Sivers and Boer-Mulders functions in Light-Cone Quark Models
B. Pasquini, F. Yuan
TL;DR
This work develops a light-cone quark-model framework to study naïve-T-odd quark distributions, focusing on the Sivers and Boer-Mulders functions. By modeling final-state interactions via single-gluon exchange and employing light-cone wave-function overlaps, it links Sivers and Boer-Mulders to interference among different orbital angular momentum components of the nucleon. The authors derive explicit expressions for the Sivers function through gauge-link expansion and LCWF overlaps, highlighting the role of Melosh rotations in generating orbital angular momentum. The results align favorably with phenomenological parametrizations, supporting the framework's use for azimuthal asymmetries in hadronic processes and motivating further exploration of the Boer-Mulders function.
Abstract
Results for the naive-time-reversal-odd quark distributions in a light-cone quark model are presented. The final-state interaction effects are generated via single-gluon exchange mechanism. The formalism of light-cone wave functions is used to derive general expressions in terms of overlap of wave-function amplitudes describing the different orbital angular momentum components of the nucleon. In particular, the model predictions show a dominant contribution from S- and P-wave interference in the Sivers function and a significant contribution also from the interference of P and D waves in the Boer-Mulders function. The favourable comparison with existing phenomenological parametrizations motivates further applications to describe azimuthal asymmetries in hadronic reactions.