Exclusive $J/\ddot{I}ˆ$ production at the LHC in the $k_T$ factorization approach

Abstract

The recent LHCb data for exclusive $J/\ddot{I}ˆ$ peripheral production at 13 TeV motivate an improved `NLO' analysis to estimate the gluon distribution at low $x$ in which we re-calculate the rapidity gap survival factors and use a more precise expression for the photon flux. We comment on the difference between the $k_T$ and collinear factorization approaches.

9 pages, 2 figures. Version to appear in J.Phys.G (Letters)