Production of $c \bar c$ pairs at LHC: $k_t$-factorization and double-parton scattering

TL;DR

This paper analyzes charm quark pair production at the LHC using $k_t$-factorization and double-parton scattering, comparing theoretical predictions with experimental data and highlighting significant DPS contributions.

Contribution

It introduces a combined analysis of single and double charm production at LHC energies using $k_t$-factorization and simple DPS models, revealing unexpectedly large DPS cross sections.

Findings

Differential distributions align with some experimental data but show missing strength.

Double-parton scattering can produce cross sections comparable to single-parton scattering.

Large DPS contributions suggest importance of multiple interactions at LHC energies.

Abstract

We discuss charm production at LHC. The production of single $c \bar c$ pairs is calculated in the $k_t$-factorization approach. We use several unintegrated gluon distributions from the literature. Differential distributions for several charmed mesons are presented and compared to recent results of the ALICE and LHCb collaborations. Some missing strength can be observed. Furthermore we discuss production of two $c \bar c$ pairs within a simple formalism of double-parton scattering (DPS). Surprisingly large cross sections, comparable to single-parton scattering (SPS) contribution to $c \bar c$ production, are predicted for LHC energies.