학술논문
A search for $\mu^+\to e^+\gamma$ with the first dataset of the MEG II experiment
Document Type
Working Paper
Author
MEG II collaboration; Afanaciev, K.; Baldini, A. M.; Ban, S.; Baranov, V.; Benmansour, H.; Biasotti, M.; Boca, G.; Cattaneo, P. W.; Cavoto, G.; Cei, F.; Chiappini, M.; Chiarello, G.; Corvaglia, A.; Cuna, F.; Maso, G. Dal; De Bari, A.; De Gerone, M.; Barusso, L. Ferrari; Francesconi, M.; Galli, L.; Gallucci, G.; Gatti, F.; Gerritzen, L.; Grancagnolo, F.; Grandoni, E. G.; Grassi, M.; Grigoriev, D. N.; Hildebrandt, M.; Ieki, K.; Ignatov, F.; Ikeda, F.; Iwamoto, T.; Karpov, S.; Kettle, P. -R.; Khomutov, N.; Kobayashi, S.; Kolesnikov, A.; Kravchuk, N.; Krylov, V.; Kuchinskiy, N.; Kyle, W.; Libeiro, T.; Malyshev, V.; Matsushita, A.; Meucci, M.; Mihara, S.; Molzon, W.; Mori, Toshinori; Nakao, M.; Nicolò, D.; Nishiguchi, H.; Ochi, A.; Ogawa, S.; Onda, R.; Ootani, W.; Oya, A.; Palo, D.; Panareo, M.; Papa, A.; Pettinacci, V.; Popov, A.; Renga, F.; Ritt, S.; Rossella, M.; Rozhdestvensky, A.; Schwendimann, P.; Shimada, K.; Signorelli, G.; Takahashi, M.; Tassielli, G. F.; Toyoda, K.; Uchiyama, Y.; Usami, M.; Venturini, A.; Vitali, B.; Voena, C.; Yamamoto, K.; Yanai, K.; Yonemoto, T.; Yoshida, K.; Yudin, Yu. V.
Source
Subject
Language
Abstract
The MEG II experiment, based at the Paul Scherrer Institut in Switzerland, reports the result of a search for the decay $\mu^+\to e^+\gamma$ from data taken in the first physics run in 2021. No excess of events over the expected background is observed, yielding an upper limit on the branching ratio of B($\mu^+\to e^+\gamma$) < $7.5 \times 10^{-13}$ (90% C.L.). The combination of this result and the limit obtained by MEG gives B($\mu^+\to e^+\gamma$) < $3.1 \times 10^{-13}$ (90% C.L.), which is the most stringent limit to date. A ten-fold larger sample of data is being collected during the years 2022-2023, and data-taking will continue in the coming years.
Comment: 10 pages, 6 figures. To be published in EPJC
Comment: 10 pages, 6 figures. To be published in EPJC