Boosting background suppression in the NEXT experiment through Richardson-Lucy deconvolution

Journal Article · Wed Jul 21 00:00:00 EDT 2021 · Journal of High Energy Physics (Online)

DOI:https://doi.org/10.1007/jhep07(2021)146· OSTI ID:1820325

Simón, A.; Ifergan, Y.; Redwine, A. B.; Weiss-Babai, R.; Arazi, L. ; Adams, C.; Almazán, H.; Álvarez, V.; Aparicio, B.; Aranburu, A. I.; Arnquist, I. J.; Azevedo, C. R.; Bailey, K.; Ballester, F.; Benlloch-Rodríguez, J. M.; Borges, F. M.; Byrnes, N.; Cárcel, S.; Carrión, J. V.; Cebrián, S. ; Church, E.; Conde, C. N.; Contreras, T.; Cossío, F. P.; Denisenko, A. A.; Díaz, G.; Díaz, J.; Escada, J.; Esteve, R.; Felkai, R.; Fernandes, L. P.; Ferrario, P.; Ferreira, A. L.; Foss, F.; Freitas, E. C.; Freixa, Z.; Generowicz, J.; Goldschmidt, A.; Gómez-Cadenas, J. J.; González, R.; González-Díaz, D.; Gosh, S.; Guenette, R.; Gutiérrez, R. M.; Haefner, J.; Hafidi, K.; Hauptman, J.; Henriques, C. O.; Hernando Morata, J. A.; Herrero, P.; Herrero, V.; Ho, J.; Jones, B. P.; Kekic, M.; Labarga, L.; Laing, A.; Lebrun, P.; López-March, N.; Losada, M.; Mano, R. P.; Martín-Albo, J.; Martínez, A.; Martínez-Vara, M.; Martínez-Lema, G.; McDonald, A. D.; Meziani, Z. -E.; Monrabal, F.; Monteiro, C. B.; Mora, F. J.; Muñoz Vidal, J.; Newhouse, C.; Novella, P.; Nygren, D. R.; Oblak, E.; Odriozola-Gimeno, M.; Palmeiro, B.; Para, A.; Pérez, J.; Querol, M.; Renner, J.; Ripoll, L.; Rivilla, I.; Rodríguez García, Y.; Rodríguez, J.; Rogero, C.; Rogers, L.; Romeo, B.; Romo-Luque, C.; Santos, F. P.; dos Santos, J. F.; Sorel, M.; Stanford, C.; Teixeira, J. R.; Thapa, P.; Toledo, J. F.; Torrent, J.; Usón, A.; Veloso, J. A.; Vuong, T. T.; Webb, R.; White, J. T.; Woodruff, K.; Yahlali, N.

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.

• Research Organization: Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States); Pacific Northwest National Laboratory (PNNL), Richland, WA (United States); Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States); Argonne National Laboratory (ANL), Argonne, IL (United States); Univ. of Texas, Arlington, TX (United States)
• Sponsoring Organization: USDOE Office of Science (SC), High Energy Physics (HEP); National Strategic Reference Framework (NSRF); European Research Council (ERC); Fermi National Accelerator Laboratory; University of Texas – Arlington; Ben-Gurion University of the Negev; USDOE Office of Science (SC), Nuclear Physics (NP)
• Contributing Organization: The NEXT Collaboration; NEXT Collaboration
• Grant/Contract Number: AC02-05CH11231; AC02-07CH11359; AC02-06CH11357; FG02-13ER42020; SC0019223; SC0019054
• OSTI ID: 1820325
• Alternate ID(s): OSTI ID: 1824188; OSTI ID: 1864336; OSTI ID: 1908633
• Report Number(s): FERMILAB-PUB-21-114-SCD; arXiv:2102.11931; ark:/13030/qt2rd1q03b
• Journal Information: Journal of High Energy Physics (Online), Vol. 2021, Issue 7; ISSN 1029-8479
• Publisher: Springer Nature
• Country of Publication: United States
• Language: English

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