Speaker
Description
The measurement of azimuthal correlations between two particles is a powerful tool to investigate the properties of strongly-interacting nuclear matter created in ultra-relativistic heavy-ion collisions. In particular, studying the near-side and away-side hadron yields associated with trigger particles can provide important information to understand both the jet -medium interaction and hadron production mechanism. We study two-particle correlations with V0 (K0s, Λ/Λ ) and charge hadrons as trigger particles of transverse momentum 8 < pT,trig < 16 GeV/c,and associated charged particles of 1 GeV/c < pT,assoc < pT,trig at mid-rapidity in pp and Pb–Pb collisions at a center-of-mass energy of 5.02 TeV per nucleon pair. After subtracting the contributions of the flow background v2 and v3 , the per-trigger yields are extracted for two-particle azimuthal differences |∆φ| < 0.9 on the near-side and |∆φ − π| < 1.2 on the away-side.
The ratio of the per-trigger yields in Pb–Pb collisions with respect to pp collisions , IAA, is measured in the near-side and away-side in the most central 0–10% collisions. On the near-side,a significant enhancement of IAA from 1.5 to 2 for different particles species is observed at the lowest pT,assoc. On the away-side, suppression to the level of (I AA ≈ 0.6 ) for pT,assoc>3 GeV/c is observed as expected from strong in-medium energy loss while an enhancement reaching 1.4
at the lowest pT,assoc . The data are compared to AMPT, HIJING and EPOS models. Most calculations qualitatively describe the near-side and away-side yield modification at intermediate and high pT,assoc .
