An improved limit on the neutrinoless double-electron capture of [Formula: see text]Ar with GERDA

GERDA Collaboration

doi:10.1140/epjc/s10052-023-12280-6

An improved limit on the neutrinoless double-electron capture of $^{36}$ Ar with GERDA

Eur Phys J C Part Fields. 2024;84(1):34. doi: 10.1140/epjc/s10052-023-12280-6. Epub 2024 Jan 14.

Author

GERDA Collaboration

Collaborators

GERDA Collaboration:
M Agostini¹, A Alexander¹, G R Araujo², A M Bakalyarov³, M Balata⁴, I Barabanov⁵, L Baudis², C Bauer⁶, S Belogurov^{5

7

8}, A Bettini^{9

10}, L Bezrukov⁵, V Biancacci¹¹, E Bossio¹², V Bothe⁶, V Brudanin¹³, R Brugnera^{9

10}, A Caldwell¹⁴, C Cattadori¹⁵, A Chernogorov^{7

3}, T Comellato¹², V D'Andrea^{16

17}, E V Demidova⁷, N Di Marco¹¹, E Doroshkevich⁵, F Fischer¹⁴, M Fomina¹³, A Gangapshev^{6

5}, A Garfagnini^{9

10}, C Gooch¹⁴, P Grabmayr¹⁸, V Gurentsov⁵, K Gusev^{13

3

12}, J Hakenmüller^{6

19}, S Hemmer¹⁰, W Hofmann⁶, J Huang², M Hult²⁰, L V Inzhechik^{5

21}, J Janicskó Csáthy¹², J Jochum¹⁸, M Junker⁴, V Kazalov⁵, Y Kermaïdic⁶, H Khushbakht¹⁸, T Kihm⁶, K Kilgus¹⁸, I V Kirpichnikov⁷, A Klimenko^{13

6

22}, R Kneißl¹⁴, K T Knöpfle⁶, O Kochetov¹³, V N Kornoukhov^{5

7

8}, M Korošec¹², P Krause¹², V V Kuzminov⁵, M Laubenstein⁴, M Lindner⁶, I Lippi¹⁰, A Lubashevskiy¹³, B Lubsandorzhiev⁵, G Lutter²⁰, C Macolino¹⁶, B Majorovits¹⁴, W Maneschg⁶, L Manzanillas¹⁴, G Marshall¹, M Misiaszek²³, M Morella¹¹, Y Müller², I Nemchenok^{13

22}, L Pandola²⁴, K Pelczar²⁰, L Pertoldi^{12

10}, P Piseri²⁵, A Pullia²⁵, C Ransom², L Rauscher¹⁸, M Redchuk¹⁰, S Riboldi²⁵, N Rumyantseva^{13

3}, C Sada^{9

10}, F Salamida¹⁶, S Schönert¹², J Schreiner⁶, M Schütt⁶, A-K Schütz¹⁸, O Schulz¹⁴, M Schwarz¹², B Schwingenheuer⁶, O Selivanenko⁵, E Shevchik¹³, M Shirchenko¹³, L Shtembari¹⁴, H Simgen⁶, A Smolnikov^{13

6}, D Stukov³, A A Vasenko⁷, A Veresnikova⁵, C Vignoli⁴, K von Sturm^{9

10}, T Wester²⁶, C Wiesinger¹², M Wojcik²³, E Yanovich⁵, B Zatschler²⁶, I Zhitnikov¹³, S V Zhukov³, D Zinatulina¹³, A Zschocke¹⁸, A J Zsigmond¹⁴, K Zuber²⁶, G Zuzel²³

Affiliations

¹ Department of Physics and Astronomy, University College London, London, UK.
² Physik-Institut, Universität Zürich, Zurich, Switzerland.
³ National Research Centre "Kurchatov Institute", Moscow, Russia.
⁴ INFN Laboratori Nazionali del Gran Sasso, Assergi, Italy.
⁵ Institute for Nuclear Research of the Russian Academy of Sciences, Moscow, Russia.
⁶ Max-Planck-Institut für Kernphysik, Heidelberg, Germany.
⁷ Institute for Theoretical and Experimental Physics, NRC "Kurchatov Institute", Moscow, Russia.
⁸ NRNU MEPhI, Moscow, Russia.
⁹ Dipartimento di Fisica e Astronomia, Università degli Studi di Padova, Padua, Italy.
¹⁰ INFN Padova, Padua, Italy.
¹¹ INFN Laboratori Nazionali del Gran Sasso and Gran Sasso Science Institute, Assergi, Italy.
¹² Physik Department, Technische Universität München, Munich, Germany.
¹³ Joint Institute for Nuclear Research, Dubna, Russia.
¹⁴ Max-Planck-Institut für Physik, Munich, Germany.
¹⁵ INFN Milano Bicocca, Milan, Italy.
¹⁶ INFN Laboratori Nazionali del Gran Sasso and Università degli Studi dell'Aquila, L'Aquila, Italy.
¹⁷ INFN Roma Tre, Rome, Italy.
¹⁸ Physikalisches Institut, Eberhard Karls Universität Tübingen, Tübingen, Germany.
¹⁹ Duke University, Durham, NC USA.
²⁰ European Commission, JRC-Geel, Geel, Belgium.
²¹ Moscow Institute of Physics and Technology, Moscow, Russia.
²² Dubna State University, Dubna, Russia.
²³ Institute of Physics, Jagiellonian University, Kraków, Poland.
²⁴ INFN Laboratori Nazionali del Sud, Catania, Italy.
²⁵ Dipartimento di Fisica, Università degli Studi di Milano and INFN Milano, Milan, Italy.
²⁶ Institut für Kern- und Teilchenphysik, Technische Universität Dresden, Dresden, Germany.

Abstract

The GERmanium Detector Array (Gerda) experiment operated enriched high-purity germanium detectors in a liquid argon cryostat, which contains 0.33% of $^{36}$ Ar, a candidate isotope for the two-neutrino double-electron capture (2 $ν$ ECEC) and therefore for the neutrinoless double-electron capture (0 $ν$ ECEC). If detected, this process would give evidence of lepton number violation and the Majorana nature of neutrinos. In the radiative 0 $ν$ ECEC of $^{36}$ Ar, a monochromatic photon is emitted with an energy of 429.88 keV, which may be detected by the Gerda germanium detectors. We searched for the $^{36}$ Ar 0 $ν$ ECEC with Gerda data, with a total live time of 4.34 year (3.08 year accumulated during Gerda Phase II and 1.26 year during Gerda Phase I). No signal was found and a 90% CL lower limit on the half-life of this process was established $T_{1 / 2} > 1.5 \cdot 10^{22}$ year.

Supplementary information: The online version contains supplementary material available at 10.1140/epjc/s10052-023-12280-6.