Many-particle correlations and Coulomb effects on temperatures from fragment momentum fluctuations
AbstractWe investigate correlations in the fragment momentum distribution owing to the propagation of fragments under the influence of their mutual Coulomb field after the breakup of an excited nuclear source. The magnitude of the effects on the nuclear temperatures obtained from such distributions is estimated with the help of a simple approach in which a charged fragment interacts with a homogeneous charged sphere. The results are used to correct the temperatures obtained from the asymptotic momentum distributions of fragments produced by a Monte Carlo simulation in which the system's configuration at breakup is provided by the canonical version of the statistical multifragmentation model. In a separate calculation, the dynamics of this many-particle charged system is followed in a molecular dynamics calculation until the fragments are far away from the breakup volume. The results suggest that, although the magnitude of the corrections is similar in both models, many-particle correlations present in the second approach are non-negligible and should be taken into account to minimize ambiguities in such studies.