Diffractive dijet production in deep inelastic scattering and photon-hadron collisions in the color glass condensate

Tolga Altinoluk,Guillaume Beuf,Néstor Armesto,Amir H Rezaeian

doi:10.1016/j.physletb.2016.05.032

Abstract

We study exclusive dijet production in coherent diffractive processes in deep inelastic scattering and real (and virtual) photon-hadron ($\gamma^{(*)}$-h) collisions in the Color Glass Condensate formalism at leading order. We show that the diffractive dijet cross section is sensitive to the color-dipole orientation in the transverse plane, and is a good probe of possible correlations between the $q\bar{q}$-dipole transverse separation vector $\r$ and the dipole impact parameter $\b$. We also investigate the diffractive dijet azimuthal angle correlations and $t$-distributions in $\gamma^{(*)}$-h collisions and show that they are sensitive to gluon saturation effects in the small-$x$ region. In particular, we show that the $t$-distribution of diffractive dijet photo-production off a proton target exhibits a dip-type structure in the saturation region. This effect is similar to diffractive vector meson production. Besides, at variance with the inclusive case, the effect of saturation leads to stronger azimuthal correlations between the jets.

Highlights

Diffractive production provides a rich testing ground of many novel properties of Quantum Chromodynamics (QCD), see for example [1]
The main ingredient of the cross section for diffractive dijet deep inelastic scattering (DIS) in Eq (38) is the universal qqdipole-target amplitude N (r, b, x). It is universal since the same dipole amplitude in the fundamental representation appears in the cross sections for structure functions in DIS, exclusive diffractive vector meson production and deeply virtual Compton Scattering (DVCS)
In order to further show the sensitivity of the diffractive dijet correlations to saturation physics, we show in Fig. 2 our results obtained in the IP-Sat model with different saturation scales, one that corresponds to the saturation scale of a proton Qs extracted from a fit to the HERA data and one with an enhanced saturation scale 2Qs which roughly simulates its typical magnitude for a heavy nucleus in minimum-bias collisions [54,55,56]

Summary

Introduction

Diffractive production provides a rich testing ground of many novel properties of Quantum Chromodynamics (QCD), see for example [1]. It was shown that a factorization theorem exists for inclusive diffractive electron-proton DIS within the collinear framework [8] and, thereby, one can extract the diffractive parton densities [9,10,11]. This is in contrast to hard processes in diffractive hadron-hadron scattering (like diffractive DrellYan) where such factorization fails [12]. Diffractive jet production was later proposed to test further the collinear factorization and, to provide complementary information about the underlying dynamics of high-energy γ(∗)-h collisions [13,14,15,16,17]. It is important to consider schemes alternative to the collinear factorization where diffractive jet production can be computed

Objectives

Results

Conclusion