Multiple chiral doublets in four-j shells particle rotor model: Five possible chiral doublets in 60136Nd76

Abstract

A particle rotor model, which couples nucleons in four single-j shells to a triaxial rotor core, is developed to investigate the five pairs of nearly degenerate doublet bands recently reported in the even-even nucleus 136 Nd. The experimental energy spectra and available B(M 1)/B(E2) values are successfully reproduced. The angular momentum geometries of the valence nucleons and the core support the chiral rotation interpretations not only for the previously reported chiral doublet, but also for the other four candidates. Hence, 136 Nd is the first even-even candidate nucleus in which the multiple chiral doublets exist. Five pairs of chiral doublet bands in a single nucleus is also a new record in the study of nuclear chirality. * Electronic address: mengj@pku.edu.cn

Chirality of Nd135 reexamined: Evidence for multiple chiral doublet bands

“…In most nuclei only one chiral doublet was observed, but in a limited subset of chiral nuclei two or more chiral doublets were observed ( 78 Br [20], 103 Rh [12], 105 Rh [13], 133 Ce [9], 136 Nd [18], 195 Tl [21], and possibly 107 Ag [22]), exhibiting the exotic phenomenon of multiple chiral doublet bands (MχD) [23][24][25][26][27][28][29][30][31]. In the even-even nucleus 136 Nd, the record of five nearly degenerate band pairs were identified, with properties in agreement with chiral interpretation within the tilted axis cranking constrained density functional theory (TAC-CDFT) framework [18], which were also successfully described in detail as chiral doublets in the framework of the multi-j shell particle rotor model (PRM) [31]. An alternative formalism predicting a new type of chiralitiy, different from that existing in odd-odd and odd-even nuclei, based on the generalized coherent state model, was also proposed and applied to the even-even nucleus 138 Nd [32,33].…”

Identification of high- K rotation in Ba130 : Testing the consistency of electromagnetic observables

“…It is also useful to compare the data with particle-rotor model (PRM) calculations [37,38] and constrained covariant density functional theory [39] to determine the deformation parameters. For the K π = 8 − band head in 130 Ba, the deformations obtained are β 2 = 0.23 and γ = 12 • using PC-PK1 interaction [40], which compare with β 2 = 0.18 and γ = 6 • from earlier total-Routhian-surface calculations [20].…”

Possible chiral doublets in 60Ni

“…During the process of investigating nuclear chirality, exploring novel chiral phenomena and searching for new chiral candidates are the two fundamental goals all the time. For the former, e.g., the multiple chiral doublets (MχD) phenomenon, i.e., having multiple pairs of chiral doublet bands in a single nucleus, was theoretically predicted and explored by the state-of-art covariant density functional theory (CDFT) [31][32][33][34][35][36][37] and observed in 133 Ce [38], 103 Rh [39], 78 Br [40], 136 Nd [41,42], and 195 Tl [43]. These observations confirm the existence of triaxial shapes coexistence [31,38,41,43], and reveal the stability of chiral geometry against the increasing of intrinsic excitation energy [39,[44][45][46][47] and octupole correlations [40].…”