Hard four-jet production in pA collisions

TL;DR

This paper proposes a method to disentangle two-parton correlations in the proton by analyzing four-jet production in proton-proton and proton-nucleus collisions, providing insights into the structure of generalized two-parton distributions.

Contribution

It introduces a combined measurement approach in p-p and p-A collisions to separate different sources of two-parton correlations, advancing understanding of 2GPDs.

Findings

Calculated contributions to four-jet cross sections in pA collisions.

Analyzed nuclear effects on parton distribution functions.

Outlined experimental strategies for probing proton correlations.

Abstract

In a suitably chosen back-to-back kinematics, four-jet production in hadronic collisions is known to be dominated by contributions from two independent partonic scattering processes, thus giving experimental access to the structure of generalized two-parton distributions 2GPDs. Here, we show that a combined measurement of the double hard four-jet cross section in proton-proton and proton-nucleus collisions will allow one to disentangle different sources of two-parton correlations in the proton, that cannot be disentangled with 4-jet measurements in proton-proton collisions alone. To this end, we analyze in detail the structure of 2GPDs in the nucleus (A), we calculate in the independent nucleon approximation all contributions to the double hard four-jet cross section in pA, and we determine corrections arising from the nuclear dependence of single parton distribution functions. We then outline an experimental strategy for determining the longitudinal two-parton correlations in the proton.