Angular momentum dependence of GDR widths and level densities in hot nuclei

Using static path approximation we have studied the angular momentum dependence of widths and shapes of GDR (giant dipole resonance) built on hot rotating nuclei. We find that the widths depend strongly on angular momentum. At higher values of angular momentum the GDR widths become almost independent of temperature. Also, we analyze in detail the applicability of angular momentum dependence in the Bethe's formula for nuclear level density. We find that Bethe's formula which is based on spin-cut-off approximation works well at lower values of angular momentum and at higher angular momentum it overestimates the values of level density. We have demonstrated that the Bethe's formula can be significantly improved by including the effect of a few higher-order moments of M-distribution (M is the z component of total angular momentum). (author)