Central $\mu^{+}\mu^{-}$ production via photon-photon fusion in proton-proton collisions with proton dissociation

TL;DR

This paper develops a photon flux formalism including transverse momenta for proton-proton collisions, compares it with existing methods, and analyzes various production mechanisms relevant for LHC experiments.

Contribution

It introduces a new formalism incorporating photon transverse momenta in two-photon production, validated against LPAIR, enhancing the study of correlation observables in proton collisions.

Findings

Good agreement with LPAIR code results.

Similar contributions from all mechanisms under typical cuts.

Cross sections depend on the $F_2$ structure function in different kinematic regions.

Abstract

We present a formalism which uses fluxes of equivalent photons including transverse momenta of the intermediate photons. The formalism reminds the familiar $k_t$-factorization approach used, e.g., to study the two-photon production of $c\bar{c}$ or $b\bar{b}$ pairs. The results of the new method are compared with those obtained using the code LPAIR, and a good agreement is obtained. The inclusion of the photon transverse momenta is necessary in studies of correlation observables. We present distributions for the dimuon invariant mass, transverse momentum of the muon pair and relative azimuthal angle between muons separately for elastic-elastic, elastic-inelastic, inelastic-elastic and inelastic-inelastic mechanisms. For typical experimental cuts all mechanisms give similar contributions. The results are shown for different sets of cuts relevant for the LHC experiments. The cross sections in different regions of phase space depend on $F_2$ structure function in different regions of $x$ and $Q^2$. A comment on $F_2$ is made.