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

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.