The ridge in proton-proton collisions at the LHC

TL;DR

This paper explains the ridge correlation observed in high multiplicity proton-proton collisions at the LHC using the Color Glass Condensate framework, linking it to similar phenomena in heavy-ion collisions.

Contribution

It demonstrates that the ridge in proton-proton collisions can be understood within the Color Glass Condensate formalism, unifying it with heavy-ion collision phenomena.

Findings

The ridge correlation can be explained by high energy QCD effects.

The same formalism applies to both proton-proton and heavy-ion collisions.

Flow effects may enhance the observed signals in heavy-ion collisions.

Abstract

We show that the key features of the CMS result on the ridge correlation seen for high multiplicity events in sqrt(s)=7TeV proton-proton collisions at the LHC can be understood in the Color Glass Condensate framework of high energy QCD. The same formalism underlies the explanation of the ridge events seen in A+A collisions at RHIC, albeit it is likely that flow effects may enhance the magnitude of the signal in the latter.