Journal Article

Study of charmonium production in ${b}$-hadron decays and first evidence for the decay ${{{B}} ^0_{{s}}} \\!\\rightarrow \\phi \\phi \\phi

Blouw, J., Blusk, S., Bettler, M.-O., Blake, T., Britton, T., Appleby, R.B., Braun, S., Barsuk, S., Baszczyk, M., Alexander, M., Ajaltouni, Z., Aaij, R., Anderlini, L., Bordyuzhin, I., Andreassi, G., Burr, C., Balagura, V., Boettcher, T., Alkhazov, G., Battista, V., Baesso, C., Bedeschi, F., Belous, K., Baker, S., Birnkraut, A., Bonivento, W., Adeva, B., Baryshnikov, F., Bencivenni, G., Buchanan, E., Bondar, N., Bifani, S., Badalov, A., Bozzi, C., Barter, W., Blanc, F., Adinolfi, M., Aslanides, E., Borisyak, M., Andreotti, M., Betti, F., Akar, S., Bezshyiko, Ia, Albrecht, J., Billoir, P., Babuschkin, I., Amhis, Y., Belloli, N., Belyaev, I., Beaucourt, L., Bellee, V., Baldini, W., Barschel, C., Amerio, S., Berezhnoy, A., Borgheresi, A., Andrews, J.E., Bocci, V., Bowen, E., Bachmann, S., Brodzicka, J., Back, J.J., Artuso, M., Beiter, A., Bernet, R., Borsato, M., Alves Jr, A.A., An, L., Ali, S., Auriemma, G., Artamonov, A., Bel, L.J., Boubdir, M., Archilli, F., Beddow, J., Bediaga, I., d'Argent, P., Batozskaya, V., Borghi, S., Baranov, A., Baalouch, M., Betancourt, C., Beranek, S., van Beuzekom, M., Bossu, F., Bitadze, A., Barlow, R.J., Benson, S., Amato, S., Bur

2017

Overview

Using decays to $\\phi $ -meson pairs, the inclusive production of charmonium states in ${b} $ -hadron decays is studied with pp collision data corresponding to an integrated luminosity of $3.0 {\\,\\mathrm{fb}}^{-1} $ , collected by the LHCb experiment at centre-of-mass energies of 7 and 8 TeV. Denoting by ${\\mathcal {B}} _C \\equiv {\\mathcal {B}} ( {{b}} \\!\\rightarrow C X ) \\times {\\mathcal {B}} ( C\\!\\rightarrow \\phi \\phi )$ the inclusive branching fraction of a ${{b}} $ hadron to a charmonium state C that decays into a pair of $\\phi $ mesons, ratios $R^{C_1C_2}\\equiv {\\mathcal {B}} _{C_1} / {\\mathcal {B}} _{C_2}$ are determined as $R^{{\\upchi _{{{c}} 0}}}_{{\\eta _{{c}}} (1S)} = 0.147 \\pm 0.023 \\pm 0.011$ , $R^{{\\upchi _{{{c}} 1}}}_{{\\eta _{{c}}} (1S)} = 0.073 \\pm 0.016 \\pm 0.006$ , $R^{{\\upchi _{{{c}} 2}}}_{{\\eta _{{c}}} (1S)} = 0.081 \\pm 0.013 \\pm 0.005$ , $R^{{\\upchi _{{{c}} 1}}}_{{\\upchi _{{{c}} 0}}} = 0.50 \\pm 0.11 \\pm 0.01$ , $R^{{\\upchi _{{{c}} 2}}}_{{\\upchi _{{{c}} 0}}} = 0.56 \\pm 0.10 \\pm 0.01$ and $R^{{\\eta _{{c}}} (2S)}_{{\\eta _{{c}}} (1S)} = 0.040 \\pm 0.011 \\pm 0.004$ . Here and below the first uncertainties are statistical and the second systematic. Upper limits at 90% confidence level for the inclusive production of X(3872), X(3915) and ${\\upchi _{{{c}} 2}} (2P)$ states are obtained as $R^{X(3872){\\upchi _{{{c}} 1}}} < 0.34$ , $R^{X(3915){\\upchi _{{{c}} 0}}} < 0.12$ and $R^{{\\upchi _{{{c}} 2}} (2P)}_{{\\upchi _{{{c}} 2}}} < 0.16$ . Differential cross-sections as a function of transverse momentum are measured for the ${\\eta _{{c}}} (1S)$ and $\\chi _c$ states. The branching fraction of the decay ${{{B}} ^0_{{s}}} \\!\\rightarrow \\phi \\phi \\phi $ is measured for the first time, ${\\mathcal {B}} ( {{{B}} ^0_{{s}}} \\!\\rightarrow \\phi \\phi \\phi ) = (2.15 \\pm 0.54 \\pm 0.28 \\pm 0.21_{{\\mathcal {B}}}) \\times 10^{-6}$ . Here the third uncertainty is due to the branching fraction of the decay ${{{B}} ^0_{{s}}} \\!\\rightarrow \\phi \\phi $ , which is used for normalization. No evidence for intermediate resonances is seen. A preferentially transverse $\\phi $ polarization is observed. The measurements allow the determination of the ratio of the branching fractions for the ${\\eta _{{c}}} (1S)$ decays to $\\phi \\phi $ and ${{p}} {\\overline{{{p}}} $ as ${\\mathcal {B}} ( {\\eta _{{c}}} (1S)\\!\\rightarrow \\phi \\phi )/{\\mathcal {B}} ( {\\eta _{{c}}} (1S)\\!\\rightarrow {{p}} {\\overline{{{p}}} ) = 1.79 \\pm 0.14\\pm 0.32$ .

• Publisher: Springer Verlag (Germany)
• Subject: High Energy Physics - Experiment / Physics