherwinka, JJ, Chu, MC, Cummings, JP, de Arcos, J, Deng, ZY, Ding, XF, Ding, YY, Diwan, MV, Draeger, E, Dwyer, DA, Edwards, WR, Ely, SR, Gill, R, Gonchar, M, Gong, GH, Gong, H, Grassi, M, Gu, WQ, Guan, MY, Guo, L, Guo, XH, Hackenburg, RW, Han, R, Hans, S, He, M, Heeger, KM, Heng, YK, Higuera, A, Hor, YK, Hsiung, YB, Hu, BZ, Hu, LM, Hu, LJ, Hu, T, Hu, W, Huang, EC, Huang, HX, Huang, XT, Huber, P, Hussain, G, Jaffe, DE, Jaffke, P, Jen, KL, Jetter, S, Ji, XP, Ji, XL, Jiao, JB, Johnson, RA, Kang, L, Kettell, SH, Kramer, M, Kwan, KK, Kwok, MW, Kwok, T, Langford, TJ, Lau, K, Lebanowski, L, Lee, J, Lei, RT, Leitner, R, Leung, KY, Leung, JKC, Lewis, CA, Li, DJ, Li, F, Li, GS, Li, QJ, Li, SC, Li, WD, Li, XN, Li, XQ, Li, YF, Li, ZB, Liang, H, Lin, CJ, Lin, GL, Lin, PY, Lin, SK, and Ling, JJ

Subjects
Daya Bay Collaboration, hep-ex, nucl-ex, physics.ins-det, Mathematical Sciences, Physical Sciences, Engineering, General Physics
Abstract

We report a new measurement of electron antineutrino disappearance using the fully constructed Daya Bay Reactor Neutrino Experiment. The final two of eight antineutrino detectors were installed in the summer of 2012. Including the 404 days of data collected from October 2012 to November 2013 resulted in a total exposure of 6.9×10^{5} GW_{th}  ton days, a 3.6 times increase over our previous results. Improvements in energy calibration limited variations between detectors to 0.2%. Removal of six ^{241}Am-^{13}C radioactive calibration sources reduced the background by a factor of 2 for the detectors in the experimental hall furthest from the reactors. Direct prediction of the antineutrino signal in the far detectors based on the measurements in the near detectors explicitly minimized the dependence of the measurement on models of reactor antineutrino emission. The uncertainties in our estimates of sin^{2}2θ_{13} and |Δm_{ee}^{2}| were halved as a result of these improvements. An analysis of the relative antineutrino rates and energy spectra between detectors gave sin^{2}2θ_{13}=0.084±0.005 and |Δm_{ee}^{2}|=(2.42±0.11)×10^{-3}  eV^{2} in the three-neutrino framework.

Published
2015

13. Search for Majoron-emitting modes of Xe 136 double beta decay with the complete EXO-200 dataset

Author

Al Kharusi, S, Al Kharusi, S, Anton, G, Badhrees, I, Barbeau, PS, Beck, D, Belov, V, Bhatta, T, Breidenbach, M, Brunner, T, Cao, GF, Cen, WR, Chambers, C, Cleveland, B, Coon, M, Craycraft, A, Daniels, T, Darroch, L, Daugherty, SJ, Davis, J, Delaquis, S, Der Mesrobian-Kabakian, A, Devoe, R, Dilling, J, Dolgolenko, A, Dolinski, MJ, Echevers, J, Fairbank, J, Fairbank, D, Farine, J, Feyzbakhsh, S, Fierlinger, P, Fudenberg, D, Gautam, P, Gornea, R, Gratta, G, Hall, C, Hansen, EV, Hoessl, J, Hufschmidt, P, Hughes, M, Iverson, A, Jamil, A, Jessiman, C, Jewell, MJ, Johnson, A, Karelin, A, Kaufman, LJ, Koffas, T, Krücken, R, Kuchenkov, A, Kumar, KS, Lan, Y, Larson, A, Lenardo, BG, Leonard, DS, Li, GS, Li, S, Li, Z, Licciardi, C, Lin, YH, MacLellan, R, McElroy, T, Michel, T, Mong, B, Moore, DC, Murray, K, Njoya, O, Nusair, O, Odian, A, Ostrovskiy, I, Perna, A, Piepke, A, Pocar, A, Retière, F, Robinson, AL, Rowson, PC, Ruddell, D, Runge, J, Schmidt, S, Sinclair, D, Skarpaas, K, Soma, AK, Stekhanov, V, Tarka, M, Thibado, S, Todd, J, Tolba, T, Totev, TI, Tsang, R, Veenstra, B, Veeraraghavan, V, Vogel, P, Vuilleumier, JL, Wagenpfeil, M, Watkins, J, Weber, M, Wen, LJ, Wichoski, U, Wrede, G, Wu, SX, Al Kharusi, S, Al Kharusi, S, Anton, G, Badhrees, I, Barbeau, PS, Beck, D, Belov, V, Bhatta, T, Breidenbach, M, Brunner, T, Cao, GF, Cen, WR, Chambers, C, Cleveland, B, Coon, M, Craycraft, A, Daniels, T, Darroch, L, Daugherty, SJ, Davis, J, Delaquis, S, Der Mesrobian-Kabakian, A, Devoe, R, Dilling, J, Dolgolenko, A, Dolinski, MJ, Echevers, J, Fairbank, J, Fairbank, D, Farine, J, Feyzbakhsh, S, Fierlinger, P, Fudenberg, D, Gautam, P, Gornea, R, Gratta, G, Hall, C, Hansen, EV, Hoessl, J, Hufschmidt, P, Hughes, M, Iverson, A, Jamil, A, Jessiman, C, Jewell, MJ, Johnson, A, Karelin, A, Kaufman, LJ, Koffas, T, Krücken, R, Kuchenkov, A, Kumar, KS, Lan, Y, Larson, A, Lenardo, BG, Leonard, DS, Li, GS, Li, S, Li, Z, Licciardi, C, Lin, YH, MacLellan, R, McElroy, T, Michel, T, Mong, B, Moore, DC, Murray, K, Njoya, O, Nusair, O, Odian, A, Ostrovskiy, I, Perna, A, Piepke, A, Pocar, A, Retière, F, Robinson, AL, Rowson, PC, Ruddell, D, Runge, J, Schmidt, S, Sinclair, D, Skarpaas, K, Soma, AK, Stekhanov, V, Tarka, M, Thibado, S, Todd, J, Tolba, T, Totev, TI, Tsang, R, Veenstra, B, Veeraraghavan, V, Vogel, P, Vuilleumier, JL, Wagenpfeil, M, Watkins, J, Weber, M, Wen, LJ, Wichoski, U, Wrede, G, and Wu, SX

Abstract

A search for Majoron-emitting modes of the neutrinoless double beta decay of Xe136 is performed with the full EXO-200 dataset. This dataset consists of a total Xe136 exposure of 234.1 kg·yr, and includes data with detector upgrades that have improved the energy threshold relative to previous searches. A lower limit of T1/2Xe136>4.3×1024 yr at 90% C.L. on the half-life of the spectral index n=1 Majoron decay was obtained, a factor of 3.6 more stringent than the previous limit from EXO-200 and a factor of 1.6 more stringent than the previous best limit from KamLAND-Zen. This limit corresponds to a constraint on the Majoron-neutrino coupling constant of |geeM|<(0.4-0.9)×10-5. The lower threshold and the additional data taken resulted in a factor 8.4 improvement for the n=7 mode compared to the previous EXO-200 search. This search provides the most stringent limits to date on the Majoron-emitting decays of Xe136 with spectral indices n=1, 2, 3, and 7.

Published
2021

14. Improved measurement of the reactor antineutrino flux and spectrum at Daya Bay**Supported in part by the Ministry of Science and Technology of China, the United States Department of Energy, the Chinese Academy of Sciences, the CAS Center for Excellence in Particle Physics, the National Natural Science Foundation of China, the Guangdong provincial government, the Shenzhen municipal government, the China General Nuclear Power Group, the Research Grants Council of the Hong Kong Special Administrative Region of China, the MOST and MOE in Taiwan, the U.S. National Science Foundation, the Ministry of Education, Youth and Sports of the Czech Republic, the Joint Institute of Nuclear Research in Dubna, Russia, the NSFC-RFBR joint research program, the National Commission for Scientific and Technological Research of Chile

Author

An, FP, Balantekin, AB, Band, HR, Bishai, M, Blyth, S, Cao, D, Cao, GF, Cao, J, Cen, WR, Chan, YL, Chang, JF, Chang, LC, Chang, Y, Chen, HS, Chen, QY, Chen, SM, Chen, YX, Chen, Y, Cheng, J-H, Cheng, J, Cheng, YP, Cheng, ZK, Cherwinka, JJ, Chu, MC, Chukanov, A, Cummings, JP, de Arcos, J, Deng, ZY, Ding, XF, Ding, YY, Diwan, MV, Dolgareva, M, Dove, J, Dwyer, DA, Edwards, WR, Gill, R, Gonchar, M, Gong, GH, Gong, H, Grassi, M, Gu, WQ, Guan, MY, Guo, L, Guo, RP, Guo, XH, Guo, Z, Hackenburg, RW, Han, R, Hans, S, He, M, Heeger, KM, Heng, YK, Higuera, A, Hor, YK, Hsiung, YB, Hu, BZ, Hu, T, Hu, W, Huang, EC, Huang, HX, Huang, XT, Huber, P, Huo, W, Hussain, G, Jaffe, DE, Jaffke, P, Jen, KL, Jetter, S, Ji, XP, Ji, XL, Jiao, JB, Johnson, RA, Jones, D, Joshi, J, Kang, L, Kettell, SH, Kohn, S, Kramer, M, Kwan, KK, Kwok, MW, Kwok, T, Langford, TJ, Lau, K, Lebanowski, L, Lee, J, Lee, JHC, Lei, RT, Leitner, R, Li, C, Li, DJ, Li, F, Li, GS, Li, QJ, Li, S, Li, SC, Li, WD, Li, XN, Li, YF, Li, ZB, and Liang, H

Subjects
Particle and Plasma Physics, hep-ex, Daya Bay, energy spectrum, Molecular, Nuclear, antineutrino flux, nucl-ex, physics.ins-det, Atomic, Nuclear & Particles Physics, reactor
Abstract

A new measurement of the reactor antineutrino flux and energy spectrum by the Daya Bay reactor neutrino experiment is reported. The antineutrinos were generated by six 2.9 GWth nuclear reactors and detected by eight antineutrino detectors deployed in two near (560 m and 600 m flux-weighted baselines) and one far (1640 m flux-weighted baseline) underground experimental halls. With 621 days of data, more than 1.2 million inverse beta decay (IBD) candidates were detected. The IBD yield in the eight detectors was measured, and the ratio of measured to predicted flux was found to be 0.946±0.020 (0.992±0.021) for the Huber+Mueller (ILL+Vogel) model. A 2.9σ deviation was found in the measured IBD positron energy spectrum compared to the predictions. In particular, an excess of events in the region of 4-6 MeV was found in the measured spectrum, with a local significance of 4.4σ. A reactor antineutrino spectrum weighted by the IBD cross section is extracted for model-independent predictions.

Published
2017

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Author

An, FP, An, FP, Balantekin, AB, Band, HR, Bishai, M, Blyth, S, Cao, D, Cao, GF, Cao, J, Cen, WR, Chan, YL, Chang, JF, Chang, LC, Chang, Y, Chen, HS, Chen, QY, Chen, SM, Chen, YX, Chen, Y, Cheng, JH, Cheng, J-H, Cheng, J, Cheng, YP, Cheng, ZK, Cherwinka, JJ, Chu, MC, Chukanov, A, Cummings, JP, de Arcos, J, Deng, ZY, Ding, XF, Ding, YY, Diwan, MV, Dolgareva, M, Dove, J, Dwyer, DA, Edwards, WR, Gill, R, Gonchar, M, Gong, GH, Gong, H, Grassi, M, Gu, WQ, Guan, MY, Guo, L, Guo, RP, Guo, XH, Guo, Z, Hackenburg, RW, Han, R, Hans, S, He, M, Heeger, KM, Heng, YK, Higuera, A, Hor, YK, Hsiung, YB, Hu, BZ, Hu, T, Hu, W, Huang, EC, Huang, HX, Huang, XT, Huber, P, Huo, W, Hussain, G, Jaffe, DE, Jaffke, P, Jen, KL, Jetter, S, Ji, XP, Ji, XL, Jiao, JB, Johnson, RA, Joshi, J, Kang, L, Kettell, SH, Kohn, S, Kramer, M, Kwan, KK, Kwok, MW, Kwok, T, Langford, TJ, Lau, K, Lebanowski, L, Lee, J, Lee, JHC, Lei, RT, Leitner, R, Leung, JKC, Li, C, Li, DJ, Li, F, Li, GS, Li, QJ, Li, S, Li, SC, Li, WD, Li, XN, Li, YF, Li, ZB, An, FP, An, FP, Balantekin, AB, Band, HR, Bishai, M, Blyth, S, Cao, D, Cao, GF, Cao, J, Cen, WR, Chan, YL, Chang, JF, Chang, LC, Chang, Y, Chen, HS, Chen, QY, Chen, SM, Chen, YX, Chen, Y, Cheng, JH, Cheng, J-H, Cheng, J, Cheng, YP, Cheng, ZK, Cherwinka, JJ, Chu, MC, Chukanov, A, Cummings, JP, de Arcos, J, Deng, ZY, Ding, XF, Ding, YY, Diwan, MV, Dolgareva, M, Dove, J, Dwyer, DA, Edwards, WR, Gill, R, Gonchar, M, Gong, GH, Gong, H, Grassi, M, Gu, WQ, Guan, MY, Guo, L, Guo, RP, Guo, XH, Guo, Z, Hackenburg, RW, Han, R, Hans, S, He, M, Heeger, KM, Heng, YK, Higuera, A, Hor, YK, Hsiung, YB, Hu, BZ, Hu, T, Hu, W, Huang, EC, Huang, HX, Huang, XT, Huber, P, Huo, W, Hussain, G, Jaffe, DE, Jaffke, P, Jen, KL, Jetter, S, Ji, XP, Ji, XL, Jiao, JB, Johnson, RA, Joshi, J, Kang, L, Kettell, SH, Kohn, S, Kramer, M, Kwan, KK, Kwok, MW, Kwok, T, Langford, TJ, Lau, K, Lebanowski, L, Lee, J, Lee, JHC, Lei, RT, Leitner, R, Leung, JKC, Li, C, Li, DJ, Li, F, Li, GS, Li, QJ, Li, S, Li, SC, Li, WD, Li, XN, Li, YF, and Li, ZB

Published
2016

16. Measurement of the Spectral Shape of the β-Decay of ^{137}Xe to the Ground State of ^{137}Cs in EXO-200 and Comparison with Theory.

Author

Al Kharusi S, Anton G, Badhrees I, Barbeau PS, Beck D, Belov V, Bhatta T, Breidenbach M, Brunner T, Cao GF, Cen WR, Chambers C, Cleveland B, Coon M, Craycraft A, Daniels T, Darroch L, Daugherty SJ, Davis J, Delaquis S, Der Mesrobian-Kabakian A, DeVoe R, Dilling J, Dolgolenko A, Dolinski MJ, Echevers J, Fairbank W, Fairbank D, Farine J, Feyzbakhsh S, Fierlinger P, Fudenberg D, Gautam P, Gornea R, Gratta G, Hall C, Hansen EV, Hoessl J, Hufschmidt P, Hughes M, Iverson A, Jamil A, Jessiman C, Jewell MJ, Johnson A, Karelin A, Kaufman LJ, Koffas T, Kostensalo J, Krücken R, Kuchenkov A, Kumar KS, Lan Y, Larson A, Lenardo BG, Leonard DS, Li GS, Li S, Li Z, Licciardi C, Lin YH, MacLellan R, McElroy T, Michel T, Mong B, Moore DC, Murray K, Nakarmi P, Njoya O, Nusair O, Odian A, Ostrovskiy I, Piepke A, Pocar A, Retière F, Robinson AL, Rowson PC, Ruddell D, Runge J, Schmidt S, Sinclair D, Skarpaas K, Soma AK, Stekhanov V, Suhonen J, Tarka M, Thibado S, Todd J, Tolba T, Totev TI, Tsang R, Veenstra B, Veeraraghavan V, Vogel P, Vuilleumier JL, Wagenpfeil M, Watkins J, Weber M, Wen LJ, Wichoski U, Wrede G, Wu SX, Xia Q, Yahne DR, Yang L, Yen YR, Zeldovich OY, and Ziegler T

Abstract

We report on a comparison between the theoretically predicted and experimentally measured spectra of the first-forbidden nonunique β-decay transition ^{137}Xe(7/2^{-})→^{137}Cs(7/2^{+}). The experimental data were acquired by the EXO-200 experiment during a deployment of an AmBe neutron source. The ultralow background environment of EXO-200, together with dedicated source deployment and analysis procedures, allowed for collection of a pure sample of the decays, with an estimated signal to background ratio of more than 99 to 1 in the energy range from 1075 to 4175 keV. In addition to providing a rare and accurate measurement of the first-forbidden nonunique β-decay shape, this work constitutes a novel test of the calculated electron spectral shapes in the context of the reactor antineutrino anomaly and spectral bump.

Published
2020
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17. Search for Neutrinoless Double-β Decay with the Complete EXO-200 Dataset.

Author

Anton G, Badhrees I, Barbeau PS, Beck D, Belov V, Bhatta T, Breidenbach M, Brunner T, Cao GF, Cen WR, Chambers C, Cleveland B, Coon M, Craycraft A, Daniels T, Danilov M, Darroch L, Daugherty SJ, Davis J, Delaquis S, Der Mesrobian-Kabakian A, DeVoe R, Dilling J, Dolgolenko A, Dolinski MJ, Echevers J, Fairbank W, Fairbank D, Farine J, Feyzbakhsh S, Fierlinger P, Fudenberg D, Gautam P, Gornea R, Gratta G, Hall C, Hansen EV, Hoessl J, Hufschmidt P, Hughes M, Iverson A, Jamil A, Jessiman C, Jewell MJ, Johnson A, Karelin A, Kaufman LJ, Koffas T, Krücken R, Kuchenkov A, Kumar KS, Lan Y, Larson A, Lenardo BG, Leonard DS, Li GS, Li S, Li Z, Licciardi C, Lin YH, MacLellan R, McElroy T, Michel T, Mong B, Moore DC, Murray K, Njoya O, Nusair O, Odian A, Ostrovskiy I, Piepke A, Pocar A, Retière F, Robinson AL, Rowson PC, Ruddell D, Runge J, Schmidt S, Sinclair D, Soma AK, Stekhanov V, Tarka M, Todd J, Tolba T, Totev TI, Veenstra B, Veeraraghavan V, Vogel P, Vuilleumier JL, Wagenpfeil M, Watkins J, Weber M, Wen LJ, Wichoski U, Wrede G, Wu SX, Xia Q, Yahne DR, Yang L, Yen YR, Zeldovich OY, and Ziegler T

Abstract

A search for neutrinoless double-β decay (0νββ) in ^{136}Xe is performed with the full EXO-200 dataset using a deep neural network to discriminate between 0νββ and background events. Relative to previous analyses, the signal detection efficiency has been raised from 80.8% to 96.4±3.0%, and the energy resolution of the detector at the Q value of ^{136}Xe 0νββ has been improved from σ/E=1.23% to 1.15±0.02% with the upgraded detector. Accounting for the new data, the median 90% confidence level 0νββ half-life sensitivity for this analysis is 5.0×10^{25}  yr with a total ^{136}Xe exposure of 234.1 kg yr. No statistically significant evidence for 0νββ is observed, leading to a lower limit on the 0νββ half-life of 3.5×10^{25}  yr at the 90% confidence level.

Published
2019
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18. Search for Neutrinoless Double-Beta Decay with the Upgraded EXO-200 Detector.

Author

Albert JB, Anton G, Badhrees I, Barbeau PS, Bayerlein R, Beck D, Belov V, Breidenbach M, Brunner T, Cao GF, Cen WR, Chambers C, Cleveland B, Coon M, Craycraft A, Cree W, Daniels T, Danilov M, Daugherty SJ, Daughhetee J, Davis J, Delaquis S, Der Mesrobian-Kabakian A, DeVoe R, Didberidze T, Dilling J, Dolgolenko A, Dolinski MJ, Fairbank W, Farine J, Feyzbakhsh S, Fierlinger P, Fudenberg D, Gornea R, Graham K, Gratta G, Hall C, Hansen EV, Hoessl J, Hufschmidt P, Hughes M, Jamil A, Jewell MJ, Johnson A, Johnston S, Karelin A, Kaufman LJ, Koffas T, Kravitz S, Krücken R, Kuchenkov A, Kumar KS, Lan Y, Leonard DS, Li GS, Li S, Licciardi C, Lin YH, MacLellan R, Michel T, Mong B, Moore D, Murray K, Nelson R, Njoya O, Odian A, Ostrovskiy I, Piepke A, Pocar A, Retière F, Rowson PC, Russell JJ, Schmidt S, Schubert A, Sinclair D, Stekhanov V, Tarka M, Tolba T, Tsang R, Vogel P, Vuilleumier JL, Wagenpfeil M, Waite A, Walton T, Weber M, Wen LJ, Wichoski U, Wrede G, Yang L, Yen YR, Zeldovich OY, Zettlemoyer J, and Ziegler T

Abstract

Results from a search for neutrinoless double-beta decay (0νββ) of ^{136}Xe are presented using the first year of data taken with the upgraded EXO-200 detector. Relative to previous searches by EXO-200, the energy resolution of the detector has been improved to σ/E=1.23%, the electric field in the drift region has been raised by 50%, and a system to suppress radon in the volume between the cryostat and lead shielding has been implemented. In addition, analysis techniques that improve topological discrimination between 0νββ and background events have been developed. Incorporating these hardware and analysis improvements, the median 90% confidence level 0νββ half-life sensitivity after combining with the full data set acquired before the upgrade has increased twofold to 3.7×10^{25}  yr. No statistically significant evidence for 0νββ is observed, leading to a lower limit on the 0νββ half-life of 1.8×10^{25}  yr at the 90% confidence level.

Published
2018
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