31st International Workshop on Deep Inelastic Scattering

TMD factorisation for diffractive jets in photon-nucleus interaction

Non programmé

20m

Maison MINATEC, Grenoble, FRANCE

Regular parallel talk WG2: Small-x, Diffraction and Vector Mesons

Orateur

Sigtryggur Hauksson (IPhT, CEA, Université Paris-Saclay)

Description

We argue that diffractive jet production in photon-nucleus interactions at high energy represents a golden channel to study gluon saturation at the future Electron-Ion Collider. The most interesting process in that sense is the diffractive production of a pair of hard jets with transverse momenta much larger than the saturation momentum $Q_s$ of the nuclear target. We show that the dominant contribution to the cross-section comes from (2+1)-jet processes in which the hard dijet is accompanied by a third, semi-hard, jet, which can be sourced either by a quark or a gluon and which has a transverse momentum of the order of $Q_s$. Such (2+1)-jet configurations allow for strong scattering and hence are not suppressed by the color transparency of small dipoles. When computed within the color dipole picture, the cross-section for 2+1 diffractive jets exhibits transverse-momentum dependent (TMD) factorisation: it can be written as the product of a hard factor describing the hard dijet and a partonic (quark or gluon) diffractive TMD, which represents an unintegrated parton distribution of the Pomeron. By combining the color dipole picture with the color glass condensate (CGC) effective theory, we obtain leading-order estimates for the quark and gluon diffractive TMDs. We also compute the diffractive PDFs and demonstrate their DGLAP evolution in the framework of the dipole picture.