Signatures of transverse wobbling motion in Pm 139

Abstract

The negative parity structure in the Pm139 nucleus has been investigated through the Cd116 (P31, α4n) reaction at Elab=148MeV using the Indian National Gamma Array. The experimental B(E2)out/B(E2)in and B(M1)out/B(E2)in ratios along with the quasiparticle triaxial rotor model using the frozen alignment approximation calculations for the low-lying quadrupole bands QB1, QB2, QB3 and QB4 lead to the conclusion that the transverse wobbling structures for the first and second phonon may exist in Pm139. In addition, measured B(M1) and B(E2) rates for the dipole bands DB1 and DB2 agree with the shears mechanism with principal axis cranking model calculations. Thus, the existence of the magnetic rotational bands DB1 and DB2 after the first and second quasiparticle crossing support the origin of the quadrupole bands QB1, QB2, QB3, and QB4 from the wobbling excitation. © 2024 American Physical Society.