Eur. Phys. J. C (2017) 77: 854
https://doi.org/10.1140/epjc/s10052-017-5406-4

Regular Article - Theoretical Physics

production in polarized and unpolarized ep collision and Sivers and asymmetries

Department of Physics, Indian Institute of Technology Bombay, Mumbai, 400076, India

^* e-mail: mukherjee.asmita@gmail.com

Received: 7 July 2017
Accepted: 22 November 2017
Published online: 11 December 2017

Abstract

We calculate the Sivers and azimuthal asymmetries in production in the polarized and unpolarized semi-inclusive ep collision, respectively, using the formalism based on the transverse momentum-dependent parton distributions (TMDs). The non-relativistic QCD-based color octet model is employed in calculating the production rate. The Sivers asymmetry in this process directly probes the gluon Sivers function. The estimated Sivers asymmetry at is negative, which is in good agreement with the COMPASS data. The effect of TMD evolution on the Sivers asymmetry is also investigated. The asymmetry is sizable and probes the linearly polarized gluon distribution in an unpolarized proton.