Speaker
Description
Semi-inclusive deep inelastic scattering (SIDIS) with a hadron measured in the final state is a well-established observable to probe the three-dimensional momentum structure of nucleons and nuclei, in particular at small Bjorken $x$ where the cross-section factorizes in terms of a sea quark transverse momentum (TMD) distribution [1]. However, to extract TMDs from hadron measurements, one needs precise knowledge of the corresponding TMD fragmentation functions into hadron. An alternative is to consider the production of jets, which provide a clean, pQCD-controlled final state. Understanding how TMD factorization applies to jets in SIDIS, however, is far from straightforward.
In this talk, based on [2], we address this question in the small-$x$ limit of SIDIS. Using the colour dipole picture of Deep Inelastic Scattering and the Colour Glass Condensate effective theory, we study semi-inclusive jet production in DIS in the regime where the photon virtuality $Q^2$ is much larger than the jet transverse momentum squared $P_\perp^2$. We show that physically meaningful jet definitions are those where the effective jet axis is set by the virtuality of the struck quark rather than its transverse momentum. For such definitions, the next-to-leading order (NLO) cross-section factorizes in terms of the sea quark TMD, which obeys universal Dokshitzer-Gribov-Lipatov-Altarelli-Parisi (DGLAP) and Collins-Soper-Sterman (CSS) evolution.
Our results provide a solid theoretical framework for performing and interpreting jet measurements in SIDIS at the future EIC and for mapping the TMD parton distributions of nuclei at high energies.
[1] Marquet, Xiao, Yuan, Phys.Lett.B 682 (2009)
[2] Caucal, Iancu, Mueller, Yuan, Phys.Rev.Lett. 134 (2025) 6, 6
| Speaker confirmation | Yes |
|---|