Event-by-event correlations and fluctuations with strongly intensive quantities in heavy-ion collisions with ALICE

Abstract

The strongly intensive quantity Σ is a new observable, introduced recently to the domain of heavy-ion physics. In superposition models which assume independent particle production from statistically identical sources, Σ is insensitive to the number of sources and its fluctuations, contrary to the standard forward-backward correlation coefficient (bcorr). Therefore it provides direct information on the multiplicity correlations and fluctuations from a single source. This paper presents new results on forward-backward correlations studied with the quantity Σ, measured by ALICE at the LHC in Xe–Xe collisions at √sNN = 5.44 TeV and in Pb–Pb collisions at √sNN = 2.76 and 5.02 TeV. These results are compared with ALICE measurements in pp collisions at √s = 13 TeV.