The effect of large angular momenta on multifragmentation of hot nuclei

Abstract

Abstract Multifragmentation of highly-excited nuclei with large angular momenta is analyzed as an example of microcanonical thermodynamics. The equipartition of the available phase space under the constraint of a given (large) angular momentum gives interesting new effects which cannot be studied in conventional thermodynamics. It is shown that momentum- and energy distributions of the fragments are considerably changed from the non-rotational case. Especially, a large slope parameter of the kinetic energy distribution is established which is up to ten times large than the thermodynamic temperature. This, commonly attributed to nonequilibrium effects, can be used to identify high angular momenta. In this way “nonthermal” collective motion of nuclear matter (flows) observed in some experiments in which one would not expect any compressions may be understood as fully equilibrized thermal motion under large angular momentum.