Correlation between mean transverse momentum and anisotropic flow in heavy-ion collisions

Abstract

The correlation between the mean transverse momentum of outgoing particles, $⟨p_t⟩$, and the magnitude of anisotropic flow, $v_n$, has recently been measured in Pb+Pb collisions at the CERN Large Hadron Collider, as a function of the collision centrality. We confirm the previous observation that event-by-event hydrodynamics predicts a correlation between $v_n$ and $⟨p_t⟩$ that is similar to that measured in data. We show that the magnitude of this correlation can be directly predicted from the initial condition of the hydrodynamic calculation, for $n=2,3$, if one replaces $v_n$ by the corresponding initial-state anisotropy, ${\epsilon }_n$, and $⟨p_t⟩$ by the total energy per unit rapidity of the fluid at the beginning of the hydrodynamic expansion.

Comments: 7 pages; 4 figures; v2: published version