Probing gluon saturation via diffractive jets in ultra-peripheral nucleus-nucleus collisions

Abstract

We argue that semi-inclusive photo-production of a pair of hard jets via coherent diffraction in nucleus-nucleus ultra-peripheral collisions at high energy is a golden channel to study gluon saturation. The dominant contribution is the diffractive production of three jets in an asymmetric configuration. Two of the jets are hard and propagate at nearly central pseudo-rapidities. The third jet is semi-hard, with transverse momentum comparable to the nuclear saturation momentum, and is well separated in pseudo-rapidity from the hard dijets. The emission of the semi-hard jet allows for strong scattering, thus avoiding the "higher-twist" suppression of the exclusive dijet production due to colour transparency. We compute the trijet cross-section using the diffractive TMD factorisation which emerges from the CGC effective theory at high energy. The cross-section is controlled by gluon saturation, which leaves its imprints on the structure of the final state, notably on the rapidity distribution.

arXiv comment23 pages, 9 figures

References in corpus (20)

• Computing Quark and Gluon Distribution Functions for Very Large Nuclei
• Operator expansion for high-energy scattering
• Small-x F_2 Structure Function of a Nucleus Including Multiple Pomeron Exchanges
• Nonlinear Gluon Evolution in the Color Glass Condensate: I
• The Wilson renormalization group for low x physics: towards the high density regime
• Green's Functions in the Color Field of a Large Nucleus
• The BFKL Equation from the Wilson Renormalization Group
• Nonlinear Gluon Evolution in the Color Glass Condensate: II
• Saturation in Diffractive Deep Inelastic Scattering
• Relating different approaches to nonlinear QCD evolution at finite gluon density
• Physics of Ultra-Peripheral Nuclear Collisions
• Inclusive and Diffractive Structure Functions at Small x
• Large Rapidity Gap Events in Deep Inelastic Scattering
• Universality of multi-particle production in QCD at high energies
• Probing parton saturation and the gluon dipole via diffractive jet production at the Electron-Ion Collider
• Diffractive deeply inelastic scattering of hadronic states with small transverse size
• Hard scattering factorization and light cone hamiltonian approach to diffractive processes
• Snowmass 2021 White Paper: Electron Ion Collider for High Energy Physics
• Color transparency in deeply inelastic diffraction
• Diffractive Parton Distributions in the Semiclassical Approach