Are there any challenges in the charmonia production and polarization at the LHC?статья
Статья опубликована в высокорейтинговом журнале
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Дата последнего поиска статьи во внешних источниках: 24 января 2020 г.
Аннотация:We analyze the inclusive prompt production of ψ′, χc, J/ψ and ηc mesons at the LHC using the kT-factorization approach. Our consideration is based on the off-shell production amplitudes for hard partonic subprocesses, nonrelativistic QCD formalism for the formation of bound states and transverse momentum dependent (or unintegrated) gluon densities in a proton derived from Catani-Ciafaloni-Fiorani-Marchesini equation. The nonperturbative color octet transitions are treated in terms of the multipole radiation theory. We extract the corresponding long-distance matrix elements from a combined fit to transverse momentum distributions measured at various LHC experiments. We make predictions for the polarization parameters λθ, λϕ, λθϕ and the frame-independent parameter λ∗ and compare them to the available ψ′ and J/ψ data. Finally, we present a universal set of parameters that provides a reasonable simultaneous description for the whole body of the LHC data (on the pT distributions, relative production rates and polarization observables) for the whole charmonium family.