Eccentricity and elliptic flow in pp collisions at the LHC

TL;DR

This paper investigates the potential for collective phenomena like elliptic flow in high-multiplicity proton-proton collisions at the LHC using a new Monte Carlo generator that models proton shape fluctuations.

Contribution

It introduces the DIPSY event generator with advanced BFKL dynamics to predict eccentricity and elliptic flow in pp collisions, including the effects of proton shape fluctuations.

Findings

Eccentricity increases with multiplicity.

Elliptic flow magnitude can be estimated from eccentricity.

Sign change in four-particle azimuthal correlation indicates flow presence.

Abstract

High-multiplicity proton-proton collisions at the LHC may exhibit collective phenomena such as elliptic flow. We study this issue using DIPSY, a brand-new Monte Carlo event generator which features almost-NLO BFKL dynamics and describes the transverse shape of the proton including all fluctuations. We predict the eccentricity of the collision as a function of the multiplicity and estimate the magnitude of elliptic flow. We suggest that flow can be signaled by a sign change in the four-particle azimuthal correlation.