Digluon contribution to $J/\psi$ production

TL;DR

This paper investigates how double gluon distributions influence $J/$ production, revealing that despite theoretical suppression, they significantly affect results at LHC energies, especially at high transverse momentum.

Contribution

It introduces the role of double gluon distributions in charmonium production, highlighting their importance at small Bjorken $x_{B}$ and high $p_{T}$ in LHC conditions.

Findings

Double gluon contributions are numerically significant at LHC energies.

These contributions are not suppressed at high $J/$ transverse momentum.

Gluonic density enhancement at small $x_{B}$ amplifies the effect.

Abstract

In this paper we study the contribution of the double parton distributions of gluons to the charmonium production. Despite being suppressed in the heavy quark mass limit, numerically this contribution gives a sizeable correction to the leading order $k_{T}$ factorization result in LHC kinematics due to enhancement of gluonic densities in the small Bjorken $x_{B}$ limit. This contribution is not suppressed at large $J/\psi$ momenta $p_{T}$ and thus presents one of the complementary mechanisms of charmonia production in this kinematics.