Next-generation neutrinoless double beta decay experiments aim for half-life sensitivities of ∼ 1027 yr, requiring suppressing backgrounds to < 1 count/tonne/yr. For this, any extra background rejection handle, beyond excellent energy resolution and the use of extremely radiopure materials, is of utmost importance. The NEXT experiment exploits differences in the spatial ionization patterns of double beta decay and single-electron events to discriminate signal from background. While the former display two Bragg peak dense ionization regions at the opposite ends of the track, the latter typically have only one such feature. Thus, comparing the energies at the track extremes provides an additional rejection tool. The unique combination of the topology-based background discrimination and excellent energy resolution (1% FWHM at the Q-value of the decay) is the distinguishing feature of NEXT. Previous studies demonstrated a topological background rejection factor of ∼ 5 when reconstructing electron-positron pairs in the 208Tl 1.6 MeV double escape peak (with Compton events as background), recorded in the NEXT-White demonstrator at the Laboratorio Subterráneo de Canfranc, with 72% signal efficiency. This was recently improved through the use of a deep convolutional neural network to yield a background rejection factor of ∼ 10 with 65% signal efficiency. Here, we present a new reconstruction method, based on the Richardson-Lucy deconvolution algorithm, which allows reversing the blurring induced by electron diffusion and electroluminescence light production in the NEXT TPC. The new method yields highly refined 3D images of reconstructed events, and, as a result, significantly improves the topological background discrimination. When applied to real-data 1.6 MeV e−e+ pairs, it leads to a background rejection factor of 27 at 57% signal efficiency.
F.T. Avignone, III, S.R. Elliott and J. Engel, Double beta decay, majorana neutrinos, and neutrino mass, Rev. Mod. Phys. 80 (2008) 481 [arXiv:0708.1033] [INSPIRE].
S. Davidson, E. Nardi and Y. Nir, Leptogenesis, Phys. Rept. 466 (2008) 105.
M. Blennow, E. Fernandez-Martinez, J. Lopez-Pavon and J. Menendez, Neutrinoless double beta decay in seesaw models, JHEP 07 (2010) 096 [arXiv:1005.3240] [INSPIRE].
S. Dell’Oro, S. Marcocci, M. Viel and F. Vissani, Neutrinoless double beta decay: 2015 review, Adv. High Energy Phys. 2016 (2016) 2162659 [arXiv:1601.07512] [INSPIRE].
M.J. Dolinski, A.W. Poon and W. Rodejohann, Neutrinoless double-beta decay: status and prospects, Annu. Rev. Nucl. Part. Sci. 69 (2019) 219.
GERDA collaboration, Final results of GERDA on the search for neutrinoless double-β decay, Phys. Rev. Lett. 125 (2020) 252502 [arXiv:2009.06079] [INSPIRE].
Majorana collaboration, A search for neutrinoless double-beta decay in 76Ge with 26 kg-yr of exposure from the Majorana demonstrator, Phys. Rev. C 100 (2019) 025501 [arXiv:1902.02299] [INSPIRE].
LEGEND collaboration, The Large Enriched Germanium Experiment for Neutrinoless Double beta decay (LEGEND), AIP Conf. Proc. 1894 (2017) 020027 [arXiv:1709.01980] [INSPIRE].
KamLAND-Zen collaboration, Search for Majorana neutrinos near the inverted mass hierarchy region with KamLAND-Zen, Phys. Rev. Lett. 117 (2016) 082503 [Addendum ibid. 117 (2016) 109903] [arXiv:1605.02889] [INSPIRE].
I. Shimizu and M. Chen, Double beta decay experiments with loaded liquid scintillator, Front. Phys. 7 (2019) 33.
EXO collaboration, Search for neutrinoless double-beta decay with the upgraded EXO-200 detector, Phys. Rev. Lett. 120 (2018) 072701 [arXiv:1707.08707] [INSPIRE].
nEXO collaboration, nEXO pre-conceptual design report, arXiv:1805.11142 [INSPIRE].
DARWIN collaboration, Sensitivity of the darwin observatory to the neutrinoless double beta decay of 136Xe, Eur. Phys. J. C 80 (2020) 808.
J.J. Gomez-Cadenas, Status and prospects of the NEXT experiment for neutrinoless double beta decay searches, arXiv:1906.01743 [INSPIRE].
X. Chen et al., PandaX-III: searching for neutrinoless double beta decay with high pressure 136Xe gas time projection chambers, Sci. China Phys. Mech. Astron. 60 (2017) 061011 [arXiv:1610.08883] [INSPIRE].
CUORE collaboration, Improved limit on neutrinoless double-beta decay in 130Te with CUORE, Phys. Rev. Lett. 124 (2020) 122501 [arXiv:1912.10966] [INSPIRE].
SNO+ collaboration, Current status and future prospects of the SNO+ experiment, Adv. High Energy Phys. 2016 (2016) 6194250 [arXiv:1508.05759] [INSPIRE].
CUPID collaboration, CUPID pre-CDR, arXiv:1907.09376 [INSPIRE].
CUPID collaboration, New limit for neutrinoless double-beta decay of 100Mo from the CUPID-Mo experiment, Phys. Rev. Lett. 126 (2021) 181802 [arXiv:2011.13243] [INSPIRE].
AMORE collaboration, First results from the AMoRE-Pilot neutrinoless double beta decay experiment, Eur. Phys. J. C 79 (2019) 791.
D. Nygren, High-pressure xenon gas electroluminescent TPC for 0nu beta beta-decay search, Nucl. Instrum. Meth. A 603 (2009) 337 [INSPIRE].
A. Bolotnikov and B. Ramsey, The spectroscopic properties of high-pressure xenon, Nucl. Instrum. Meth. A 396 (1997) 360.
NEXT collaboration, Energy calibration of the NEXT-White detector with 1% resolution near Qββ of 136Xe, JHEP 10 (2019) 230 [arXiv:1905.13110] [INSPIRE].
XENON collaboration, Energy resolution and linearity of XENON1T in the MeV energy range, Eur. Phys. J. C 80 (2020) 785.
R. Lüscher et al., Search for beta beta decay in Xe-136: New results from the Gotthard experiment, Phys. Lett. B 434 (1998) 407 [INSPIRE].
NEXT collaboration, The Next White (NEW) detector, 2018 JINST 13 P12010 [arXiv:1804.02409] [INSPIRE].
NEXT collaboration, Sensitivity of a tonne-scale NEXT detector for neutrinoless double beta decay searches, arXiv:2005.06467 [INSPIRE].
B.J.P. Jones, A.D. McDonald and D.R. Nygren, Single molecule fluorescence imaging as a technique for barium tagging in neutrinoless double beta decay, 2016 JINST 11 P12011 [arXiv:1609.04019] [INSPIRE].
A.D. McDonald et al., Demonstration of single barium ion sensitivity for neutrinoless double beta decay using single molecule fluorescence imaging, Phys. Rev. Lett. 120 (2018) 132504 [arXiv:1711.04782] [INSPIRE].
N. Byrnesa et al., Progress toward barium tagging in high pressure xenon gas with single molecule fluorescence imaging, J. Phys. Conf. Ser. 1312 (2019) 012001.
P. Thapa et al., Barium chemosensors with dry-phase fluorescence for neutrinoless double beta decay, Sci. Rep. 9 (2019) 15097.
I. Rivilla et al., Fluorescent bicolour sensor for low-background neutrinoless double β decay experiments, Nature 583 (2020) 48 [INSPIRE].
NEXT collaboration, Sensitivity of NEXT-100 to neutrinoless double beta decay, JHEP 05 (2016) 159 [arXiv:1511.09246] [INSPIRE].
NEXT collaboration, First proof of topological signature in the high pressure xenon gas TPC with electroluminescence amplification for the NEXT experiment, JHEP 01 (2016) 104 [arXiv:1507.05902] [INSPIRE].
NEXT collaboration, Demonstration of the event identification capabilities of the NEXT-White detector, JHEP 10 (2019) 052 [arXiv:1905.13141] [INSPIRE].
NEXT collaboration, Demonstration of background rejection using deep convolutional neural networks in the NEXT experiment, JHEP 01 (2021) 189 [arXiv:2009.10783] [INSPIRE].
W.H. Richardson, Bayesian-based iterative method of image restoration, J. Opt. Soc. Am. 62 (1972) 55.
L.B. Lucy, An iterative technique for the rectification of observed distributions, Astron. J. 79 (1974) 745 [INSPIRE].
E.D.C. Freitas et al., Secondary scintillation yield in high-pressure xenon gas for neutrinoless double beta decay (0nu beta beta) search, Phys. Lett. B 684 (2010) 205 [INSPIRE].
NEXT collaboration, Calibration of the NEXT-White detector using 83mKr decays, 2018 JINST 13 P10014 [arXiv:1804.01780] [INSPIRE].
T. Cormen et al., Introduction to algorithms, 2nd edition, McGraw-Hill Higher Eduation, U.S.A. (2001).
J. Martín-Albo, The NEXT experiment for neutrinoless double beta decay searches, Ph.D. thesis, Valencia University, IFIC, Valencia, Spain (2015).
NEXT collaboration, Electron drift properties in high pressure gaseous xenon, 2018 JINST 13 P07013 [arXiv:1804.01680] [INSPIRE].
S. van der Walt et al., scikit-image: image processing in Python, PeerJ 2 (2014) e453.
R. Felkai et al., Helium-Xenon mixtures to improve the topological signature in high pressure gas xenon TPCs, Nucl. Instrum. Meth. A 905 (2018) 82 [arXiv:1710.05600] [INSPIRE].
NEXT collaboration, Electron drift and longitudinal diffusion in high pressure xenon-helium gas mixtures, 2019 JINST 14 P08009 [arXiv:1902.05544] [INSPIRE].
NEXT collaboration, Low-diffusion Xe-He gas mixtures for rare-event detection: Electroluminescence Yield, JHEP 04 (2020) 034 [arXiv:1906.03984] [INSPIRE].
C.D.R. Azevedo et al., An homeopathic cure to pure Xenon large diffusion, 2016 JINST 11 C02007 [arXiv:1511.07189] [INSPIRE].
NEXT collaboration, Secondary scintillation yield of xenon with sub-percent levels of CO2 additive for rare-event detection, Phys. Lett. B 773 (2017) 663 [arXiv:1704.01623] [INSPIRE].
NEXT collaboration, Electroluminescence TPCs at the thermal diffusion limit, JHEP 01 (2019) 027 [arXiv:1806.05891] [INSPIRE].
NEXT collaboration, Application and performance of an ML-EM algorithm in NEXT, 2017 JINST 12 P08009 [arXiv:1705.10270] [INSPIRE].
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NEXT Co-spokesperson. (J. J. Gómez-Cadenas, D. R. Nygren)
Deceased. (J. T. White)
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The NEXT collaboration., Simón, A., Ifergan, Y. et al. Boosting background suppression in the NEXT experiment through Richardson-Lucy deconvolution. J. High Energ. Phys. 2021, 146 (2021). https://doi.org/10.1007/JHEP07(2021)146
- Dark Matter and Double Beta Decay (experiments)