Production of one and two $c \bar c$ pairs at LHC

TL;DR

This paper investigates charm quark pair production at the LHC, comparing theoretical calculations with experimental data, and explores the production of two pairs via different scattering mechanisms, revealing unexpectedly large cross sections.

Contribution

It introduces a detailed analysis of single and double charm pair production at LHC, including new predictions for double-parton scattering cross sections and comparison with experimental results.

Findings

Single $c ar c$ production matches some experimental data but shows missing strength with certain gluon distributions.

Double $c ar c$ production cross sections are surprisingly large, comparable to single pair production.

First experimental results on same-flavor $D$ meson pairs are discussed.

Abstract

We report on charm production at LHC. The production of single $c \bar c$ pairs is calculated in the $k_t$-factorization approach with different unintegrated gluon distributions. Examples of transverse momentum distributions for charmed mesons are presented and compared to recent experimental results from LHC. Some missing strength is observed for most of UGDFs. Furthermore we discuss production of two $c \bar c$ pairs within double-parton scattering (DPS) and single-parton scattering (SPS) mechanisms. Surprisingly large cross sections, comparable to single $c \bar c$ pair production are predicted. We discuss first experimental results from LHCb collaboration on production of pairs of $D$ mesons of the same flavour.