InclusiveS-wave charmonium productions inBdecays

CPviolation in quasi-inclusiveB→K(*)Browder1, Datta2, He3 et al. 1998Phys. Rev. D311400View full textAdd to dashboardCite

“…In this approximation the color octet matrix element does not contribute because it cannot be expressed in a factorizable color singlet form. The color octet operators could contribute if, for instance, the quark pair emits or absorbs a gluon [20]. It has been shown [21] that in the leading order, where the energy of the light quark pair E ∼ m b with m b → ∞, the octet matrix element vanishes when the final state is two 0 − mesons.…”

Tevatron-hera colour-octet charmonium anomaly versus higher-order QCD effects

“…In the meantime, there have been a number of interesting proposals and encouraging results concerning possible colour-octet signatures of inclusive J/ψ production in e + e − annihilation in the continuum [5] and on the Z-boson resonance [6], hadronic collisions in the fixed-target mode [7], B-meson decays [8], and photoproduction in the forward direction [9] and at finite transverse momentum [10,11]. Although the experimental Zboson-decay data from CERN LEP [12] are in agreement with the predicted colour-octet signature, they do not exclude the hypothesis that the observed prompt charmonium signal is produced by colour-singlet processes alone.…”

Color-singlet and color-octet contributions to photoproduction

“…Color-octet matrix elements have been fitted to prompt J/ψ data from CDF 24 and found to be O(10 −2 GeV 3 ), consistent with the NRQCD velocity scaling rules. 4,5 Meanwhile, fit values for color-octet matrix elements have also been obtained from analyses of quarkonium production in hadronic collisions at fixed-target experiments 9 , J/ψ photoproduction at the elastic peak 18 and J/ψ production in B decays 10 . The results seem to indicate that the values for the color-octet matrix elements extracted from the Tevatron data at moderate p ⊥ are too large; they should however be considered with some caution since significant higher-twist corrections are expected to contribute in the small-p ⊥ region probed at fixed target experiments and in elastic J/ψ photoproduction.…”

“…Color-octet production of J/ψ particles has also been studied in the context of e + e − annihilation 6 , Z decays 7 , hadronic collisions at fixed-target experiments 8,9 and B decays 10 . Here, I review the impact of color-octet contributions and higherorder QCD corrections on the cross section for J/ψ photoproduction.…”