Possible assignment of chiral twin bands inI188r

Abstract

High-spin states in the doubly-odd Z = 77 nucleus 188 Ir were populated in the 186 W͑ 7 Li,5n͒ reaction at 52 MeV. Two nearly degenerate ⌬I = 1 sequences with the same parity were established. Both bands have been assigned the h 9/2 i 13/2 configuration, based on the systematic behavior of these excitations in the Ir nuclei and on the measured values for the B͑M1͒ / B͑E2͒ ratios, and they are suggested as candidates for a chiral doublet.

Evidence for Octupole Correlations in Multiple Chiral Doublet Bands

“…Such chiral doublet bands were first observed in N ¼ 75 isotones [2]. So far, more than 30 experimental candidates have been reported in the A ∼ 80, 100, 130, and 190 mass regions [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20].Based on constrained triaxial covariant density functional theory (CDFT) calculations, it has been suggested that multiple chiral doublet (MχD) bands can exist in a single nucleus [21][22][23][24][25][26]. The theoretical prediction of MχD bands stimulated lots of experimental efforts [27][28][29][30][31].…”

“…Such chiral doublet bands were first observed in N ¼ 75 isotones [2]. So far, more than 30 experimental candidates have been reported in the A ∼ 80, 100, 130, and 190 mass regions [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20].…”

Multiple Chiral Doublet Bands of Identical Configuration inRh103

“…Such chiral doublet bands were first identified in four N = 75 isotones in 2001 [2]. So far, many chiral candidate nuclei have been reported experimentally in the A ∼ 80, 100, 130, and 190 mass regions [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21]. Besides the simplest chiral configurations composed of one unpaired proton and neutron, composite chiral configurations, containing more than one unpaired protons and/or neutrons, have also been observed in the odd-mass or even-even neighbors of the odd-odd chiral nuclei [10,18].…”

Revised and extended level scheme of the doubly-odd nucleusIr188

“…In a recent article, Balabanski et al presented the first extensive work about the high-spin structure of the doubly odd Z = 77 nucleus 188 Ir [1]. The level scheme proposed in that work comprises two regular bands as well as a number of irregularly spaced levels of single-particle structure.…”

“…In addition, we wanted to carefully check the entire level scheme because some of its aspects seemed to require further clarification. One example is the fact that of the four 16 − states observed within 186 keV the highest one collects nearly all the intensity flux, whereas the yrast state of this spin is only very weakly populated [1]. 188 Ir were populated using the reaction 186 W( 7 Li, 5n).…”