ИСТИНА

The Upsilon(nS) production and polarization at high energies is studied in the framework of kt-factorization approach. Our consideration is based on the non-relativistic QCD formalism for bound states formation and off-shell production amplitudes for hard partonic subprocesses. The direct production mechanism, feed-down contributions from radiative chib(mP) and Upsilon decays are taken into account. The transverse momentum dependent gluon densities in a proton were derived from the Ciafaloni-Catani-Fiorani-Marchesini evolution equation as well as from the Kimber-Martin-Ryskin prescription. Treating the non-perturbative color octet transitions in terms of the mulitpole radiation theory, we extract the corresponding non-perturbative matrix elements for Upsilon(nS) and chib(mP) mesons from a combined fit to Upsilon(nS) transverse momenta distributions measured by the CMS and ATLAS Collaborations at the LHC energies 7 and 13 TeV and from the different relative production rates measured by the LHCb Collaboration at 7 and 8 TeV. Then we apply the extracted values to investigate the polarization parameters, which determine the Upsilon(nS) spin density matrix. Our predictions have a good agreement with the currently available data within the theoretical and experimental uncertainties.