1304.2584 (Rohini M. Godbole et al.)

Transverse Single Spin Asymmetry in $e+p^\uparrow \to e+J/ψ+X $ and
Transverse Momentum Dependent Evolution of the Sivers Function    [PDF]

Rohini M. Godbole, Anuradha Misra, Asmita Mukherjee, Vaibhav S. Rawoot

We extend our analysis of transverse single spin asymmetry (SSA) in electroproduction of $J/\psi $ to include the effect of the scale evolution of the transverse momentum dependent (TMD) parton distribution functions and gluon Sivers function. We estimate SSA for JLab, HERMES, COMPASS and eRHIC energies using color evaporation model of charmonium production, using an analytically obtained approximate solution of TMD evolution equations discussed in literature. We find that there is a reduction in the asymmetry compared with our predictions for the earlier case considered by us, wherein the $Q^2$ - dependence came only from DGLAP evolution of the unpolarised gluon densities and which used a different paameterisation of the TMD Sivers function.

View original: http://arxiv.org/abs/1304.2584