Recent progress in some exclusive and semi-exclusive processes in proton-proton collisions

TL;DR

This paper reviews recent advances in exclusive and semi-exclusive processes in proton-proton collisions, focusing on vector charmonia and dilepton production, with comparisons to LHCb and CMS experimental data.

Contribution

It introduces a new approach similar to $k_t$-factorization for $ ext{γγ}$ production and includes helicity flip contributions and absorption corrections.

Findings

Results agree with LHCb data on charmonia production.

Dilepton production results are consistent with CMS measurements.

Uncertainties mainly stem from the $F_2$ structure function.

Abstract

We present the main results of our recent analyses of exclusive production of vector charmonia ($J/\psi$ and $\psi'$) in $k_t$-factorization approach and for $\gamma \gamma$ production of charged dilepton pairs in exclusive and semiinclusive processes in a new approach, similar in spirit to $k_t$-factorization. The results for charmonia are compared with recent results of the LHCb collaboration. We include some helicity flip contributions and quantify the effect of absorption correction. The effect of $c \bar c$ wave function is illustrated. We present uncertainties related to $F_2$ structure function which are the main ingredient of the approach. Our results are compared with recent CMS data for dilepton production with lepton isolation cuts imposed.