ON ANGULAR-MOMENTUM AND PARITY DEPENDENCE OF NUCLEAR-LEVEL DENSITIES IN A SIMPLE RANDOM SAMPLING APPROACH

Based on simple random sampling (SRS), we propose a Monte Carlo method for faster computation of the smoothed part of the density of nuclear states, To test the applicability of the SRS approach we study in thi s framework the excitation energy (E), angular momentum (J) and parity dependence of nuclear level densities for an independent particle sys tem. As an illustrative example, we consider a pf-shell nucleus, Cr-48 . It is found that the values of a few lower order moments for the sta te density I(E) calculated using SRS and combinatorial (or direct coun ting) methods are almost the same and a locally smoothed part of the s tate density can be constructed using these moments in a univariate Ed geworth expansion, We calculate the energy dependent spin-cutoff facto r and parity asymmetry and find that for both cases the SRS approach w orks quite well. We use the SRS moments to construct different forms o f the bivariate distribution for I(E, M) (M is the z-component of J) n amely (a) a bivariate Edgeworth expansion, (b) a product of the univar iate Edgeworth expansion (I(E)) and a Gaussian form for conditional M distribution I(M\E) and (c) a product of the univariate Edgeworth expa nsions for both I(E) and I(M\E) and compare the resulting fixed-J leve l density I-l(E, J) with the corresponding combinatorial results.