The pairing correlations in hot nuclei 162Dy are investigated in terms
of the thermodynamical properties by covariant density functional theory. The
heat capacities CV​ are evaluated in the canonical ensemble theory and the
paring correlations are treated by a shell-model-like approach, in which the
particle number is conserved exactly. A S-shaped heat capacity curve, which
agrees qualitatively with the experimental data, has been obtained and analyzed
in details. It is found that the one-pair-broken states play crucial roles in
the appearance of the S shape of the heat capacity curve. Moreover, due to the
effect of the particle-number conservation, the pairing gap varies smoothly
with the temperature, which indicates a gradual transition from the superfluid
to the normal state.Comment: 13 pages, 4 figure
