Speaker
Description
At lower collision energies, baryon stopping becomes increasingly important, resulting in a baryon-rich medium and pronounced baryon-antibaryon differences in the collective flow coefficients, particularly $v_1$ and $v_2$. A quantitative description of these splittings requires a realistic treatment of the initial net-baryon distribution. While hydrodynamic models with finite baryon density have made significant progress, the predicted flow splitting remains sensitive to the assumed initial baryon profile. Conventional prescriptions often use a factorized ansatz in which the transverse and longitudinal structures of baryon deposition are treated independently.
In this work, we introduce a novel local participant density-dependent baryon deposition ansatz in which the longitudinal rapidity distribution of the deposited baryon number is correlated with its transverse position due to collision geometry. Specifically, the rapidity loss of each participant nucleon is determined by the local density of participants from the opposing nucleus. Regions experiencing a larger opposing participant density therefore undergo stronger baryon stopping, while regions encountering lower density experience a smaller rapidity loss.
We combine this new baryon deposition with a tilted initial energy-density profile and evolve the resulting matter using a relativistic hydrodynamic framework that consistently incorporates finite net-baryon density and baryon diffusion. We demonstrate that the resulting framework provides a simultaneous description of the baryon–antibaryon splitting in both $v_1$ and $v_2$. Our study establishes a physically motivated initial-state framework for baryon-rich matter at RHIC BES energies and provides a unified baseline for investigating observables sensitive to finite baryon density. In particular, the framework can serve as a foundation for future studies of fluctuations and transport phenomena relevant to the search for the QCD critical point.