Coexistence of chiral symmetry and pseudospin symmetry in one nucleus: triplet bands in ¹⁰⁵Ag

The nearly degenerate triplet bands with the $\pi g_{9/2}^{-1}\otimes \nu h_{11/2}(g_{7/2}^{-1},d_{5/2}^{-1})$ configuration in ¹⁰⁵Ag are studied via the relativistic mean-field (RMF) theory and the multiparticle plus rotor model (MPRM). The configuration-fixed constrained triaxial RMF calculations exhibit pseudospin symmetry in single-particle spectra and triaxial shape coexistence. The experimental excitation energies and electromagnetic transition probabilities for the triplet bands are well reproduced by the MPRM calculations. The first and second lowest energy bands of the triplet bands are interpreted as pseudospin doublet bands, and the second and third bands are interpreted as chiral doublet bands. The chiral doublet bands show the same phase in the B(M1)/B(E2) staggering, while the pseudospin doublet bands hold the opposite phase. Such triplet bands in ¹⁰⁵Ag provide the first example for the coexistence of chiral symmetry and pseudospin symmetry in one single nucleus. (paper)