Using decays to φ-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 fb−1 , collected by the LHCb experiment at centre-of-mass energies of 7 and 8 TeV. Denoting by BC ≡ B(b → CX) × B(C → φφ) the inclusive branching fraction of a b hadron to a charmonium state C that decays into a pair of φ mesons, ratios RC1 ≡ BC1 /BC2 are C2 determined as Rχc0 = 0.147 ± 0.023 ± 0.011, Rχc1 ηc(1S) ηc(1S) = 0.073 ± 0.016 ± 0.006, Rχc2 = 0.081 ± 0.013 ± 0.005, Rχc1 = 0.50 ± 0.11 ± 0.01, Rχc2 = 0.56 ± 0.10 ± 0.01 and Rηc(2S) = 0.040 ± 0.011 ± 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 χc2(2P) states are obtained as R X (3872) < 0.34, R X (3915) < 0.12 and χc1 χc0 Rχc2(2P) < 0.16. Differential cross-sections as a function χc2 of transverse momentum are measured for the ηc(1S) and χc states. The branching fraction of the decay Bs0 → φφφ is measured for the first time, B(Bs0 → φφφ) = (2.15±0.54± 0.28 ± 0.21B ) × 10−6 . Here the third uncertainty is due to the branching fraction of the decay Bs0 → φφ, which is used for normalization. No evidence for intermediate resonances is seen. A preferentially transverse φ polarization is observed. The measurements allow the determination of the ratio of the branching fractions for the ηc(1S) decays to φφ and pp as B(ηc(1S)→ φφ)/B(ηc(1S)→ pp) = 1.79 ± 0.14 ± 0.32
Aaij, R., Adeva, B., Adinolfi, M., Ajaltouni, Z., Akar, S., Albrecht, J., et al. (2017). Study of charmonium production in b -hadron decays and first evidence for the decay Bs0->φφφ. THE EUROPEAN PHYSICAL JOURNAL. C, PARTICLES AND FIELDS, 77(9) [10.1140/epjc/s10052-017-5151-8].
Study of charmonium production in b -hadron decays and first evidence for the decay Bs0->φφφ
Belloli, N.;Borgheresi, A.;Borsato, M.;Calvi, M.;Carniti, P.;Cassina, L.;Fazzini, D.;Gotti, C.
;Grillo, L.;Martinelli, M.;Matteuzzi, C.;Petruzzo, M.;
2017
Abstract
Using decays to φ-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 fb−1 , collected by the LHCb experiment at centre-of-mass energies of 7 and 8 TeV. Denoting by BC ≡ B(b → CX) × B(C → φφ) the inclusive branching fraction of a b hadron to a charmonium state C that decays into a pair of φ mesons, ratios RC1 ≡ BC1 /BC2 are C2 determined as Rχc0 = 0.147 ± 0.023 ± 0.011, Rχc1 ηc(1S) ηc(1S) = 0.073 ± 0.016 ± 0.006, Rχc2 = 0.081 ± 0.013 ± 0.005, Rχc1 = 0.50 ± 0.11 ± 0.01, Rχc2 = 0.56 ± 0.10 ± 0.01 and Rηc(2S) = 0.040 ± 0.011 ± 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 χc2(2P) states are obtained as R X (3872) < 0.34, R X (3915) < 0.12 and χc1 χc0 Rχc2(2P) < 0.16. Differential cross-sections as a function χc2 of transverse momentum are measured for the ηc(1S) and χc states. The branching fraction of the decay Bs0 → φφφ is measured for the first time, B(Bs0 → φφφ) = (2.15±0.54± 0.28 ± 0.21B ) × 10−6 . Here the third uncertainty is due to the branching fraction of the decay Bs0 → φφ, which is used for normalization. No evidence for intermediate resonances is seen. A preferentially transverse φ polarization is observed. The measurements allow the determination of the ratio of the branching fractions for the ηc(1S) decays to φφ and pp as B(ηc(1S)→ φφ)/B(ηc(1S)→ pp) = 1.79 ± 0.14 ± 0.32File | Dimensione | Formato | |
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