Measurement of the isospin asymmetry in B → K (*)μ +μ - decays

R. Aaij, C. Abellan Beteta, A. Adametz, B. Adeva, M. Adinolfi, C. Adrover, A. Affolder, Z. Ajaltouni, J. Albrecht, F. Alessio, M. Alexander, S. Ali, G. Alkhazov, P. Alvarez Cartelle, A. A. Alves, S. Amato, Y. Amhis, J. Anderson, R. B. Appleby, O. Aquines GutierrezF. Archilli, A. Artamonov, M. Artuso, E. Aslanides, G. Auriemma, S. Bachmann, J. J. Back, V. Balagura, W. Baldini, R. J. Barlow, C. Barschel, S. Barsuk, W. Barter, A. Bates, C. Bauer, Th Bauer, A. Bay, J. Beddow, I. Bediaga, S. Belogurov, K. Belous, I. Belyaev, E. Ben-Haim, M. Benayoun, G. Bencivenni, S. Benson, J. Benton, R. Bernet, M. O. Bettler, M. Van Beuzekom, A. Bien, S. Bifani, T. Bird, A. Bizzeti, P. M. Bjørnstad, T. Blake, F. Blanc, C. Blanks, J. Blouw, S. Blusk, A. Bobrov, V. Bocci, A. Bondar, N. Bondar, W. Bonivento, S. Borghi, A. Borgia, T. J.V. Bowcock, C. Bozzi, T. Brambach, J. Van Den Brand, J. Bressieux, D. Brett, M. Britsch, T. Britton, N. H. Brook, H. Brown, A. Büchler-Germann, I. Burducea, A. Bursche, J. Buytaert, S. Cadeddu, O. Callot, M. Calvi, M. Calvo Gomez, A. Camboni, P. Campana, A. Carbone, G. Carboni

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Abstract

The isospin asymmetries of B → K (*)μ +μ - decays and the partial branching fractions of B 0 → K 0μ +μ - and B +→ K *+μ +μ - are measured as a function of the di-muon mass squared q 2 using an integrated luminosity of 1.0fb -1 collected with the LHCb detector. The B → Kμ +μ - isospin asymmetry integrated over q 2 is negative, deviating from zero with over 4 σ significance. The B → K *μ +μ - decay measurements are consistent with the Standard Model prediction of negligible isospin asymmetry. The observation of the decay B 0 → K s0μ +μ - is reported with 5.7 σ significance. Assuming that the branching fraction of B 0 → K 0μ +μ - is twice that of B 0 → K s0μ +μ -, the branching fractions of B 0 → K 0μ +μ - and B → K *+μ +μ - are found to be (0.31 +0.07-0.06) × 10 -6 and (1.16 ±0.19) × 10 -6, respectively.
Original languageEnglish
JournalJournal of High Energy Physics
DOIs
Publication statusPublished - 10 Aug 2012
Externally publishedYes

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Aaij, R., Abellan Beteta, C., Adametz, A., Adeva, B., Adinolfi, M., Adrover, C., Affolder, A., Ajaltouni, Z., Albrecht, J., Alessio, F., Alexander, M., Ali, S., Alkhazov, G., Alvarez Cartelle, P., Alves, A. A., Amato, S., Amhis, Y., Anderson, J., Appleby, R. B., ... Carboni, G. (2012). Measurement of the isospin asymmetry in B → K (*)μ +μ - decays. Journal of High Energy Physics. https://doi.org/10.1007/JHEP07(2012)133