Evolution from γ -soft to stable triaxiality in Nd136 as a prerequisite of chirality

Abstract

The level structure of 136 Nd has been investigated using the 100 Mo(40 Ar, 4n) reaction and the JUROGAM II+RITU+GREAT setup. The level scheme has been extended significantly. Many new bands have been identified both at low and high spin, among which are five nearly degenerate bands interpreted as chiral partners. Excitation energies, spins, and parities of the previously known bands are revised and firmly established, and some previously known bands have been revised. Configurations are assigned to the observed bands based on cranked Nilsson-Strutinsky calculations. The band structure of 136 Nd is now clarified and the various types of single-particle and collective excitations are well understood.

Lifetime of the recently identified 10+ isomeric state at 3279 keV in the Nd136 nucleus

“…In particular, the energy competition between the high-K and collectively rotating, low-K, aligned configurations depends on the actual γ -dependent mixing. The 10 + state at 3279 keV could be a configuration with two aligned h 11/2 neutrons at a negative γ , as suggested by cranking calculations without pairing in the recent work [12] (the band built on this state is referred to as L7 there). Then it would be strongly K mixed and one could argue that a more sophisti- cated model which preserves angular momentum should be used for its description; see the study [22] in this context.…”

“…These lowest-members of the h 11/2 intruder subshells lie much closer (less than 0. The measurement of the magnetic moment of the 10 + state at 3296 keV [12] indicates its aligned proton pair structure, which, together with the analysis of alignment in various bands [1], suggests that h 11/2 protons align before the neutrons do.…”

“…Previous in-beam spectroscopic studies of low-and medium-spin states in 136 Nd have developed the level scheme of this nucleus, as reported by Paul et al [1] using the 116 Cd( 24 Mg, 4n) 136 Nd reaction at bombarding energies of 106 and 111 MeV; by C.M. Petrache et al [4][5][6] and S. Perries et al [7] using the 110 Pd( 30 Si, 4n) 136 Nd reaction at 130 MeV; by Billowes [8] using the 110 Pd( 30 Si, 4n) 136 Nd reaction at 125 MeV; by Saito et al [9] in relativistic Coulomb excitation; by Mergel et al [10] using the 125 Te( 16 O, 5n) 136 Nd reaction at 100 MeV; by S. Mukhopadhyay et al [11] using the 100 Mo( 40 Ar, 4n) 136 Nd reaction at 175 MeV; and by Lv et al [12].…”

Diversity of shapes and rotations in the γ-soft 130Ba nucleus: First observation of a t-band in the A = 130 mass region

“…The first important result of the present work is the observation of the odd-spin bands S1 and S2o , of the even-spin bands S1 and S2o. There is very scarce experimental information on such odd-spin states decaying to the states of the S-bands, typically only a few levels being observed [26][27][28][29][30][31][32]. Their interpretation is often handwaving, invoking the γ-band built on the S-bands, or is completely missing.…”

Highly deformed bands in Nd nuclei: New results and consistent interpretation within the cranked Nilsson-Strutinsky formalism

“…The present work was triggered by the new results obtained from a high-statistics JUROGAM II experiment [44][45][46][47][48][49], which allowed us to extend the known HD bands of 136 Nd and 137 Nd at lower and higher spins and to identify three new HD bands in 136 Nd. The HD bands of 134 Nd, 136 Nd, and 137 Nd nuclei are interpreted in the framework of the cranked Nilsson-Strutinsky (CNS) model [50][51][52].…”