Elastic and quasi-elastic $pp$ and $γ^\star p$ scattering in the Dipole Model

TL;DR

The paper advances Mueller's dipole cascade by incorporating non-leading effects, fluctuations, and confinement to predict quasi-elastic γ*p processes and the t-dependence of elastic pp scattering. By coupling perturbative photon and meson wavefunctions with a hadronic component and a fluctuating dipole cascade, the authors achieve good agreement with DVCS and exclusive vector-meson data, while reproducing pp cross sections and their differential structure. Key findings include the necessity of small proton wavefunction fluctuations and a hadronic-like photon component, as well as the importance of confinement in shaping large-dipole contributions. The work demonstrates robust predictive power of the cascade framework and motivates developing a full event generator for exclusive final states at high energies.

Abstract

We have in earlier papers presented an extension of Mueller's dipole cascade model, which includes sub-leading effects from energy conservation and running coupling as well as colour suppressed saturation effects from pomeron loops via a ``dipole swing''. The model was applied to describe the total and diffractive cross sections in $pp$ and $γ^*p$ collisions, and also the elastic cross section in $pp$ scattering. In this paper we extend the model to describe the corresponding quasi-elastic cross sections in $γ^*p$, namely the exclusive production of vector mesons and deeply virtual compton scattering. Also for these reactions we find a good agrement with measured cross sections. In addition we obtain a reasonable description of the $t$-dependence of the elastic $pp$ and quasi-elastic $γ^\star p$ cross sections.