Angular distribution of electromagnetic bremsstrahlung from heavy-ion collisions at intermediate energies

Abstract

Recently measured spectra of hard photons emitted in collisions between two heavy ions at bombarding energies as low as 35 MeV/n have been reported by Alamanos et al. to show dipole-like angular patterns. In a schematic calculation it will become obvious that these photons may be interpreted as coherent bremsstrahlung arising from collisions with non-zero impact parameters where the axial symmetry, which usually leads to cancellation of the dipole contribution, is distorted.