Dynamical fluctuations in fragmentation reactions in a Boltzmann–Langevin approach

Abstract

Based on the isospin-dependent Boltzmann–Langevin model, the dynamical fluctuations in the fragmentation reaction of 112Sn+112Sn are investigated. The quadrupole moment and octupole moment with zero magnetic quantum number have large fluctuations in the early time of the collisions. The dynamical fluctuations in momentum space show a strong dependence on the incident energy. The effects of using different fluctuations on the fragment cross sections are also studied in the fragmentation reactions. The results by using Q 20 + Q 30 fluctuation have a better agreement with the experimental data. Calculations using Q 20 + Q 30 fluctuation produce more proton-rich and neutron-rich nuclei than those using Q 20 fluctuation only. Besides, the difference between the production cross sections of fragments calculated by using Q 20 and Q 20 + Q 30 fluctuations is larger in the vicinity of the projectile. These results present that the dynamical fluctuations may affect the whole dynamical process of fragmentation reactions including the production of fragments, due to the nonlinear nature of the Boltzmann–Langevin equation.