Intrinsic charm and $D^+D^-$ asymmetry produced in proton-proton collisions

TL;DR

This paper explores how intrinsic charm in the proton influences the asymmetry in $D^+D^-$ meson production during proton-proton collisions, providing predictions for asymmetry based on different intrinsic charm probabilities.

Contribution

It introduces a method to use charm hadron-antihadron asymmetry in $pp$ collisions to establish the intrinsic charm content of the proton, considering interference effects.

Findings

Large $D^+D^-$ asymmetry at high Feynman $x$ due to intrinsic charm.

Predictions of asymmetry as a function of $x$ for various intrinsic charm probabilities.

Interference between intrinsic charm Fock state and standard PQCD contributions enhances asymmetry.

Abstract

We investigate the contribution of the charm-anticharrm ($c{\bar c}$) asymmetry of the proton eigenstate obtained from QCD lattice gauge to the asymmetry of $D^+D^-$ and $D^0{\bar D}^0$ mesons produced in $pp$ collisions at large Feynman variables $x$. It is shown that an important tool for the establishing the intrinsic charm (IC) content of the proton is the charm hadron-antihadron asymmetry formed in $pp$ collisions. Predictions for the asymmetry as function of $x$ for different IC probabilities are presented. We show that the interference of the intrinsic $|uud c{\bar c}>$ Fock state with the standard contribution from the PQCD evolution leads to a large $D^+D^-$ asymmetry at large Feynman $x$.