Deexcitation Energy of Superdeformed Secondary Minima as a Probe toDensity Dependence of Symmetry Energy

Deexcitation energies of superdeformed secondary minima of odd-odd Au and Tl isotopes are investigated with the relativistic mean field (RMF) model where the isoscalar-isovector coupling is included to change the symmetry energy. It is verified by the theoretical analysis and numerical results that the deexcitation energies of superdeformed secondary minima relative to the ground states in these heavy nuclei are sensitive to differences in thesymmetry energy. In particular, the linear correlation between the deexcitation energies of odd-odd Au and Tl isotopes and the neutronskin thickness in ²⁰⁸Pb is established. Moreover, explorationsare extended to superdeformed candidates of other mass regions. Itis found that the linear correlation can even be established betweenthe deexcitation energies and the symmetry pressure at subsaturationdensity. These indicate that deexcitation energies can serve as aprobe to the density dependence of the symmetry energy.