Forward-backward multiplicity correlations in pp, pPb and Pb+Pb collisions with the ATLAS detector

Understand

Two-particle pseudorapidity correlations are measured in 2.76 TeV Pb+Pb, 5.02 TeV pPb and 13 TeV pp collisions.

• Correlation function is measured using charged particles in the pseudorapidity range $|\eta|<2.4$ with transverse momentum $p_T>0.2$ GeV, and it is measured as a function of event multiplicity, defined by number of charged particles with $|\eta|<2.5$ and $p_T>0.4$ GeV.
• The correlation function is decomposed into a short-range component (SRC) and a long-range component (LRC).
• The SRC differs significantly between the opposite-charge pairs and same-charge pairs, and between the three collision systems at similar multiplicity.