Search for exotic physics in double-β decays with GERDA Phase II

• Published in: Journal of cosmology and astroparticle physics 2022-12, Vol.2022 (12), p.12
• Main Authors: Agostini, M., Araujo, G., Bakalyarov, A.M., Balata, M., Barabanov, I., Bauer, C., Bettini, A., Bezrukov, L., Biancacci, V., Bossio, E., Bothe, V., Brugnera, R., Calgaro, S., Cattadori, C., Chernogorov, A., Comellato, T., D'Andrea, V., Demidova, E.V., Di Giacinto, A., Di Marco, N., Doroshkevich, E., Fischer, F., Fomina, M., Gangapshev, A., Garfagnini, A., Gooch, C., Grabmayr, P., Gurentsov, V., Gusev, K., Hakenmüller, J., Hemmer, S., Huang, J., Hult, M., Inzhechik, L.V., Jochum, J., Kazalov, V., Kermaïdic, Y., Khushbakht, H., Kilgus, K., Kirpichnikov, I.V., Klimenko, A., Knöpfle, K.T., Kochetov, O., Kornoukhov, V.N., Krause, P., Kuzminov, V.V., Laubenstein, M., Lindner, M., Lippi, I., Lubashevskiy, A., Lubsandorzhiev, B., Lutter, G., Macolino, C., Majorovits, B., Maneschg, W., Manzanillas, L., Marshall, G., Miloradovic, M., Mingazheva, R., Misiaszek, M., Morella, M., Müller, Y., Nemchenok, I., Pandola, L., Pelczar, K., Pertoldi, L., Piseri, P., Pullia, A., Rauscher, L., Redchuk, M., Riboldi, S., Rumyantseva, N., Sada, C., Salamida, F., Schreiner, J., Schütt, M., Schütz, A-K., Schwarz, M., Schwingenheuer, B., Shevchik, E., Shirchenko, M., Shtembari, L., Simgen, H., Smolnikov, A., Stukov, D., Vasenko, A.A., Vignoli, C., von Sturm, K., Wester, T., Wiesinger, C., Wojcik, M., Yanovich, E., Zatschler, B., Zhitnikov, I., Zhukov, S.V., Zinatulina, D., Zschocke, A., Zsigmond, A.J., Zuber, K., Zuzel, G.
• Format: Article
• Language: English
• Subjects: Bosons; Decay; double beta decay; Fermions; Germanium; neutrino properties; Neutrinos; particle physics - cosmology connection; Searching
• ISSN: 1475-7516; 1475-7516
• DOI: 10.1088/1475-7516/2022/12/012

A search for Beyond the Standard Model double- β decay modes of 76 Ge has been performed with data collected during the Phase II of the GERmanium Detector Array  ( Gerda ) experiment, located at the Laboratori Nazionali del Gran Sasso of INFN (Italy). Improved limits on the decays involving Majorons have been obtained, compared to previous experiments with  76 Ge, with half-life values on the order of 10 23 yr. For the first time with  76 Ge, limits on Lorentz invariance violation effects in double- β decay have been obtained. The isotropic coefficient å of (3) , which embeds Lorentz violation in double- β decay, has been constrained at the order of 10 -6 GeV. We also set the first experimental limits on the search for light exotic fermions in double- β decay, including sterile neutrinos.