Imaging shapes of ground-state uranium-238 nuclei in high-energy nuclear collisions at RHIC

Abstract

The shape and orientation of colliding nuclei play a crucial role in determining the initial conditions of the quark-gluon plasma (QGP), which influence key observables such as anisotropic and radial flow. In these proceedings, we present the measurements of $v_2$, $p_{\rm T}$ fluctuations and $v_2-p_{\rm T}$ correlations in $^{238}$U + $^{238}$U and $^{197}$Au + $^{197}$Au collisions at center of mass energies $\sqrt{s_{\rm NN}}=$ 193 and 200 GeV, respectively. Our results reveal significant differences in these observables between the two systems, particularly in the most central collisions. Comparisons with hydrodynamic model calculations indicate a large deformation in the ground states of $^{238}$U nuclei, consistent with previous low-energy experiments. However, data also imply a small deviation from axial symmetry of $^{238}$U [1]. Our work introduces a novel approach for imaging nuclear shapes, enhances the modeling of QGP initial conditions, and sheds light on nuclear structure evolution across different energy scales. The potential applications of this method for other nuclear species are discussed.