Prompt J/Psi production at LHC: new evidence for the kt-factorization

TL;DR

This paper investigates prompt J/Psi meson production and polarization at the LHC using the kt-factorization approach, incorporating feed-down effects and comparing predictions with experimental data from CMS, ATLAS, and LHCb.

Contribution

It provides the first comprehensive analysis of J/Psi production and polarization at 7 TeV within the kt-factorization framework, including feed-down contributions and polarization parameters.

Findings

Predictions agree with CMS, ATLAS, and LHCb data.

Polarization parameters are estimated and analyzed.

Unintegrated gluon densities are modeled using CCFM and KMR methods.

Abstract

In the framework of the kt-factorization approach, the production and polarization of prompt J/Psi mesons in pp collisions at the LHC energy 7 TeV is studied. Both the direct production mechanism as well as feed-down contributions from chic1, chic2 and psi' decays are taken into account. Our consideration is based on the color singlet model supplemented with the off-shell matrix elements for the corresponding partonic subprocesses. The unintegrated gluon densities in a proton are determined using the CCFM evolution equation as well the Kimber-Martin-Ryskin prescription. We compare our numerical predictions with the first experimental data taken by the CMS, ATLAS and LHCb collaborations. The estimation of all polarization parameters which determine J/Psi spin density matrix is performed.