High spin states in57135La78

Abstract

High spin states in 135 La have been investigated using the 128 Te( 11 B,4n) 135 La reaction at a beam energy of 50.5 MeV using the Indian National Gamma Array (INGA). The level scheme has been confirmed and extended both for low and high spin states with the observation of several new transitions. The Directional Correlations of Oriented states (DCO) ratios and linear polarization measurements have been performed to assign spin-parity for most of the reported γ transitions. A new positive parity band has been observed and identified as a decoupled band ( I = 2). Two negative parity dipole bands ( I = 1) have been established and for one of the dipole bands the crossover E2 transitions have been identified for the first time. On the basis of the Tilted Axis Cranking (TAC) calculations, a three quasiparticle (qp) π (h 11/2 ) 1 ⊗ ν(h 11/2 ) −2 configuration and 5qp π (h 11/2 ) 1 (g 7/2 /d 5/2 ) 2 ⊗ ν(h 11/2 ) −2 configuration have been assigned to these two dipole bands. The comparison with experimental observables supports the configuration assignments for both the dipole bands.

Spectroscopy of135La

“…3, we have drawn the transitions assigned to band 8 differently than in Ref. [6], in agreement with our interpretation of the experimental results. The first important difference with respect to Ref.…”

“…[6]. All transitions were observed previously [5,6], but important differences with respect to the recently published results in Ref. [6] are observed and presented below.…”

“…In the present experiment we did not measure the DCO ratios and polarization asymmetries, therefore the spin-parity assignments are based on the data published in Ref. [6]. All transitions were observed previously [5,6], but important differences with respect to the recently published results in Ref.…”

“…[6], leading to spin-parity ( with either I = 2 E2 or I = 0 M1 character. It is assigned as a I = 0 transition in Ref.…”

“…The first important difference with respect to Ref. [6] concerns the transitions of band 8. The band-head spin and parity of band 8 are assigned (15/2 − ) on the basis of the DCO ratio (R DCO ) and the polarization asymmetry ( ) of the 380 keV transition towards the yrast 15/2 − state, which are 1.07(3) Q (the Q and D superscripts indicate the quadrupole or dipole nature of the gating transitions) and 0.19(2), respectively.…”