production in polarized and unpolarized ep collision and Sivers and asymmetries

Asmita Mukherjee; Sangem Rajesh

doi:10.1140/epjc/s10052-017-5406-4

EPJ

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2023 Impact factor 4.2

Particles and Fields

Open Access

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

Regular Article - Theoretical Physics

$J/\psi$ production in polarized and unpolarized ep collision and Sivers and $\cos 2\phi$ asymmetries

Asmita Mukherjee^* and Sangem Rajesh

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 $\cos 2\phi$ azimuthal asymmetries in $J/\psi$ 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 $J/\psi$ production rate. The Sivers asymmetry in this process directly probes the gluon Sivers function. The estimated Sivers asymmetry at $$z=1$$ is negative, which is in good agreement with the COMPASS data. The effect of TMD evolution on the Sivers asymmetry is also investigated. The $\cos 2\phi$ asymmetry is sizable and probes the linearly polarized gluon distribution in an unpolarized proton.