https://doi.org/10.1140/epjc/s10052-020-8056-x
Regular Article - Theoretical Physics
Bottomonia production and polarization in the NRQCD with
-factorization. II:
and
mesons
1
Faculty of Physics, Lomonosov Moscow State University, Moscow, 119991, Russia
2
Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University, Moscow, 119991, Russia
3
Joint Institute for Nuclear Research, Dubna, Moscow Region, 141980, Russia
* e-mail: lipatov@theory.sinp.msu.ru
Received:
18
March
2020
Accepted:
16
May
2020
Published online:
30
May
2020
The production and polarization at high energies is studied in the framework of
-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
and
decays and contributions from
decays are taken into account. The transverse momentum dependent gluon densities in a proton were derived from the Ciafaloni–Catani–Fiorani–Marchesini evolution equation, Kimber-Martin-Ryskin prescription and Parton Branching method. Treating the non-perturbative color octet transitions in terms of the mulitpole radiation theory, we extract the corresponding non-perturbative matrix elements for
and
mesons from a combined fit to
transverse momenta distributions measured by the CMS and ATLAS Collaborations at the LHC energies
and 13 TeV and from the relative production rate
measured by the LHCb Collaboration at
and 8 TeV. Then we apply the extracted values to investigate the polarization parameters
,
and
, which determine the
spin density matrix. Our predictions have a good agreement with the currently available data within the theoretical and experimental uncertainties.
© The Author(s), 2020