Two-particle Bose-Einstein correlations in pp collisions at ${\sqrt{s} = 13}$ TeV measured with the ATLAS detector at the LHC

TL;DR

This study measures Bose-Einstein correlations in proton-proton collisions at 13 TeV using ATLAS data, analyzing how correlation parameters depend on multiplicity and transverse momentum, and confirming radius saturation at high multiplicity.

Contribution

It provides the first detailed measurement of BEC parameters at 13 TeV, exploring their dependence on multiplicity and transverse momentum with high precision.

Findings

BEC radius is independent of multiplicity above 100

Confirmation of radius saturation at high multiplicity

Analysis covers two different transverse momentum ranges

Abstract

This paper presents studies of Bose-Einstein correlations (BEC) in proton-proton collisions at a centre-of-mass energy of 13 TeV, using data from the ATLAS detector at the CERN Large Hadron Collider. Data were collected in a special low-luminosity configuration with a minimum-bias trigger and a high-multiplicity track trigger, accumulating integrated luminosities of 151 $\mu$b$^{-1}$ and 8.4 nb$^{-1}$ respectively. The BEC are measured for pairs of like-sign charged particles, each with $|\eta|$ < 2.5, for two kinematic ranges: the first with particle $p_T$ > 100 MeV and the second with particle $p_T$ > 500 MeV. The BEC parameters, characterizing the source radius and particle correlation strength, are investigated as functions of charged-particle multiplicity (up to 300) and average transverse momentum of the pair (up to 1.5 GeV). The double-differential dependence on charged-particle multiplicity and average transverse momentum of the pair is also studied. The BEC radius is found to be independent of the charged-particle multiplicity for high charged-particle multiplicity (above 100), confirming a previous observation at lower energy. This saturation occurs independent of the transverse momentum of the pair.