Improved limit on the branching fraction of the rare decay $${{K} ^0_{\mathrm { \scriptscriptstyle S}}} \rightarrow \mu ^+\mu ^-$$ KS0→μ+μ

• Published in: The European physical journal. C, Particles and fields Vol. 77; no. 10; pp. 1 - 12
• Main Authors: 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, L. An, L. Anderlini, G. Andreassi, M. Andreotti, J. E. Andrews, R. B. Appleby, F. Archilli, P. d’Argent, J. Arnau Romeu, A. Artamonov, M. Artuso, E. Aslanides, G. Auriemma, M. Baalouch, I. Babuschkin, S. Bachmann, J. J. Back, A. Badalov, C. Baesso, S. Baker, V. Balagura, W. Baldini, A. Baranov, R. J. Barlow, C. Barschel, S. Barsuk, W. Barter, F. Baryshnikov, M. Baszczyk, V. Batozskaya, V. Battista, A. Bay, L. Beaucourt, J. Beddow, F. Bedeschi, I. Bediaga, A. Beiter, L. J. Bel, V. Bellee, N. Belloli, K. Belous, I. Belyaev, E. Ben-Haim, G. Bencivenni, S. Benson, S. Beranek, A. Berezhnoy, R. Bernet, A. Bertolin, C. Betancourt, F. Betti, M.-O. Bettler, M. van Beuzekom, Ia. Bezshyiko, S. Bifani, P. Billoir, A. Birnkraut, A. Bitadze, A. Bizzeti, T. Blake, F. Blanc, J. Blouw, S. Blusk, V. Bocci, T. Boettcher, A. Bondar, N. Bondar, W. Bonivento, I. Bordyuzhin, A. Borgheresi, S. Borghi, M. Borisyak, M. Borsato, F. Bossu, M. Boubdir, T. J. V. Bowcock, E. Bowen, C. Bozzi, S. Braun, T. Britton, J. Brodzicka, E. Buchanan, C. Burr, A. Bursche, J. Buytaert
• Format: Journal Article
• Language: English
• Published: SpringerOpen 01.10.2017
• ISSN: 1434-6044; 1434-6052
• DOI: 10.1140/epjc/s10052-017-5230-x

Abstract A search for the decay $${{K} ^0_{\mathrm { \scriptscriptstyle S}}} \rightarrow \mu ^+\mu ^-$$ KS0→μ+μ- is performed, based on a data sample of proton-proton collisions corresponding to an integrated luminosity of $$3\,\text{ fb }^{-1} $$ 3fb-1 , collected by the LHCb experiment at centre-of-mass energies of 7 and 8$$\mathrm {\,TeV}$$ TeV . The observed yield is consistent with the background-only hypothesis, yielding a limit on the branching fraction of $$\mathcal{B}({{K} ^0_{\mathrm { \scriptscriptstyle S}}} \rightarrow \mu ^+\mu ^-) < 0.8~(1.0) \times 10^{-9}$$ B(KS0→μ+μ-)<0.8(1.0)×10-9 at $$90\%~(95\%)$$ 90%(95%) confidence level. This result improves the previous upper limit on the branching fraction by an order of magnitude.