Causal-Horizon Scaling of Quarkonium Suppression in Strong QCD Fields

Abstract

The simultaneous observation of strong sequential suppression and small azimuthal anisotropy for bottomonium states provides a stringent constraint on the time scale and geometry of the suppression mechanism. We propose an early-time geometric survival mechanism in which the strong pre-equilibrium color field induces a local proper acceleration and an associated Unruh causal scale. The survival probability is modeled by a WKB-motivated exponential controlled by the ratio of the quarkonium radius to the causal horizon. Combined with CGC-inspired centrality and energy scaling, the framework gives a compact description of the $Υ(1S, 2S, 3S)$ suppression pattern and predicts a definite RHIC/LHC energy dependence. Because the suppression acts as a local scalar factor before hydrodynamic response develops, it naturally produces little additional quarkonium momentum anisotropy.