$J/ψ$-meson production within improved color evaporation model with the $k_{T}$-factorization approach for $c\bar{c}$ production

Rafal Maciula; Antoni Szczurek; Anna Cisek

Paper

$J/ψ$-meson production within improved color evaporation model with the $k_{T}$-factorization approach for $c\bar{c}$ production

Abstract

We use a new approach to color evaporation model (CEM) for quarkonium production. The production of

pairs is performed within

-factorization approach using different unintegrated gluon distribution functions (UGDF) from the literature. We include all recent improvements to color evaporation model. We cannot describe simultaneously mid and forward rapidity data measured at the LHC when using the KMR UGDF with the same normalization parameter. Furthermore we get somewhat too hard distribution in

transverse momentum. Correcting the standard KMR distributions for saturation effects at small values of

improves

rapidity distributions, while taking correction for emissions hidden in the KMR UGDF in the evaluation of

values improves a bit

transverse momentum distributions. The modifications improve also description of the LHCb

-meson data.