Disentangling effects of collision geometry and symmetry energy in U+U collisions

TL;DR

This study investigates how collision geometry influences observables sensitive to nuclear symmetry energy in U+U collisions at 0.52 GeV/nucleon, revealing geometry-dependent sensitivities to high-density symmetry energy effects.

Contribution

It demonstrates that collision geometry significantly affects the sensitivity of various observables to the symmetry energy in U+U collisions, providing new insights into high-density nuclear matter.

Findings

Neutron-proton differential flow is more sensitive in tip-tip collisions.

Neutron-proton elliptic flow difference is more sensitive in body-body collisions.

The / ratio of pre-equilibrium nucleons is slightly more sensitive in tip-tip collisions.

Abstract

Effects of the collision geometry on experimental observables that are known to be sensitive to the high-density behavior of nuclear symmetry energy are examined in U+U collisions at 0.52 GeV/nucleon using an isospin- and momentum-dependent interaction within the framework of IBUU transport model. It is found that the neutron-proton differential flow in tip-tip collisions and the difference of neutron and proton elliptic flow in body-body collisions are more sensitive to the symmetry energy at supra-saturation densities compared with collisions of spherical nuclei of the same masses. In addition, the n/p ratio of pre-equilibrium nucleons is found to be slightly more sensitive to the symmetry energy in tip-tip collisions, and the collision geometry affects the \pi^-/\pi^+ ratio significantly.