Damping of hot giant dipole resonance due to complex configuration mixing

An approach is presented to study the width of the giant dipole resonance (GDR) at non-zero temperature T, which includes all forward-going processes up to two-phonon ones. Calculations are performed in 120Sn and 208Pb. An overall agreement between theory and experiment is found for the GDR width and shape. The total width of the GDR due to coupling of the GDR phonon to all ph, pp and hh configurations increases sharply as T increases up to T∼3 MeV and saturates at T∼4–6 MeV. The quantal width ΓQ due to coupling to ph configurations decreases with increasing T. It is almost independent of T if the contribution of two-phonon processes at T≠ 0 is omitted.