Measurement of the Bs0 →μ+μ- Branching Fraction and Effective Lifetime and Search for B0 →μ+μ- Decays

R. Aaij, B. Adeva, M. Adinolfi, Z. Ajaltouni, S. Akar, J. Albrecht, F. Alessio, M. Alexander, S. Ali, G. Alkhazov, P. Alvarez Cartelle, A. A. Alves, S. Amato, S. Amerio, Y. Amhis, LA Everse, L. Anderlini, G. Andreassi, M. Andreotti, J.E. AndrewsR. B. Appleby, F. Archilli, P. d'Argent, J. Arnau Romeu, A. Artamonov, M. Artuso, E. Aslanides, G. Auriemma, M. Baalouch, I. Babuschkin, S. Bachmann, K. Carvalho Akiba, V. Coco, P. N.Y. David, K. De Bruyn, M. Ferro-Luzzi, T. Ketel, J. Van Leerdam, T. Li, M. Merk, C. J.G. Onderwater, G. Raven, M. Schiller, N. Serra, B. Storaci, V. Syropoulos, J. Van Tilburg, S. Tolk, P. Tsopelas, N. Tuning, (LHCb Collaboration)

Research output: Contribution to JournalArticleAcademicpeer-review


A search for the rare decays Bs0→μ+μ- and B0→μ+μ- is performed at the LHCb experiment using data collected in pp collisions corresponding to a total integrated luminosity of 4.4 fb-1. An excess of Bs0→μ+μ- decays is observed with a significance of 7.8 standard deviations, representing the first observation of this decay in a single experiment. The branching fraction is measured to be B(Bs0→μ+μ-)=(3.0±0.6-0.2+0.3)×10-9, where the first uncertainty is statistical and the second systematic. The first measurement of the Bs0→μ+μ- effective lifetime, τ(Bs0→μ+μ-)=2.04±0.44±0.05 ps, is reported. No significant excess of B0→μ+μ- decays is found, and a 95% confidence level upper limit, B(B0→μ+μ-)<3.4×10-10, is determined. All results are in agreement with the standard model expectations.

Original languageEnglish
Article number191801
JournalPhysical Review Letters
Issue number19
Publication statusPublished - 11 May 2017


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