Constraints On The Momentum Dependence Of The Nuclear Symmetry Potential Based On Heavy Ion Collisions

Heavy ion collisions can directly produce high-density and high-temperature Nuclear matter,which provides an opportunity to explore the properties of strongly interacting matter under extreme conditions.Therefore,it has become an important research method to study the equation of state of Nuclear matter and its symmetric energy terms,which is a hot topic in the field of nuclear physics.The isospin dependence of strong interaction,that is,symmetry energy,plays an important role in studying the structure of unstable nuclei and understanding many physical phenomena in nuclear physics and nuclear astrophysics.It directly affects the properties of unstable atomic nuclei,the dynamic process of heavy ion collisions,the mass radius and cooling evolution mechanism of neutron star,and is of great significance to the research of supernova explosion and nuclear synthesis in celestial bodies.The equation of state of asymmetric Nuclear matter,especially its nuclear symmetric energy term,also plays a crucial role in studying the structure and evolution of radioactive nuclei and the synthesis of intermediate and heavy nuclei.Symmetry energy characterizes the change of equation of state from symmetric Nuclear matter to pure neutron matter,especially when the density is about twice the saturation density of ρ0,the symmetry energy is closely related to neutron star matter,The symmetry energy is closely related to the neutron star matter,and the neutron star mass radius and the deformation of neutron star merging time are also closely related to the symmetry energy.In the transport model,we investigated the differential transverse flow of neutrons protons and its excitation function in the 132Sn+124Sn central collision at 270 MeV/nucleon,and verified the influence of momentum dependence on meson observations.In order to more accurately estimate the impact of the high-density behavior of symmetry energy on mesons,we also considered the uncertainty of symmetry energy near saturation density ρ0,and used the symmetry potential Usym∞(ρ0)at saturation density when the nucleon momentum is infinite to characterize the momentum dependence of the nucleon momentum.The motion of high-energy nucleons is directly influenced by the symmetry energy and its slope at saturation density of L,thus providing the possibility of directly detecting high-density symmetry energy.This is because the high-energy participants can originate from the compressed region in the early stage of the heavy ion collision and be accelerated by the symmetry potential,so that their momentum reflects the symmetry energy and its L value.The research results indicate that the neutron proton differential transverse flow and its excitation function are mainly sensitive to the slope L of the ρ0 symmetric energy at saturation density.However,the impact of the low density behavior of symmetric energy on this observable result should also be considered.Therefore,measuring the neutron proton differential transverse flow and its excitation function can provide a useful supplement to the L constraint for extracting the transverse momentum spectral ratio in SπRIT experiments.At the same time,under certain L conditions,the characteristic parameter Usym∞(ρ0)of the symmetric potential has a significant impact on the generation and ratio of π-and π+.In addition,by comparing the charged meson yields,meson ratios,and transverse momentum spectral ratios of the 108Sn+112Sn and 132Sn+124Sn reactions with the corresponding data in the SπRIT experiment,we found that our results support Usym∞(ρ0=-160-9+18 MeV and 62.7<L<93.1 MeV.In addition,the results also indicate that the mesons generated in the 197Au+197 Au collisions at 400 MeV/nucleon also support a value of Usym∞(ρ0).