Journal Article

Observation of Λ_(b)⁰ → ψ(2S)pK⁻and Λ_(b)⁰ → J/ψ π⁺ π⁻ pK⁻decays and a measurement of theΛ_(b)⁰baryon mass

Blouw, J., Blusk, S., Blake, T., Britton, T., Braun, S., Barsuk, S., Alexander, M., Ajaltouni, Z., Aaij, R., Anderlini, L., Cardinale, R., Andreassi, G., Calvo Gomez, M., Burr, C., Barlow, R. J., Alkhazov, G., Battista, V., Brook, N. H., Baesso, C., Bedeschi, F., Alves Jr, A. A., Benton, J., Abellán Beteta, C., Birnkraut, A., Bonivento, W., Calabrese, R., Adeva, B., Affolder, A., Bencivenni, G., Bettler, M. -O., Buchanan, E., Bondar, N., Bifani, S., Badalov, A., Bozzi, C., Barter, W., Blanc, F., Adinolfi, M., Aslanides, E., Bowcock, T. J. V., Campora Perez, D., Borisyak, M., Andreotti, M., Betti, F., Akar, S., Albrecht, J., Capriotti, L., Billoir, P., Amhis, Y., Back, J. J., Belloli, N., Carboni, G., Bel, L. J., Belyaev, I., Carbone, A., Beaucourt, L., Bellee, V., Aquines Gutierrez, O., Baldini, W., Barschel, C., Amerio, S., Berezhnoy, A., Borgheresi, A., Bocci, V., Bowen, E., Bachmann, S., Cadeddu, S., Brodzicka, J., Artuso, M., Bernet, R., Borsato, M., An, L., Ali, S., Auriemma, G., Artamonov, A., Archilli, F., Appleby, R. B., Beddow, J., Bediaga, I., Bird, T., d'Argent, P., Calvi, M., Batozskaya, V., Borghi, S., Baalouch, M., van Beuzekom, M., Andrews

2016

Overview

The decays Λ_(b)⁰ → ψ(2S)pK⁻and Λ_(b)⁰ → J/ψ π⁺ π⁻ pK⁻are observed in a data sample corresponding to an integrated luminosity of 3fb ⁻¹ , collected in proton-proton collisions at 7 and 8TeV centre-of-mass energies by the LHCb detector. Theψ(2S)mesons are reconstructed through the decay modesψ(2S)→μ⁺μ⁻andψ(2S)→ J/ψπ⁺π⁻ . The branching fractions relative to that of Λ_(b)⁰ → J/ψ pK⁻are measured to be eqnarray* B(_(b)⁰ (2S) pK⁻) B(_(b)⁰ J/ pK⁻) & = & (20.70 0.76 0.46 0.37)10⁻2 , B(_(b)⁰ J/ ⁺ ⁻ pK⁻) B(_(b)⁰ J/ pK⁻) & = & (20.86 0.96 1.34)10⁻2 , eqnarray* where the first uncertainties are statistical, the second are systematic and the third is related to the knowledge ofJ/ψandψ(2S)branching fractions. The mass of theΛ_(b)⁰baryon is measured to be M(Λ_(b)⁰) = 5619.65 ± 0.17 ± 0.17\\mathrm{MeV}{/}{c}²,where the uncertainties are statistical and systematic.

• Publisher: Springer
• Subject: High Energy Physics - Experiment / Physics