Triton-3He relative and differential flows and the high density behavior of nuclear symmetry energy

Using a transport model coupled with a phase-space coalescence after-burner we study the triton-3He relative and differential transverse flows in semi-central 132Sn+124Sn reactions at a beam energy of 400 MeV/nucleon. We find that the triton-3He pairs carry interesting information about the density dependence of the nuclear symmetry energy. The t-3He relative flow can be used as a particularly powerful probe of the high-density behavior of the nuclear symmetry energy.Comment: 6 pages, 2 figures, Proceeding of The International Workshop on Nuclear Dynamics in Heavy-Ion Reactions and the Symmetry Energ

Isospin dependence of nucleon emission and radial flow in heavy-ion collisions induced by high energy radioactive beams

Using an isospin- and momentum-dependent transport model we study the emission of free nucleons and the nuclear radial flow in central heavy-ion collisions induced by high energy radioactive beams. The midrapidity neutron/proton ratio and its transverse momentum dependence are found very sensitive to the high density behavior of nuclear symmetry energy. The nuclear radial flow, however, depends only weakly on the symmetry energy.Comment: 13 pages including 6 figures, submitted to Phys. Rev.

Double neutron-proton differential transverse flow as a probe for the high-density behavior of the nuclear symmetry energy

The double neutron-proton differential transverse flowtaken from two reaction systems using different isotopes of the same element is studied at incident beam energies of 400 and 800 MeV/nucleon within the framework of an isospin- and momentum-dependent hadronic transport model IBUU04. The double differential flow is found to retain about the same sensitivity to the density dependence of the nuclear symmetry energy as the single differential flow in the more neutron-rich reaction. Because the double differential flow reduces significantly both the systematic errors and the influence of the Coulomb force, it is thus more effective probe for the high-density behavior of the nuclear symmetry energy.Comment: 12 pages, 6 figures, version accepted for publication in Phys. Rev.

Single and double pi^{-}/pi^{+} ratios in heavy-ion reactions as probes of the high-density behavior of the nuclear symmetry energy

Based on an isospin- and momentum-dependent hadronic transport model IBUU04, effects of the nuclear symmetry energy on the single and double pi^{-}/pi^{+}ratios in central reactions of ^{132}Sn+^{124}Sn and ^{112}Sn+^{112}Sn at a beam energy of 400 MeV/nucleon are studied. It is found that around the Coulomb peak of the single pi^{-}/pi^{+} ratio the double pi^{-}/pi^{+} ratio taken from the two isotopic reactions retains about the same sensitivity to the density dependence of nuclear symmetry energy. Because the double pi^{-}/pi^{+}ratio can reduce significantly the systematic errors, it is thus a more effective probe for the high-density behavior of the nuclear symmetry energy.Comment: 11 pages, 3 figures, to appear in Physics Review

Progress Towards Determining the Density Dependence of the Nuclear Symmetry Energy Using Heavy-Ion Reactions

The latest development in determining the density dependence of the nuclear symmetry energy using heavy-ion collisions is reviewed. Within the IBUU04 version of an isospin- and momentum-dependent transport model using a modified Gogny effective interaction, recent experimental data from NSCL/MSU on isospin diffusion are found to be consistent with a nuclear symmetry energy of $E_{sym}(\rho)\approx 31.6(\rho /\rho_{0})^{1.05}$ 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.Comment: 10 pages. Talk given at the 21st Winter Workshop on Nuclear Dynamics, Breckenridge, Colorado, USA, Feb. 5-12, 2005. To appear in Heavy-Ion Physics (2005

1-[5-(Anthracen-9-yl)-3-(4-nitro­phen­yl)-4,5-dihydro-1H-pyrazol-1-yl]ethan-1-one

In the title compound, C25H19N3O3, steric repulsion between the methine H atom and one of the anthryl H atoms seems to be concomitant with the considerable distortion of the anthryl fragment from planarity. The side rings of the anthryl subtend an angle of 9.57 (8)°, which is an extreme value among the known reliably determined structures. This angle correlates with the length of the bond by which the anthryl is attached to the rest of the mol­ecule. In the anthryl fragment, the maximum deviation of one of the C atoms from the mean plane is 0.126 (3) Å and regards the carrier C atom involved in the repulsion between the anthryl and the methine H atoms. The inter­planar angle between the pyrazoline ring and the anthryl fragment is 88.36 (5)° and that between the pyrazoline and 4-nitro­phenyl rings is 8.80 (15)°. Weak inter­molecular C—H⋯N, C—H⋯π and π–π inter­actions [centroid–centroid distances of 3.7659 (17), 3.9477 (15) and 3.8972 (15) Å] are pesent in the structure