From deep-inelastic structure functions to two-photon dilepton production in proton-proton collisions

TL;DR

This paper compares collinear and $k_T$-factorization approaches for calculating dilepton production in proton-proton collisions, analyzing their sensitivity to structure functions and experimental cuts, and contrasting results with experimental data.

Contribution

It introduces a comparison between two theoretical approaches for photon-photon induced dilepton production and evaluates their agreement with experimental measurements.

Findings

Photon-photon contribution is generally small in most cases.

Results are sensitive to structure function parametrization and experimental cuts.

The study suggests ways to enhance the photon-photon contribution.

Abstract

We compare two different approaches used for calculating cross sections for the two-photon $p p \to l^+ l^- X$ process. In one of the approaches photon is treated as a collinear parton in the proton. In the second approach a recently proposed $k_T$-factorization method is used. In this presentation we discuss sensitivity of the results to the choice of structure function parametrization and experimental cuts in the $k_T$-factorization approach. We compare results of our calculations with recent experimental data for dilepton production and find that in most cases the contribution of the photon-photon mechanism is rather small. We discuss how to enhance the photon-photon contribution. We also compare our results to those of recent measurements of exclusive and semi-exclusive $e^+ e^-$ pair production with certain experimental data by the CMS collaboration.