Multipion Bose-Einstein correlations in pp, p-Pb, and Pb-Pb collisions at the LHC

Submission Date: 
30/12/2015
Article Information
Submission Form
System: 
p-p
System: 
Pb-Pb
System: 
p-Pb
Energy: 
2.76 TeV
Energy: 
5.02 TeV
Energy: 
7 TeV
Abstract Plain Text: 

Three- and four-pion Bose-Einstein correlations are presented in pp, p--Pb, and Pb--Pb collisions at the LHC.
We compare our measured four-pion correlations to the expectation derived from two- and three-pion measurements.
Such a comparison provides a method to search for coherent pion emission.
We also present mixed-charge correlations in order to demonstrate the effectiveness of several analysis procedures such as Coulomb corrections.
Same-charge four-pion correlations in pp and p--Pb appear consistent with the expectations from three-pion measurements.  
However, the presence of non-negligible background correlations in both systems prevent a conclusive statement.
In Pb--Pb collisions, we observe a significant suppression of three- and four-pion Bose-Einstein correlations compared to expectations from two-pion measurements.
There appears to be no centrality dependence of the suppression within the 0--50\% centrality interval.  
The origin of the suppression is not clear.  However, by postulating either coherent pion emission or large multibody Coulomb effects, the suppression may be explained.