Pairing phase transition in an odd–even hot ⁶⁹Zn nucleus

The pairing phase transition in an odd–even hot-rotating 69 Zn nucleus has been investigated by using the reported nuclear level density (NLD) data, which were experimentally extracted from the γ -gated particle spectra. The experimental NLDs have been compared with those obtained within the microscopic exact pairing plus independent-particle model at finite temperature (EP+IPM) along with the results of other microscopic calculations such as the Hartree–Fock BCS (HFBCS) and Hartree–Fock–Bogoliubov plus combinational (HFBC) methods. It is found that the experimental NLDs can be well described by the EP+IPM using the recommended quadrupole deformation parameter β 2 = −0.164. Intriguingly, the heat capacity calculated using the EP+IPM NLD exhibits a sharp S -shape, which is not expected in such odd–even hot or hot-rotating system as reported earlier. Changing the deformation parameter β 2 does not change much this S -shape. However, increasing or decreasing the pairing gaps could enhance or destroy the S -shaped heat capacity. Therefore, the S -shaped heat capacity in odd–even 69 Zn nucleus is explained due to the deformation-induced pairing correlation.