Exclusive diffractive dijets at HERA and EIC using GTMDs

TL;DR

This paper calculates diffractive dijet production distributions at HERA and EIC using GTMDs, compares with experimental data, and discusses the limitations of current models in matching observed cross sections.

Contribution

It introduces calculations of exclusive diffractive dijet production using off-diagonal gluon distributions (GTMDs) and compares these with experimental data, highlighting discrepancies.

Findings

Most calculated cross sections are below HERA data points.

Azimuthal correlations can be influenced by jet transverse momentum cuts.

Current models do not fully account for measured diffractive dijet cross sections.

Abstract

We calculate differential distributions for diffractive production of dijets in $ep\rightarrow e^{'}p\,jet\,jet$ reaction using off diagonal unintegrated gluon distributions, often called GTMDs for brevity. Different models are used. We focus on the contribution to exclusive $q\bar{q}$ dijets. The results of our calculations are compared with the H1 and ZEUS data. Except of one GTMD, our results are below the HERA data points. This is in contrast with recent results where the normalization was adjusted to some selected distributions and no agreement with other observables was checked. We conclude that the calculated cross sections are only a small part of the measured ones which probably contain also processes with pomeron remnant, reggeon exchange, etc. We present also azimuthal correlations between the sum and the difference of dijet transverse momenta. The cuts on transverse momenta of jets generate azimuthal correlations (in this angle) which can be easily misinterpreted as due to so-called elliptic GTMD.