Study Of Microscopic Optical Potential On Nucleus By Brueckner-Hartree-Fock Theory

Recently,the non-relativistic Brueckner-Hartree-Fock(BHF)theory has gotten great successful in reproducing the empirical properties of symmetric nuclear matter at saturation density by taking into account the contribution of three-body force,meanwhile,the isospin splitting of nucleon effective mass,the behavior of density dependence of symmetry energy and the nucleon self-energy in asymmetric nuclear matter have been properly described by BHF calculations.It is also very interesting to explore the optical potential of nuclear system based on the BHF calculations.Firstly,we have calculated the nucleon self-energy in symmetric and asymmetric nuclear matter within BHF by excluding and including the contribution of three-body force,the adopted bare nucleon-nucleon interaction is Av18.We find that the effect of three-body force on nucleon self-energy depends on the channel,in some channels it gives an attractive contribution,in other channels it gives a repulsive contribution.The three-body force has almost no contribution in the low-density region,but the difference of nucleon self-energy in the cases of with and without three-body force is becoming larger with increasing the density.Then we obtained the optical potential in nuclear matter by parameterizing the nucleon self-energy within different incident particle energies and a wide range of density.Within the local density approximation,we can get the optical potential for finite nuclei 160?40Ca?90Zr and 208Pb with different incident particle energies,and obtained microscopic optical potentials are compared with the phenomenological Koning-Delaroche potentials.We find that the microscopic optical potentials are deeper than the corresponding phenomenological Koning-Delaroche potentials in the interior of all nuclei,and they have very different behaviors in the surface of finite nuclei.Moreover,we have investigated the elastic scattering reaction induced by neutron or proton,especially we calculated the elastic scattering differential cross section d6/dQ.the analyzing power Ay and the spin-rotation function Q for selected finite nuclei by using obtained microscopic optical potentials.The calculated results are also compared with those given by using phenomenological Koning-Delaroche potentials and experimental data.Totally,for the cross sections with energy less than 50 MeV,our results agree basically with the experimental data;for those cross sections with energy larger than 50 MeV.they are described very well in small angle,big discrepancies are found in large angle,the calculated cross sections are larger than the experimental data.For the analyzing power Ay and the spin-rotation function Q.the calculated results by using microscopic optical potentials are in good agreement with experimental data for nuclei O and Ca,but for Zr and Pb,the results have similar behavior with the experimental data,but the obtained precision is not good as we expected.Finally we find that the microscopic optical potentials can basically describe the experimental data in elastic scattering differential cross section d?/d?the analyzing power Ay.and the spin-rotation function Q,the agreement cannot be compared to the case obtained with phenomenological Koning-Delaroche potential.Those results indicate that our microscopic optical potentials have the main properties of optical potentials,they are obtained within microscopic many-body theory,and have no adjusted parameters,the advantage is that our potential can be used to describe the reaction of unstable nuclei.For the future,we can improve the BHF results by taking into account the contribution of dynamical process in nuclear system,which is called beyond mean field calculations.