The population of deformed bands in $^{48}$Cr by emission of $^{8}$Be from the $^{32}$S + $^{24}$Mg reaction

Abstract

Using particle-$γ$ coincidences we have studied the population of final states after the emission of 2 $α$-particles and of $^{8}$Be in nuclei formed in $^{32}$S+$^{24}$Mg reactions at an energy of $\textrm{E}_{\rm L}(^{32}\textrm{S}) = 130 {\rm MeV}$. The data were obtained in a setup consisting of the GASP $γ$-ray detection array and the multidetector array ISIS. Particle identification is obtained from the $Δ$E and E signals of the ISIS silicon detector telescopes, the $^{8}$Be being identified by the instantaneous pile up of the $Δ$E and E pulses. $γ$-ray decays of the $^{48}$Cr nucleus are identified with coincidences set on 2 $α$-particles and on $^{8}$Be. Some transitions of the side-band with $K^π=4^{-}$ show stronger population for $^{8}$Be emission relative to that of 2 $α$-particles (by a factor $1.5-1.8$). This observation is interpreted as due to an enhanced emission of $^{8}$Be into a more deformed nucleus. Calculations based on the extended Hauser-Feshbach compound decay formalism confirm this observation quantitatively.

17 pages, 9 figures accepted for publication in J. Phys. G