Study Of The Dynamical Dipole Mode In Heavy-ion Collision Via The Isospin-dependent Boltzmann-Uehling-Uhlenbeck (IBUU) Model

Giant resonance is one of hot spots in nuclear research. This study focuses ona new giant resonance which is dynamical dipole mode in heavy-ion reaction. Ourwork contain three part: symmetry energy dependence of the dynamical dipolemode, systematic study of dynamical dipole mode and infuence of neutron skin.First, we make a particular on both experimental and theoretical study.The isospin asymmetry of incident channel lead to the dynamical dipole mode inmedium and low energy reactions.Then, under the framework of IBUU model, we use a bremsstrahlung ap-proach to extract the γ spectrum and angular distribution of this prompt photonemission. We import a new form of the symmetry potential which dependentson the density of nucleon. By investigating16MeV/n36Ar+96Zr reaction, wecompare the calculated yield and angular distribution with the experimental da-ta. The results show that the dynamical dipole mode has a strong dependence onthe symmetry energy at subsaturation densities, and the soft symmetry energyis found to describe the data reasonably well.After, We investigate the dependence of centroid energy and strength ofthe γ spectrum on beam energy, N/Z ratio and mass asymmetry. Our resultsdemonstrate that the total emission probability of the dynamical dipole modehas a strong dependence on beam energy and charge asymmetry in the entrancechannel, beside on mass asymmetry. The central energy of this pre-equilibriumdipole oscillation is more sensitive to the beam energy and mass asymmetry thanthe case of charge asymmetry. And just the beam energy has an infuence on theanisotropy of the prompt photon radiation. But, almost, all of the features aresensitive to the impact parameters. So, this work indicates that detailed study ofdynamical dipole radiation can be used as a probe to extract information on theearly stage of charge-asymmetric heavy-ion collisions around the normal nucleardensity.Last, using the droplet model, we carry out diferent neutron skins in IBUU model. The results produced by diferent neutron skins show there are so manyfactors afected the γ spectrum and angular distribution of dynamical dipoleradiation. But the prompt nucleon emission would become dominant only whenthere is a huge neutron skin.