Impact of Nuclear Deformation on Relativistic Heavy-Ion Collisions: Assessing Consistency in Nuclear Physics across Energy Scales

Abstract:

In the hydrodynamic framework of heavy-ion collisions, elliptic flow $v_2$ is sensitive to the quadrupole deformation $\beta$ of the colliding ions. This enables one to test whether the established knowledge on the low-energy structure of nuclei is consistent with collider data from high-energy experiments. We derive a formula based on generic scaling laws of hydrodynamics to relate the difference in $v_2$ measured between collision systems that are close in size to the value of $\beta$ of the respective species. We validate our formula in simulations of $238U+238U$ and $197\mathrm{Au}+197\mathrm{Au}$ collisions at top Relativistic Heavy Ion Collider (RHIC) energy, and subsequently apply it to experimental data. Using the deformation of $238U$ from low-energy experiments, we find that RHIC $v_2$ data implies $0.16\lesssim \left|\beta \right|\lesssim 0.20$ for $197\mathrm{Au}$ nuclei, i.e., significantly more deformed than reported in the literature, posing an interesting issue in nuclear phenomenology.

G. Giacalone, J. Jia, C. Zhang, “Impact of Nuclear Deformation on Relativistic Heavy-Ion Collisions: Assessing Consistency in Nuclear Physics across Energy Scales”, Phys. Rev. Lett. 127, 242301 (2021).

https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.127.242301

Related to Project C06