Correlation between mean transverse momentum and anisotropic flow in heavy-ion collisions
Giuliano Giacalone, Fernando G. Gardim, Jacquelyn Noronha-Hostler, Jean-Yves Ollitrault
Abstract
The correlation between the mean transverse momentum of outgoing particles, $\ensuremath{\langle}{p}_{t}\ensuremath{\rangle}$, and the magnitude of anisotropic flow, ${v}_{n}$, has recently been measured in $\mathrm{Pb}+\mathrm{Pb}$ 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 $\ensuremath{\langle}{p}_{t}\ensuremath{\rangle}$ 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, ${\ensuremath{\varepsilon}}_{n}$, and $\ensuremath{\langle}{p}_{t}\ensuremath{\rangle}$ by the total energy per unit rapidity of the fluid at the beginning of the hydrodynamic expansion.