Nuclear Deformation Effects on Charmonium Suppression in Au+Au and U+U Collisions

Abstract

We investigate the impact of intrinsic nuclear deformation and orientation on the yield suppression and momentum anisotropy of charmonia in Au+Au and U+U collisions at the Relativistic Heavy-Ion Collider. The anisotropic nucleon density within the nucleus is parameterized using a modified Woods-Saxon distribution, which is incorporated into the initial distributions of both the heavy quarkonia and the bulk medium energy density. The well-established Boltzmann-type transport equation is utilized to describe the dynamical evolution of quarkonium in the anisotropic bulk medium. Treating quarkonium suppression in Au+Au collisions as a baseline, we find that the momentum-integrated charmonium yield suppression is relatively insensitive to the initial nuclear geometry in deformed U+U collisions. In contrast, the anisotropic flow coefficients ($v_n$) of the charmonium is more sensitive to the nuclear deformation. Furthermore, these observables are also connected with the collision configuration, particularly when distinguishing between tip-tip and body-body orientations in U+U collisions at $\sqrt{s_{NN}} = 193$ GeV. This effect is more pronounced for the excited state due to its smaller binding energy and heightened sensitivity to the initial energy density of the hot QCD medium.