Parity dependence of nuclear level density

The knowledge parity dependent nuclear level density ρ(E, J, π) is very essential in low energy nuclear physics as it is used to evaluate nuclear cross-sections in nuclear reaction calculations. At low excitation energies, astrophysical reaction rates are sensitive to the parity distribution. However, the information of level density is confined to a rather small region of excitation energy, angular momentum and parity. Several theoretical studies have shown that at low energies there is a dominance of one type of parity and near the particle separation energy that parity ratio only approaches to an equal distribution. An accurate determination of nuclear level density and its dependence on mass number, excitation energy, angular momentum, parity, etc. is necessary for precise prediction of cross sections using the statistical models. In the present work, an absolute asymmetry parameter is used to determine the level density of negative as well as for positive parity states by using sand p- wave (D₀ and D₁) neutron level spacing. The systematic are investigated from 23 < A < 238 and compared to the pattern found in previous investigations. The present analysis also provides useful information on various resonance parameters at different nuclear mass regions with results that support the original conclusions. (author)