Emission temperatures from the decay of particle unstable complex nuclei

Abstract

The relative populations of particle-unstable states of intermediate-mass fragments were measured for the ${}_{}{}^{14}{}_{}{}^{}\mathrm{N}$+Ag reaction at E/A=35 MeV with a position-sensitive hodoscope. These measurements were compared to the predictions of statistical calculations which include the sequential decay of heavier particle unstable nuclei. The best overall agreement between the calculated and measured excited-state populations was obtained with calculations which assume emission temperatures of about 3–4 MeV for the primary distributions of the particle unstable intermediate-mass fragments. However, a detailed comparison between calculated and measured excited state populations assuming ${\mathit{T}}_{\mathrm{em}}$=4 MeV reveals significant discrepancies for about one-third to one-half of the measured quantities. Calculations that include rotational effects do not satisfactorily account for this discrepancy. These results suggest the possibility of a breakdown in the assumption of local thermal equilibrium at freezeout.