Elliptic and triangular flow in p+Pb and peripheral Pb+Pb collisions from parton scatterings

TL;DR

This study uses the AMPT model to analyze elliptic and triangular flow coefficients in p+Pb and Pb+Pb collisions, successfully reproducing some experimental data and providing new predictions for higher order flow coefficients.

Contribution

It demonstrates the capability of the AMPT model to describe flow coefficients in small and peripheral heavy-ion collisions and offers predictions for higher order Fourier coefficients.

Findings

v_3 matches CMS data well

v_2 is well described in p+Pb but underestimated at high p_T in Pb+Pb

Both v_2 and v_3 increase from proton to Pb-nucleus side

Abstract

Using a multiphase transport model (AMPT) we calculate the elliptic, $v_2$, and triangular, $v_3$, Fourier coefficients of the two-particle azimuthal correlation function in proton-nucleus (p+Pb) and peripheral nucleus-nucleus (Pb+Pb) collisions. Our results for $v_3$ are in a good agreement with the CMS data collected at the Large Hadron Collider. The $v_2$ coefficient is very well described in p+Pb collisions and is underestimated for higher transverse momenta in Pb+Pb interactions. The characteristic mass ordering of $v_2$ in p+Pb is reproduced whereas for $v_3$ this effect is not observed. We further predict the pseudorapidity dependence of $v_2$ and $v_3$ in p+Pb and observe that both are increasing when going from a proton side to a Pb-nucleus side. Predictions for the higher order Fourier coefficients, $v_4$ and $v_5$, in p+Pb are also presented.