System response to the initial energy-momentum tensor in relativistic heavy-ion collisions

The evolution of a relativistic heavy-ion collision is typically understood as a process that transmutes the initial geometry of the system into the final momentum distribution of observed hadrons, which can be described via a cumulant expansion of the initial distribution of energy density and is represented at leading order as the well-known eccentricity scaling of anisotropic flow. We summarize a proposed extension of this framework to include the contribution from initial momentum-space properties, as encoded in other components of the energy-momentum tensor. Numerical tests validate this proposal.