DPS in CGC: Double Quark Production and Effects of Quantum Statistics

TL;DR

This paper analyzes double quark production in high-energy p-A collisions within the CGC framework, highlighting the role of quantum statistics and the quadrupole amplitude in particle correlations.

Contribution

It explicitly demonstrates the dominance of the quadrupole amplitude in quantum statistical effects for identical fermions in high-energy collisions.

Findings

Quadrupole amplitude encodes all quantum statistical effects.

Quantum statistics effects are leading contributions at large N_c.

Correlations for non-identical quarks resemble HBT effects.

Abstract

We consider forward inclusive production of two quarks in the high energy p-A collisions in the CGC formalism. We demonstrate that the production cross-section is determined by the convolution of the proton generalized double transverse momentum-dependent distribution (2GTMD) functions with two independent eikonal scattering amplitudes: the product of two dipoles and a quadrupole. We explicitly demonstrate that the quadrupole amplitude term accounts for all the (initial and final state) effects of quantum statistics for identical fermions, and the correlations due to these effects. We also demonstrate that the effects due to quantum statistics (entirely encoded in the quadrupole) are parametrically leading contributions to the correlated particle production at large $N_c$. For non-identical quarks the quadrupole term also leads to correlated production which has characteristics similar to the HBT effect.