Total J/psi production cross section at the LHC

TL;DR

This paper calculates the total J/psi production cross section at the LHC using a QCD-based model, considering different collision energies and rapidity regions, highlighting large theoretical uncertainties.

Contribution

It provides a detailed evaluation of J/psi production cross sections within the Colour-Singlet Model across various LHC energies and rapidity ranges, including gluon and charm quark fusion processes.

Findings

Results are compatible with other models within large uncertainties.

Measurement of yield alone may not distinguish production mechanisms.

Rapidity distribution analysis covers central and forward detector regions.

Abstract

We evaluate the production cross section for direct J/psi integrated in P_T for various collision energies of the LHC in the QCD-based Colour-Singlet Model. We consider the LO contribution from gluon fusion as well as the one from a fusion of a gluon and a charm quark from the colliding protons. The rapidity distribution of the yield is evaluated in the central region relevant for the ATLAS and CMS detectors, as well as in the more forward region relevant for the ALICE and LHC-b detectors. The results obtained here are compatible with those of other approaches within the range of the theoretical uncertainties which are admittedly very large. This suggests that the "mere" measurements of the yield at the LHC will not help disentangle between the different possible quarkonium production mechanisms.