Saturation and geometrical scaling in small systems

TL;DR

This paper discusses how saturation and geometrical scaling in small systems like proton-proton and proton-nucleus collisions relate to QCD non-linear evolution, emphasizing the inelastic cross-section and proton saturation scale fluctuations.

Contribution

It proposes that geometrical scaling applies to the inelastic cross-section in pp collisions and explores proton saturation scale fluctuations in pA collisions at the LHC.

Findings

GS holds for the inelastic cross-section in pp collisions

Proton saturation scale fluctuates in pA collisions at the LHC

Discussion of non-linear QCD evolution effects

Abstract

Saturation and geometrical scaling (GS) of gluon distributions are a consequence of the non-linear evolution equations of QCD. We argue that in pp GS holds for the inelastic cross-section rather than for the multiplicity distributions. We also discuss possible fluctuations of the proton saturation scale in pA collisions at the LHC.