Investigating 238U deformation via dilepton production in relativistic heavy-ion collisions

Due to their weak coupling to the strongly interacting matter produced in relativistic heavy-ion collisions, dileptons serve as a sensitive probe of the initial geometry of the colliding nuclei. In this study, we investigate the influence of initial nuclear quadrupole deformation, characterized by the parameter β 2 , on dilepton production in U + U collisions at s N N = 193 GeV. The analysis is carried out using a modified multiphase transport model in which partonic interactions are described by the Nambu–Jona-Lasinio model. We observe a clear linear dependence of dilepton yields on β 2 2 in both the low-mass region (LMR, < 1 GeV/ c 2 ) and intermediate-mass region (IMR, 1 − 3 GeV / c 2 ) of the dilepton spectrum for the most central collisions. Also, dilepton production in the IMR region exhibits a stronger sensitivity to nuclear deformation than in the LMR, reflecting the dominance of earlier partonic processes in this mass range. These results suggest that precise measurements of dilepton yields in relativistic heavy-ion collisions can provide a complementary probe of the nuclear deformation parameter β 2 of 238 U, offering additional insights when combined with constraints from low-energy experiments and flow-related probes in high-energy experiments.