Speaker
Description
We consider the differential cross-section for single-inclusive jet production with transverse momentum P⊥ in Deep Inelastic Scattering (DIS) at small Bjorken xBj, mediated by a virtual photon with virtuality Q2. We focus on the kinematic regime where the jet is produced in the target fragmentation hemisphere of the Breit frame, and with P⊥ ≪ Q. For a longitudinally polarised photon, we demonstrate that this cross section is not power of P⊥/Q suppressed and we derive a factorized expression in terms of transverse momentum dependent (TMD) quark and gluon fracture functions. Our formula, valid at next-to-leading order in αs at small x, is akin to the Altarelli-Martinelli identity for the longitudinal DIS structure-function. Numerical estimates show that the quark TMD fracture function is the most sensitive to saturation effects in large nuclei.
