Transverse sphericity of charged particles in minimum bias p-p collision in ALICE at the LHC

TL;DR

This paper investigates how the shape of primary charged particle distributions, measured by transverse sphericity, varies with multiplicity in proton-proton collisions at different energies using ALICE data, revealing trends that challenge current models.

Contribution

It provides the first detailed measurement of transverse sphericity as a function of multiplicity across multiple energies in minimum bias p-p collisions at the LHC.

Findings

Transverse sphericity increases with multiplicity at all energies.

ALICE results differ from Monte Carlo generator predictions at high multiplicity.

Sphericity rises more steeply at low multiplicity.

Abstract

The study of the sphericity of primary charged particles in minimum bias proton-proton collisions at 0.9, 2.76 and 7 TeV with the ALICE detector at the LHC is presented. The mean sphericity as a function of multiplicity is reported for events with different hardness. The ALICE results show a growing transverse sphericity with multiplicity for all collision energies, with a steeper rise at low multiplicity. The tendency of the MC generators is opposite at high multiplicity.