Impact of magnetic field on giant dipole resonance of $^{40}$Ca using the EQMD model

By taking into account the magnetic field in the extended quantum molecular dynamics model (EQMD), we analyzed its effects on giant dipole resonance (GDR) by studying the responses and strengths of the dipole moments. The selected system is the $^{40}$Ca nucleus which is excited through the Coulomb interaction by $^{16}$O. Particle acceleration term in Li\'enard-Wiechert potential is discussed which, however, has small impact on magnetic field. The peak energy, strength and width of GDR, temperature, and angular momentum of $^{40}$Ca as a function of beam energy are investigated. It is found that the magnetic field enhances the peak energy, strength and width of GDR which is not only due to the temperature effects but also due to the enhancement of the angular momentum of nucleus. At beam energy {E} $>$ 200 MeV/nucleon, magnetic field maintains a constant value for the strength of GDR. The work sheds light on examining important roles of the magnetic field on nuclear structure in low-intermediate energy heavy-ion collisions.
Comment: 9 pages, 6 figures