Azimuthal asymmetries for hadron distributions inside jets in hadronic collisions

TL;DR

This paper investigates azimuthal asymmetries in hadron distributions within jets produced in hadronic collisions, using a generalized parton model that includes spin and intrinsic motion effects, focusing on observable asymmetries related to various TMD functions.

Contribution

It introduces a comprehensive analysis of azimuthal asymmetries in jet fragmentation, incorporating all allowed TMD functions and considering both quark and gluon contributions, under the assumption of factorization.

Findings

Identification of leading-twist azimuthal asymmetries for unpolarized and polarized cases.

Analysis of the roles of Sivers, Boer-Mulders, transversity, and Collins functions.

Framework applicable to experimental measurements of azimuthal distributions.

Abstract

Using a generalized parton model approach including spin and intrinsic parton motion effects, and assuming the validity of factorization for large p_T jet production in hadronic collisions, we study the azimuthal distribution around the jet axis of leading pions, produced in the jet fragmentation process. We identify the observable leading-twist azimuthal asymmetries for the unpolarized and single-polarized case related to both quark and gluon-originated jets. We account for all physically allowed combinations of the transverse momentum dependent (TMD) parton distribution and fragmentation functions, with special attention to the Sivers, Boer-Mulders, and transversity quark distributions, and to the Collins fragmentation function for quarks (and to the analogous functions for gluon partons).