Triplet states in Lead isotopes Tabassum Naz 1 , * Shakeb Ahmad 2 , † and H. Abusara 3‡ 1 Department Of Physics, Aligarh Muslim University, Aligarh - 202002, India 2 Physics Section, Women’s College, Aligarh Muslim University, Aligarh - 202002, India and 3 Department Of Physics, BirZeit University, Ramallah, Palestine Introduction In atomic nuclei with even numbers of neu- trons and protons, the low-lying excitation spectrum is generally formed by nucleon pair breaking and nuclear vibrations or rotations. However, for certain numbers of protons and neutrons, a subtle rearrangement of only a few nucleons among the orbitals at the Fermi sur- face can result in microcopic shape change. In mean-field models, the 0 + states observed at low energies are associated with coexisting en- ergy minima which appear for different values of the axial quadrupole moment. The ener- gies of different shape configuratons are cal- culated using a nuclear potential with ener- gies of the single paricle orbitals depending on the deformation. In the context of the nu- clear shell model, the emergence of low-lying excited 0 + states is traced back to the pro- ton particle-hole excitation across the Z = 82 closed shell. The residual interaction between protons and neutrons is enhanced due to this cross-shell excitation, resulting in the lowering of the excited 0 + states. In the vicinity of the N = 104 mid-shell, the effect is strengthened and has a stronger impact on excitation en- ergies [1]. The fact that this situation takes place in several lead isotopes makes this re- gion more attractive to understand the phe- nomenon of coexistence experimentally and theoretically [2, 3]. We have done calculations for 184-190 Pb using the Relativistic Hartree Bogoliubov (RHB) formalism [4] with finite- range (DD-ME2 and NL3*) and zero-range (DD-PC1) interaction. * Electronic address: tabasumnaz321@gmail.com † Electronic address: physics.sh@gmail.com ‡ Electronic address: habusara@birzeit.edu -0.4 -0.2 0 0.2 0.4 0.6 Deformation [β 20 ] 0 1 2 3 4 5 6 Energy [MeV] 184 Pb 186 Pb 188 Pb 190 Pb DD-ME2 FIG. 1: The potential energy surface of 184-190 Pb. FIG. 2: The potential energy surfaces of 184-190 Pb isotopes. The color scale shown at the right has the unit of MeV, and scaled such that the ground state has a zero MeV energy Results and Discussion The energy surface as a function of quadrupole deformation parameters is ob- tained by solving the RHB equation with Proceedings of the DAE Symp. on Nucl. Phys. 62 (2017) 70 Available online at www.sympnp.org/proceedings