Bottomonia production and polarization in the NRQCD with $k_T$-factorization. II: ${\rm Y}(2S)$ and ${\chi }_b(2P)$ mesons

Abstract

The ${\rm Y}(2S)$ production and polarization at high energies is studied in the framework of $k_T$-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 ${\chi }_b(3P)$ and ${\chi }_b(2P)$ decays and contributions from ${\rm Y}(3S)$ 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 ${\rm Y}(2S)$ and ${\chi }_b(2P)$ mesons from a combined fit to ${\rm Y}(2S)$ transverse momenta distributions measured by the CMS and ATLAS Collaborations at the LHC energies $\sqrt{s}=7$ and $13$ TeV and from the relative production rate $R_{{\rm Y}(2S)}^{{\chi }_b(2P)}$ measured by the LHCb Collaboration at $\sqrt{s}=7$ and $8$ TeV. Then we apply the extracted values to investigate the polarization parameters ${\lambda }_{\theta }$, ${\lambda }_{\varphi }$ and ${\lambda }_{\theta \varphi }$, which determine the ${\rm Y}(2S)$ spin density matrix. Our predictions have a good agreement with the currently available data within the theoretical and experimental uncertainties.

21 pages, 9 figues, 2 tables

References in corpus (17)

• Heavy quarkonium: progress, puzzles, and opportunities
• J/psi (psi') production at the Tevatron and LHC at O(α_s^4v^4) in nonrelativistic QCD
• Polarization for Prompt J/psi, psi(2s) production at the Tevatron and LHC
• Upsilon production at the Tevatron and the LHC
• J/psi, psi' and Upsilon Production at Hadron Colliders: a review
• QCD radiative corrections to ${\chi }_{cJ}$ production at hadron colliders
• ${\eta }_c$ production at the LHC challenges nonrelativistic-QCD factorization
• Impact of ${\eta }_c$ hadroproduction data on charmonium production and polarization within NRQCD framework
• Charmonium Production at High Energy in the k_T-Factorization Approach
• Quarkonium production in the LHC era: a polarized perspective
• ${\eta }_c$ production at LHC and indications on the understanding of $J/\psi$ production
• QCD corrections to Upsilon production via color-octet states at the Tevatron and LHC
• Inclusive production of $J/\psi$ meson in proton-proton collisions at BNL RHIC
• Production of ${\chi }_c$- and ${\chi }_b$-mesons in high energy hadronic collisions
• Production of ${\eta }_Q$ meson at LHC
• On relation between Parton Branching Approach and CCFM evolution
• ${\chi }_{c1}$ and ${\chi }_{c2}$ polarization as a probe of color octet channel

Cited by in corpus (4)

• Revisiting the production of $J/\psi$ pairs at the LHC
• Bottomonium production and polarization in the NRQCD with $k_T$-factorization. III: ${\rm Y}(1S)$ and ${\chi }_b(1P)$ mesons
• ${\chi }_{c1}$ and ${\chi }_{c2}$ polarization as a probe of color octet channel
• Can Transverse Mass Scaling Shed Light on the Event-Activity Dependence of ${\rm Y}$ Mesons Production at LHC?