Observation of the suppressed decay Λ b 0 → pπ − μ + μ

• Published in: The journal of high energy physics Vol. 2017; no. 4; pp. 1 - 16
• Main Authors: Aaij, R., Adeva, B., Adinolfi, M., 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., Andreassi, G., Andreotti, M., Andrews, J. E., Appleby, R. B., Archilli, F., d’Argent, P., Arnau Romeu, J., Artamonov, A., Artuso, M., Aslanides, E., Auriemma, G., Baalouch, M., Babuschkin, I., Bachmann, S., Back, J. J., Badalov, A., Baesso, C., Baker, S., Baldini, W., Barlow, R. J., Barschel, C., Barsuk, S., Barter, W., Baszczyk, M., Batozskaya, V., Batsukh, B., Battista, V., Bay, A., Beaucourt, L., Beddow, J., Bedeschi, F., Bediaga, I., Bel, L. J., Bellee, V., Belloli, N., Belous, K., Belyaev, I., Ben-Haim, E., Bencivenni, G., Benson, S., Benton, J., Berezhnoy, A., Bernet, R., Bertolin, A., Betancourt, C., Betti, F., Bettler, M.-O., van Beuzekom, M., Bezshyiko, Ia, Bifani, S., Billoir, P., Bird, T., Birnkraut, A., Bitadze, A., Bizzeti, A., Blake, T., Blanc, F., Blouw, J., Blusk, S., Bocci, V., Boettcher, T., Bondar, A., Bondar, N., Bonivento, W., Bordyuzhin, I., Borgheresi, A., Borghi, S., Borisyak, M., Borsato, M., Bossu, F., Boubdir, M., Bowcock, T. J. V., Bowen, E., Bozzi, C., Braun, S., Britsch, M., Britton, T., Brodzicka, J., Buchanan, E., Burr, C., Bursche, A., Buytaert, J., Cadeddu, S.
• Format: Journal Article
• Language: English
• Published: SpringerOpen 01-04-2017
• Subjects: B physics; Branching fraction; Flavour Changing Neutral Currents; Hadron-Hadron scattering (experiments); Rare decay
• ISSN: 1029-8479; 1029-8479
• DOI: 10.1007/JHEP04(2017)029

Abstract The suppressed decay Λ b 0  → pπ − μ + μ −, excluding the J/ψ and ψ(2S) → μ + μ − resonances, is observed for the first time with a significance of 5.5 standard deviations. The analysis is performed with proton-proton collision data corresponding to an integrated luminosity of 3 fb−1 collected with the LHCb experiment. The Λ b 0  → pπ − μ + μ − branching fraction is measured relative to the Λ b 0  → J/ψ(→μ + μ −)pπ − branching fraction giving ℬ Λ b 0 → p π − μ + μ − ℬ Λ b 0 → J / ψ → μ + μ − p π − = 0.044 ± 0.012 ± 0.007 , $$ \frac{\mathrm{\mathcal{B}}\left({\Lambda}_b^0\to p{\pi}^{-}{\mu}^{+}{\mu}^{-}\right)}{\mathrm{\mathcal{B}}\left({\Lambda}_b^0\to \mathrm{J}/\psi \left(\to {\mu}^{+}{\mu}^{-}\right)p{\pi}^{-}\right)}=0.044\pm 0.012\pm 0.007, $$ where the first uncertainty is statistical and the second is systematic. This is the first observation of a b → d transition in a baryonic decay.