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

Abstract

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_1}_{C_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 0.14pm 0.32.