Bottomonia production and polarization in the NRQCD with kT-factorization. I: Υ (3 S ) and χb(3 P ) mesons
Abstract
The Υ (3 S ) 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 transverse momentum dependent (TMD, or unintegrated) gluon densities in a proton were derived from the Ciafaloni-Catani-Fiorani-Marchesini (CCFM) evolution equation as well as from the Kimber-Martin-Ryskin (KMR) prescription. Treating the non-perturbative color octet transitions in terms of the multipole radiation theory and taking into account feed-down contributions from radiative χb(3 P ) decays, we extract the corresponding non-perturbative matrix elements for Υ (3 S ) and χb(3 P ) mesons from a combined fit to Υ (3 S ) transverse momenta distributions measured by the CMS and ATLAS Collaborations at the LHC energies √{s }=7 and 13 TeV and central rapidities. Then we apply the extracted values to describe the CDF and LHCb data on Υ (3 S ) production and to investigate the polarization parameters λθ, λϕ and λθ ϕ, which determine the Υ (3 S ) spin density matrix. Our predictions have a good agreement with the currently available data within the theoretical and experimental uncertainties.
- Publication:
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European Physical Journal C
- Pub Date:
- October 2019
- DOI:
- 10.1140/epjc/s10052-019-7365-4
- arXiv:
- arXiv:1909.05141
- Bibcode:
- 2019EPJC...79..830A
- Keywords:
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- High Energy Physics - Phenomenology
- E-Print:
- 28 pages, 10 figures. arXiv admin note: text overlap with arXiv:1906.07182