Charged particles in coincidence with superdeformed states: A test of the compound nucleus decay at large angular momenta

The reaction 37Cl+120Sn at 187 MeV bombarding energy has been investigated in a coincidence experiment between charged particles and γ-rays at the GASP spectrometer. The population of the superdeformed (SD) band of 152Dy has been studied in the p4n and d3n channels. Alpha particle spectra in coincidence both with normal deformed (ND) and SD bands of 150Tb have been measured. A clear difference is observed between the two spectra, that in coincidence with the SD states being shifted to lower energies. This effect is understood in terms of different angular momentum regions from which the ND and SD states originate. The standard statistical model fails to describe the angular momentum dependence of the alpha particle energies. The use of statistical model in the region where the fission-evaporation competition is strongly affected by dynamical effects is discussed.