Probing gluon number density with electron-dijet correlations at EIC

A Van Hameren,P Kotko,K Kutak,S Sapeta,E Żarów

doi:10.1140/epjc/s10052-021-09529-3

Abstract

We propose a novel way of studying the gluon number density (the so-called Weizsäcker–Williams gluon distribution) using the planned Electron Ion Collider. Namely, with the help of the azimuthal correlations between the total transverse momentum of the dijet system and the scattered electron, we examine an interplay between the effect of the soft gluon emissions (the Sudakov form factor) and the gluon saturation effects. The kinematic cuts are chosen such that the dijet system is produced in the forward direction in the laboratory frame, which provides an upper bound on the probed longitudinal fractions of the hadron momentum carried by scattered gluons. Further cuts enable us to use the factorization formalism that directly involves the unpolarized Weizsäcker–Williams gluon distribution. We find this observable to be very sensitive to the soft gluon emission and moderately sensitive to the gluon saturation.

Highlights

High energy deep inelastic scattering (DIS) of electrons and nuclei at the future electron ion collider (EIC) [1] will provide a unique opportunity to perform detailed studies of various aspects of Quantum Chromodynamics (QCD) [2]
In this work we apply the recently formulated small-x Improved Transverse Momentum Dependent (ITMD) factorization [22,23] which generalizes the small-x transverse momentum dependent (TMD) factorization [18] to account for power corrections, so that it reduces to the ordinary kT factorization [24] when the saturation effects are neglected
In this Letter we propose to utilize the azimuthal correlations between the forward dijet system and the scattered electron at EIC as a tool to study the gluon number distribution

Summary

Introduction

High energy deep inelastic scattering (DIS) of electrons and nuclei at the future electron ion collider (EIC) [1] will provide a unique opportunity to perform detailed studies of various aspects of Quantum Chromodynamics (QCD) [2]. Work we focus on the production of at least two jets in DIS collisions Such processes are especially interesting, because, unlike inclusive processes, at high energies, they are directly sensitive to the gluon number density in hadrons, the so-called Weizsäcker–Williams transverse momentum dependent (TMD) gluon distribution [17,18]. In this work we apply the recently formulated small-x Improved Transverse Momentum Dependent (ITMD) factorization [22,23] which generalizes the small-x TMD factorization [18] to account for power corrections, so that it reduces to the ordinary kT factorization [24] when the saturation effects are neglected This framework, together with a model for the Sudakov resummation, has recently been successfully applied to shape description of dijet azimuthal angle decorrelations data in p − p and p − Pb collisions [25]. In [39] the Authors considered azimuthal electron-vector meson (or photon) correlations in exclusive diffractive production within CGC framework

Framework

Results

Conclusions