1. A search for $\mu^+\to e^+\gamma$ with the first dataset of the MEG II experiment
- Author
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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., and Yudin, Yu. V.
- Subjects
High Energy Physics - Experiment - 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
- Published
- 2023