Three-pion Bose-Einstein correlations measured in proton-proton collisions

TL;DR

This paper reports the first measurement of three-pion Bose-Einstein correlations in proton-proton collisions at 7 TeV, using LHCb data, and interprets the results within the core-halo model to understand hadronisation coherence.

Contribution

It introduces the first analysis of three-pion Bose-Einstein correlations in proton-proton collisions and applies the core-halo model for interpretation.

Findings

Evidence of coherent pion emission.

Parameters of the core-halo model determined.

Correlation measurements vary with charged-particle multiplicity.

Abstract

A study on the Bose-Einstein correlations for triplets of same-sign pions is presented. The analysis is performed using proton-proton collisions at a centre-of-mass energy of $\sqrt{s}$ = 7 TeV, recorded by the LHCb experiment, corresponding to an integrated luminosity of 1.0 fb$^{-1}$. For the first time, the results are interpreted in the core-halo model. The parameters of the model are determined in regions of charged-particle multiplicity. This measurement provides insight into the nature of hadronisation in terms of coherence, showing a coherent emission of pions.