Probing neutron-skin thickness with free spectator neutrons in ultracentral high-energy isobaric collisions

Abstract

We show that the yield ratio of free spectator neutrons produced in high-energy ${}^{96}$Zr+${}^{96}$Zr to ${}^{96}$Ru+${}^{96}$Ru collisions is a clean probe of the neutron-skin thickness of colliding nuclei and the slope parameter $L$ of the symmetry energy. The idea is demonstrated based on the proton and neutron density distributions via a state-of-the-art Skyrme-Hartree-Fock-Bogolyubov calculation. Among spectator nucleons given by the Glauber model, free spectator neutrons include those from direct production that survive from clusterization as well as those from deexcitation of heavy clusters described by the popular GEMINI model. More free neutrons are produced in collisions of ${}^{96}$Zr nucleus due to its larger neutron skin, compared to those produced in collisions of ${}^{96}$Ru nucleus with a smaller neutron skin. The difference of the free spectator neutron yield is further increased with the increasing difference of the neutron-skin thickness between ${}^{96}$Zr and ${}^{96}$Ru with a larger $L$ value, and the increase in ultracentral collisions is particularly insensitive to model details and experimental uncertainties. Since the production of free spectator neutrons is not affected by the complicated dynamics in the mid-rapidity region, the ratio of their multiplicities in ultracentral isobaric collisions is a robust observable for constraining the neutron skin and $L$ value.

6 pages, 4 figures

References in corpus (18)

• Neutron Star Observations: Prognosis for Equation of State Constraints
• Neutron-Rich Nuclei in Heaven and Earth
• Accurate Determination of the Neutron Skin Thickness of ${}^{208}$Pb through Parity-Violation in Electron Scattering
• Surface diffuseness correction in global mass formula
• Nuclear symmetry energy probed by neutron skin thickness of nuclei
• Implications of PREX-II on the equation of state of neutron-rich matter
• Axially deformed solution of the Skyrme-Hartree-Fock-Bogolyubov equations using the transformed harmonic oscillator basis (II) HFBTHO v2.00d: a new version of the program
• Neutron density distributions from antiprotonic 208Pb and 209Bi atoms
• Light nuclei quasiparticle energy shift in hot and dense nuclear matter
• Proton elastic scattering from tin isotopes at 295 MeV and systematic change of neutron density distributions
• Probing triaxial deformation of atomic nuclei in high-energy heavy ion collisions
• Evidence of the triaxial structure of ${}^{129}$Xe at the Large Hadron Collider
• Implications of PREX-2 on the electric dipole polarizability of neutron rich nuclei
• Bayesian inference of nuclear symmetry energy from measured and imagined neutron skin thickness in ${}^{116,118,120,122,124,130,132}$Sn, ${}^{208}$Pb, and ${}^{48}$Ca
• Probing nuclear quadrupole deformation from correlation of elliptic flow and transverse momentum in heavy ion collisions
• Beam Energy dependence of Light Nuclei Production in Au+Au Collisions
• A Centrality Detector Concept
• Incorporating the weak mixing angle dependence to reconcile the neutron skin measurement on 208Pb by PREX-II

Cited by in corpus (17)

• Separating the impact of nuclear skin and nuclear deformation in high-energy isobar collisions
• Probing the nuclear deformation with three-particle asymmetric cumulant in RHIC isobar runs
• Free spectator nucleons in ultracentral relativistic heavy-ion collisions as a probe of neutron skin
• Measuring deformed neutron skin with free spectator nucleons in relativistic heavy-ion collisions
• Non-Gaussian transverse momentum fluctuations from impact parameter fluctuations
• Methods for systematic study of nuclear structure in high-energy collisions
• Probing configuration of $\alpha$ clusters with spectator particles in relativistic heavy-ion collisions
• Impact of initial fluctuations and nuclear deformations in isobar collisions
• Effect of nuclear structure on particle production in relativistic heavy-ion collisions using the AMPT model
• Directly probing existence of $\alpha$-cluster structure in ${}^{20}$Ne by relativistic heavy-ion collisions
• Peeling away neutron skin in ultracentral collisions of relativistic nuclei
• An overview of new measurements of flow, chirality, and vorticity from STAR experiment
• Probing Nuclear Geometry through Multi-Particle Azimuthal Correlations and Rapidity-Even Dipolar Flow in ${}^{16}$O+${}^{16}$O Collisions
• The size of the quark-gluon plasma in ultracentral collisions: impact of initial density fluctuations on the average transverse momentum
• Investigating the possibility of extracting neutron-skin thickness in nuclei by their collisions at intermediate energies
• Exploring Rapidity-Even Dipolar Flow in Isobaric Collisions at RHIC
• A novel filtering method for generating desired density profiles of colliding nuclei