Evidence for the Strangeness-Changing Weak Decay Ξ_{b}^{-}→Λ_{b}^{0}π^{-}

• Published in: Physical review letters 2015-12, Vol.115 (24), p.241801-241801
• Main Authors: Aaij, R, Abellán Beteta, C, Adeva, B, Adinolfi, M, Affolder, A, Ajaltouni, Z, Akar, S, Albrecht, J, Alessio, F, Alexander, M, Ali, S, Alkhazov, G, Alvarez Cartelle, P, Alves, A A, Amato, S, Amerio, S, Amhis, Y, An, L, Anderlini, L, Anderson, J, Andreassi, G, Andreotti, M, Andrews, J E, Appleby, R B, Aquines Gutierrez, O, Archilli, F, d'Argent, P, Artamonov, A, Artuso, M, Aslanides, E, Auriemma, G, Baalouch, M, Bachmann, S, Back, J J, Badalov, A, Baesso, C, Baldini, W, Barlow, R J, Barschel, C, Barsuk, S, Barter, W, Batozskaya, V, Battista, V, Bay, A, Beaucourt, L, Beddow, J, Bedeschi, F, Bediaga, I, Bel, L J, Bellee, V, Belloli, N, Belyaev, I, Ben-Haim, E, Bencivenni, G, Benson, S, Benton, J, Berezhnoy, A, Bernet, R, Bertolin, A, Bettler, M-O, van Beuzekom, M, Bien, A, Bifani, S, Billoir, P, Bird, T, Birnkraut, A, Bizzeti, A, Blake, T, Blanc, F, Blouw, J, Blusk, S, Bocci, V, Bondar, A, Bondar, N, Bonivento, W, Borghi, S, Borisyak, M, Borsato, M, Bowcock, T J V, Bowen, E, Bozzi, C, Braun, S, Britsch, M, Britton, T, Brodzicka, J, Brook, N H, Buchanan, E, Burr, C, Bursche, A, Buytaert, J, Cadeddu, S, Calabrese, R, Calvi, M, Calvo Gomez, M, Campana, P, Campora Perez, D, Capriotti, L, Carbone, A, Carboni, G, Cardinale, R
• Format: Article
• Language: English
• ISSN: 1079-7114
• DOI: 10.1103/PhysRevLett.115.241801

Using a pp collision data sample corresponding to an integrated luminosity of 3.0  fb^{-1}, collected by the LHCb detector, we present the first search for the strangeness-changing weak decay Ξ_{b}^{-}→Λ_{b}^{0}π^{-}. No b hadron decay of this type has been seen before. A signal for this decay, corresponding to a significance of 3.2 standard deviations, is reported. The relative rate is measured to be f_{Ξ_{b}^{-}}/f_{Λ_{b}^{0}}B(Ξ_{b}^{-}→Λ_{b}^{0}π^{-})=(5.7±1.8_{-0.9}^{+0.8})×10^{-4},where f_{Ξ_{b}^{-}} and f_{Λ_{b}^{0}} are the b→Ξ_{b}^{-} and b→Λ_{b}^{0} fragmentation fractions, and B(Ξ_{b}^{-}→Λ_{b}^{0}π^{-}) is the branching fraction. Assuming f_{Ξ_{b}^{-}}/f_{Λ_{b}^{0}} is bounded between 0.1 and 0.3, the branching fraction B(Ξ_{b}^{-}→Λ_{b}^{0}π^{-}) would lie in the range from (0.57±0.21)% to (0.19±0.07)%.