H. Xi

Isospin diffusion observables in heavy-ion reactions

Collisions of {sup 112}Sn and {sup 124}Sn nuclei, which differ in their isospin asymmetry, provide information about the rate of isospin diffusion and equilibration. Although several different probes can provide accurate diffusion measurements, the ratios of the mirror nuclei may be the simplest and most promising one. Ratios of the mass seven mirror nuclei yields are analyzed to show the rapidity, transverse momentum, and impact parameter dependence of isospin diffusion.

Thermal excitation of heavy nuclei with 5–15 GeV/c antiproton, proton and pion beams

Abstract Excitation-energy distributions have been derived from measurements of 5.0–14.6 GeV/c antiproton, proton and pion reactions with 197 Au target nuclei, using the ISiS 4 π detector array. The maximum probability for producing high excitation-energy events is found for the 8 GeV/c antiproton beam relative to other hadrons, 3 He and p beams from LEAR. For protons and pions, the excitation-energy distributions are nearly independent of hadron type and beam momentum above about 8 GeV/c. The excitation energy enhancement for p beams and the saturation effect are qualitatively consistent with intranuclear cascade code predictions. For all systems studied, maximum cluster sizes are observed for residues with E ∗ /A∼6 MeV.

Fragment production in noncentral collisions of intermediate-energy heavy ions

The defining characteristics of fragment emission resulting from the non-central collision of 114Cd ions with 92Mo target nuclei at E/A = 50 MeV are presented. Charge correlations and average relative velocities for mid-velocity fragment emission exhibit significant differences when compared to standard statistical decay. These differences associated with similar velocity dissipation are indicative of the influence of the entrance channel dynamics on the fragment production process.

Nuclear temperature measurements with helium isotopes

Abstract Temperatures extracted with the family of ( 3 He , 4 He ) isotope ratio thermometers, THe, have been studied and cross-checked with temperatures, T( 4 He ∗ ) constructed from excited and ground state populations of 4 He . Empirical correction factors provide baseline corrections for sequential decay effects for THe T( 4 He ∗ ) should agree.

Isotope yields from central Sn-112, Sn-124 + Sn-112, Sn-124 collisions, dynamical emission?

Isotopic yields for light particles and intermediate mass fragments have been measured for central 112Sn +112Sn, 112Sn+124Sn, 124Sn+112Sn, and124Sn+124Sn collisions atE/A=50 MeV and compared with predictions of stochastic mean field calculations. These calculations predict a sensitivity of the isotopic distributions to the density dependence of the asymmetry term of the nuclear equation of state. However, the secondary decay of the excited fragments modifies significantly the primary isotopic distributions and these modifications are rather sensitive to theoretical uncertainties in the excitation energies of the hot fragments. The predicted final isotope distributions are narrower than the experimental data and the sensitivity of the predicted yields to the density dependence of the asymmetry term is reduced.

Isospin observables from fragment energy spectra

The energy spectra of light charged particles and intermediate mass fragments from

Isotope yields from central 112,124Sn+112,124Sn collisions: Dynamical emission?

{}^{112}\mathrm{Sn}+{}^{112}\mathrm{Sn}

Excitation and decay of projectilelike fragments formed in dissipative peripheral collisions at intermediate energies

and

MULTIFRAGMENTATION : THERMAL VS. DYNAMIC EFFECTS

{}^{124}\mathrm{Sn}+{}^{124}\mathrm{Sn}

Comparison of midvelocity fragment formation with projectilelike decay

collisions at an incident energy of