Measurements of evaporation residue cross-sections and evaporation residue-gated γ\gamma-ray fold distributions for 32^{32}S+154^{154}Sm system

Evaporation Residue (ER) cross-sections and ER-gated $\gamma$-ray fold distributions are measured for the $^{32}$S + $^{154}$Sm nuclear reaction above the Coulomb barrier at six different beam energies from 148 to 191 MeV. $\gamma$-ray multiplicities and spin distributions are extracted from the ER-gated fold distributions. The ER cross-sections measured in the present work are found to be much higher than what was reported in a previous work using a very different target-projectile ($^{48}$Ti + $^{138}$Ba) combination, leading to the same compound nucleus $^{186}$Pt, with much less mass asymmetry in the entrance channel than the present reaction. This clearly demonstrates the effect of the entrance channel on ER production cross-section. The ER cross-sections measured in the present work are compared with the results of both the statistical model calculations and the dynamical model calculations. Statistical model calculations have been performed to generate a range of parameter space for both the barrier height and Kramers' viscosity parameter over which the ER cross-section data can be reproduced. The calculations performed using the dinuclear system (DNS) model reproduce the data considering both complete and incomplete fusion processes. DNS calculations indicate the need for the inclusion of incomplete fusion channel at higher energies to reproduce the ER cross-sections.Comment: 13 pages, 18 figure

High spin structure in

High spin states of 130,131Ba have been investigated via fusion evaporation reactions 122Sn(13C,4n)131Ba and 122Sn(13C, 5n)130Ba at $E_{beam}=65$ MeV. The level schemes of 130,131Ba have been extended by placing several new $\gamma$ transitions. A few interband transitions connecting two negative-parity bands, which are the experimental fingerprints of signature partners, have been established in 130Ba. Spin and parity of a side band have been assigned in 131Ba and this dipole band is proposed to have a three-quasiparticle configuration, $\nu h_{11/2}\otimes\pi h_{11/2}\otimes\pi g_{7/2}$ . The observed band structures and nuclear shape evolution as a function of the angular momentum have been discussed in the light of Total-Routhian-Surface calculations