Towards limiting temperatures in nuclei: The behavior of collective motion

Abstract
Gamma rays emitted from hot nuclei with mass around 115 and excitation energies between 350 and 500 MeV, formed in the Ar36 + Zr90 reaction at 27 MeV/nucleon have been measured. The γ-ray yield from the decay of the giant dipole resonance in these nuclei remains constant over the excitation energy range studied. This quenching of the γ multiplicity cannot be explained by a continuous increase with temperature of the width of the resonance. Better agreement with the data is obtained by assuming a cutoff of γ emission from the resonance above an excitation energy of 250 MeV. The existing data do not show entrance channel effects.
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