# EPS-HEP2021 conference

26-30 July 2021
Zoom
Europe/Berlin timezone

## Measurement of the jet-particle $v_2$ in p–Pb and Pb–Pb collisions at $\sqrt{s_{\rm NN}}=$ 5.02 TeV with ALICE at the LHC

27 Jul 2021, 10:00
15m
Zoom

#### Zoom

Parallel session talk Heavy Ion Physics

Siyu Tang

### Description

In heavy-ion collisions, the observed non-zero second-order azimuthal anisotropy coefficient $v_2$ of particles with high transverse momenta $p_{\rm T}$ is driven by the path-length dependent energy loss of hard partons traveling in the quark-gluon plasma, known as the jet quenching effect. Recent measurements show also a non-zero $v_2$ value for high-$p_{\rm T}$ charged particles at high multiplicities in small collision systems. The origin of this effect is still debated, and various mechanisms, such as parton energy loss in the cold nuclear matter, hydrodynamic evolution in the final state and initial-state gluon correlations, are proposed to describe the observations. In this contribution, the $v_2$ measurements of charged particles in jets at midrapidity (|η|<0.8) in 20–60% semicentral Pb–Pb collisions and 0–10% most central p–Pb collisions at $\sqrt{s_{\rm NN}} =$ 5.02 TeV recorded with the ALICE detector are presented. The particles associated with jets are extracted from the two-particle correlations using a combined fit, and their $v_2$ are calculated with the scalar product method in Pb–Pb collisions and the central-forward correlation method in p–Pb collisions. The comparisons of the jet-particle and inclusive-particle $v_2$ in both p–Pb and Pb–Pb collisions will bring new insight into the understanding of the origin of the high-$p_{\rm T}$ azimuthal anisotropy observed in small collision systems.

Email alice-cc-chairs@cern.ch ALICE ALICE CC chairs