Predictions for Sivers single spin asymmetries in one- and two-hadron electroproduction at CLAS12 and EIC
Abstract
The study of the Sivers effect, describing correlations between the transverse polarization of the nucleon and its constituent (unpolarized) parton's transverse momentum, has been the topic of a great deal of experimental, phenomenological and theoretical effort in recent years. Semi-inclusive deep inelastic scattering measurements of the corresponding single spin asymmetries (SSA) at the upcoming CLAS12 experiment at JLab and the proposed Electron-Ion Collider will help to pinpoint the flavor structure and the momentum dependence of the Sivers parton distribution function describing this effect. Here we describe a modified version of the Monte Carlo event generator that includes the Sivers effect. Then we use it to estimate the size of these SSAs, in the kinematics of these experiments, for both one and two hadron final states of pions and kaons. For this purpose we utilize the existing Sivers parton distribution function (PDF) parametrization extracted from HERMES and COMPASS experiments. Using this modified version of , we also show that the the leading order approximation commonly used in such extractions may provide significantly underestimated values of Sivers PDFs, as in our Monte Carlo simulations the omitted parton showers and non-DIS processes play an important role in these SSAs, for example in the COMPASS kinematics.
Keywords
Cite
@article{arxiv.1502.02669,
title = {Predictions for Sivers single spin asymmetries in one- and two-hadron electroproduction at CLAS12 and EIC},
author = {Hrayr H. Matevosyan and Aram Kotzinian and Elke-Caroline Aschenauer and Harut Avakian and Anthony W. Thomas},
journal= {arXiv preprint arXiv:1502.02669},
year = {2015}
}
Comments
18 pages, 27 figures. V2: updated to version published in PRD, two references have been added and some minor changes done to the text