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Suppression of multiplicity fluctuations has been observed for three light fermions (protons, tritons and 3He) in the multifragmentation of reconstructed hot quasi-projectiles produced in collisions of 32S (45 MeV/nucleon) with 112Sn. This suppression, predicted by recent calculations, is attributed to Pauli blocking and has also been observed in experiments with trapped Fermi gases. Experimental results on nuclear temperature and density employing a quantal approach based on momentum and multiplicity fluctuations are also presented. The extracted temperatures show a noticeable reduction when compared to a similarly derived classical method. This reduction in temperature is in agreement with previous predictions indicating that classically derived methods overpredict nuclear temperature as they do not take into account the Fermi motion of the nucleons. The present results underline the role of quantum statistics in nuclear disassembly and suggest the need for proper quantum treatment when dealing with the thermodynamic properties of fragmenting heavy ions. [ABSTRACT FROM AUTHOR]

The thermodynamics of excited nuclear systems allows the exploration of a phase transition in a two-component quantum mixture. Temperatures and densities are derived from quantum fluctuations of fermions. The pressures are determined from the grand partition function of Fisher's model. Critical scaling of observables is found for the first time for fragmenting systems which differ in neutron to proton concentrations thus constraining the equation of state (EOS) of asymmetric nuclear material. The derived critical exponent, β = 0.35 ±0.01, belongs to the liquid-gas universality class. The critical compressibility factor Pc/ρcTc increases with increasing neutron concentration, which could be due to finite-size and/or Coulomb effects. [ABSTRACT FROM AUTHOR]

The production of fragments from a broad range of reconstructed quasiprojectiles obtained in the interaction of 32S (45 MeV/nucleon) with 112Sn was studied. A good description of the experimental data on the multifragmentation of these light quasi-projectiles with a model framework based on deep inelastic transfer followed by SMM(statistical multi fragmentation model)was obtained. The charge and mass distributions of the observed fragments show that the break-up of a given quasi-projectile source is highly correlated to its isospin composition. The sensitivity of the hot primary fragments to the symmetry energy was investigated in detail. It was found that for the present light systems (A~30), a good description of the experimental data on the charge distributions, the N/Z distributions and the isotopic distributions of the fragments is obtained by the SMMcalculations involving the standard (Csym = 25MeV), as well as, a reduced value of the symmetry energy (Csym = 8 MeV). However, the reduced value of the symmetry energy appears to provide a better description of the isotopic distributions in most of the cases. This is in agreement with an overall reduction of the symmetry energy of primary fragments indicated by a number of multifragmentation studies of heavier systems. [ABSTRACT FROM AUTHOR]