Observation of B ¯ ( s ) 0 → J / ψ f 1 ( 1285 ) Decays and Measurement of the f 1 ( 1285 ) Mixing Angle

• Published in: Physical review letters 2014-03, Vol.112 (9), Article 091802
• Main Authors: Aaij, R., 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., Amerio, S., Amhis, Y., Anderlini, L., Anderson, J., Andreassen, R., Andreotti, M., Andrews, J. E., Appleby, R. B., Aquines Gutierrez, O., Archilli, F., Artamonov, A., Artuso, M., Aslanides, E., Auriemma, G., Baalouch, M., Bachmann, S., Back, J. J., Badalov, A., Baesso, C., Balagura, V., Baldini, W., Barlow, R. J., Barschel, C., Barsuk, S., Barter, W., Batozskaya, V., Bauer, Th, Bay, A., Beddow, J., Bedeschi, F., Bediaga, I., Belogurov, S., Belous, K., Belyaev, I., Ben-Haim, E., Bencivenni, G., Benson, S., Benton, J., Berezhnoy, A., Bernet, R., Bettler, M.-O., van Beuzekom, M., Bien, A., Bifani, S., Bird, T., Bizzeti, A., Bjørnstad, P. M., Blake, T., Blanc, F., Blouw, J., Blusk, S., Bocci, V., Bondar, A., Bondar, N., Bonivento, W., Borghi, S., Borgia, A., Bowcock, T. J. V., Bowen, E., Bozzi, C., Brambach, T., van den Brand, J., Bressieux, J., Brett, D., Britsch, M., Britton, T., Brook, N. H., Brown, H., Bursche, A., Busetto, G., Buytaert, J., Cadeddu, S., Calabrese, R., Callot, O., Calvi, M., Calvo Gomez, M., Camboni, A., Campana, P., Campora Perez, D., Carbone, A., Carboni, G., Cardinale, R., Cardini, A., Carranza-Mejia, H., Carson, L., Carvalho Akiba, K.
• Format: Article
• Language: English
• Subjects: High Energy Physics - Experiment; Physics
• ISSN: 0031-9007; 1079-7114
• DOI: 10.1103/PhysRevLett.112.091802

Decays of Bs and B0 mesons into J/\psi \pi +\pi -\pi +\pi - final states, produced in pp collisions at the LHC, are investigated using data corresponding to an integrated luminosity of 3/fb collected with the LHCb detector. B^0_(s) -> J\psi f_1(1285) decays are seen for the first time, and the branching fractions are measured. Using these rates, the f_1(1285) mixing angle between strange and non-strange components of its wave function in the q-qbar structure model is determined to be \pm (24.0^{+3.1+0.6}_{-2.6-0.8}) degrees. Implications on the possible tetraquark nature of the f_1(1285) are discussed.