Prompt charmonia production and polarization at LHC in the NRQCD with kt-factorization. II. chic mesonsстатья
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Дата последнего поиска статьи во внешних источниках: 28 июня 2016 г.
Аннотация:In the framework of the kT-factorization approach, the production of prompt ψ(2S) mesons in pp collisions at the LHC energies is studied. Our consideration is based on the off-shell amplitudes for hard partonic subprocesses g∗g∗→χcJ and nonrelativistic QCD formalism for bound states. The transverse-momentum-dependent (unintegrated) gluon densities in a proton were derived from the Ciafaloni-Catani-Fiorani-Marchesini evolution equation or, alternatively, were chosen in accordance with the Kimber-Martin-Ryskin prescription. Taking into account both color-singlet and color-octet contributions, we deduce the corresponding nonperturbative long-distance matrix elements from the fits to the latest ATLAS data on χc1 and χc2 transverse-momentum distributions at s√=7 TeV. We find that these distributions at small and moderate pT are formed mainly by the color-singlet components. We successfully described the data on the relative production rates σ(χc2)/σ(χc1) presented by the ATLAS, CMS, and LHCb Collaborations. We find that the fit points to unequal wave functions of χc1 and χc2 states.