Baseline predictions of elliptic flow and fluctuations for the RHIC Beam Energy Scan using response coefficients
Skandaprasad Rao, Matthew D. Sievert, Jacquelyn Noronha-Hostler
Abstract
Currently the Relativistic Heavy Ion Collider (RHIC) Beam Energy Scan is exploring a new region of the quantum chromodynamic phase diagram at large baryon densities that approaches nuclear astrophysics regimes. This provides an opportunity to study relativistic hydrodynamics in a regime where the net conserved charges of baryon number, strangeness, and electric charge play a role, which will significantly change the theoretical approach to simulating the baryon-dense quark-gluon plasma. Here we detail many of the important changes needed to adapt both initial conditions and the medium to baryon-rich matter. Then, we make baseline predictions (i.e., assuming a high-energy approach) for the elliptical flow and fluctuations based on extrapolating the physics at Large Hadron Collider and top RHIC energies to support future analyses of where and how the new baryon-dense physics causes these extrapolations to break down. First we compare eccentricities across beam energies, exploring their underlying assumptions; we find the extrapolated initial state is predicted to be nearly identical to that at AuAu $\sqrt{{s}_{NN}}=200$ GeV. Then we make exploratory predictions of the final flow harmonic based on linear $+$ cubic response. We discuss preliminary STAR results in order to determine the implications that they have for linear $+$ cubic response coefficients at the lowest beam energy of AuAu $\sqrt{{s}_{NN}}=7$ GeV.