18967637
Mononuclear caloric curve in a mean field model
A mean field model is used to investigate if a plateau in caloric curve can be reached in mononuclear configuration. In the model the configuration will break up into many pieces as the plateau is approached.
2820708
Transverse momenta, nuclear equation of state, and momentum-dependent interactions in heavy-ion collisions.
We investigate the generation of transverse momentum in high-energy heavy-ion collisions and its relation to the nuclear equation of state. We find that streamer chamber data can be fitted by Boltzmann-Uehling-Uhlenbeck calculations with a momentum-dependent potential that closely models realistic nuclear matter interactions and yields an equation of state with {ital K}=215 MeV.
121836312
Excluded volume in nuclear fragmentation
14927510
A Transport Model for Nuclear Reactions Induced by Radioactive Beams
Major ingredients of an isospin and momentum dependent transport model for nuclear reactions induced by radioactive beams are outlined. Within the IBUU04 version of this model we study several experimental probes of the equation of state of neutron‐rich matter, especially the density dependence of the nuclear symmetry energy. Comparing with the recent experimental data from NSCL/MSU on isospin diffusion, we found a nuclear symmetry energy of Esym(ρ) ≈ 31.6(ρ/ρ0)1.05 at subnormal densities. Predictions on several observables sensitive to the density dependence of the symmetry energy at supranormal densities accessible at GSI and the planned Rare Isotope Accelerator (RIA) are also made.
16308546
First Order Phase Transition in Intermediate-Energy Heavy Ion Collisions
We model the disassembly of an excited nuclear system formed as a result of a heavy ion collision. We find that, as the beam energy in central collisions in varied, the dissociating system crosses a liquid-gas coexistence curve, resulting in a first-order phase transition. Accessible experimental signatures are identified: a peak in specific heat, a power-law yield for composites, and a maximum in the second moment of the yield distribution.
119186084
Bimodality and Coulomb effects with a canonical thermodynamic model
Abstract The effect of the Coulomb interaction on the phase diagram of finite nuclei is studied within the Canonical Thermodynamic Model. If Coulomb effects are artificially switched off, this model shows a phenomenology consistent with the liquid–gas phase transition. The inclusion of Coulomb does not significantly affect the phase diagram but it drastically modifies the nature and order parameter of the transition. A clear understanding of the phenomenon can be achieved looking at the distribution of the largest fragment produced in each fragmentation event. Possible connections with experimental observations are outlined.
14295878
Instantons and surface tension at a first-order transition
We study the dynamics of the first-order phase transition in the two-dimensional 15-state Potts model, both at and off equilibrium. We find that phase changes take place through nucleation in both cases, and finite volume effects are described well through an instanton computation. Thus a dynamical measurement of the surface tension is possible. We find that the order-disorder surface tension is compatible with perfect wetting. An accurate treatment of fluctuations about the instanton solution is seen to be of great importance.
16462004
DIMENSIONAL REDUCTION AND SCREENING MASSES IN PURE GAUGE THEORIES AT FINITE TEMPERATURE
Abstract We studied screening masses in the equilibrium thermodynamics of SU (2) and SU (3) pure gauge theories on the lattice. At a temperature of 2 T c we found strong evidence for dimensional reduction in the non-perturbative spectrum of screening masses. Mass ratios in the high-temperature SU (3) theory are consistent with those in the pure gauge theory in three dimensions. At the first-order SU (3) phase transition we report the first measurement of the true scalar screening mass.
121323084
Microscopic nucleon optical model potential at low energies
Nuclear optical model potentials at low energies have been computed utilizing the two (Micro I and Micro II) versions of the microscopic optical model of Jeukenne et al. A comparison has been made of the experimental nucleon-nucleus interaction data for E<10 MeV with the theoretical predictions obtained using the microscopic optical model.
122805550
Studies of the energy spectrum and composition of the primary cosmic rays at 100?1000 TeV from the GRAPES-3 experiment
The composition and energy spectrum of primary cosmic rays (PCRs) are the only observables at high energies to study the nature of sources accelerating PCRs to �1000 TeV. These observables have been directly measured up to ∼300 TeV with detectors aboard balloons and satellites. But measurements at >1000 TeV have to be obtained indirectly from ground-based observations of extensive air showers. However, their interpretation relies on an inadequate knowledge of hadronic interactions at �1000 TeV. The GRAPES-3 experiment is designed to operate at �30 TeV providing a sizable overlap in energy with direct measurements, enabling the selection of a suitable model of hadronic interactions at ∼1000 TeV. We present salient features of GRAPES-3 including details of muon multiplicity distributions observed with a 560 m 2 detector as a function of shower size from an analysis of data of 545 days. These distributions were compared with expectations from Monte Carlo simulations, using some of the hadronic interaction generators in CORSIKA, to deduce energy spectra of five nuclear groups in the 100–1000 TeV region. A comparison of GRAPES-3 results with direct measurements indicates that SIBYLL provides a good description of hadronic interactions for interpreting our data. These measurements extend energy spectra and composition of PCRs that is consistent with extrapolation of direct measurements. (Some figures may appear in colour only in the online journal)
120871108
Can charge correlations be used to signal the formation of a quark-gluon plasma?
We investigate short-range charge anticorrelations in nucleus-nucleus collisions whose suppresion could signal the presence of a quark-gluon plasma. We compute the charge correlations under some minimal assumptions about model parameters, and find that the results are not very sensitive to different parameters of the model.