285,742 research outputs found
Antikaon flow in heavy-ion collisions: the effects of absorption and mean fields
We study antikaon flow in heavy-ion collisions at SIS energies based on the
relativistic transport model (RVUU 1.0). The production of antikaons from both
baryon-baryon and pion-baryon collisions are included. Taking into account only
elastic and inelastic collisions of the antikaon with nucleons and neglecting
its mean-field potential as in the cascade model, a strong antiflow or
anti-correlation of antikaons with respect to nucleons is seen as a result of
the strong absorption of antikaons by nucleons. However, the antiflow of
antikaons disappears after including also their propagation in the attractive
mean-field potential. The experimental measurement of antikaon flow in
heavy-ion collision will be very useful in shedding lights on the relative
importance of antikaon absorption versus its mean-field potential.Comment: 12 pages, 2 postscript figures omitted in the original submission are
included, to appear in Phys. Rev.
Antiproton production in Ni+Ni collisions at 1.85 GeV/nucleon
Antiproton production in Ni+Ni collisions at 1.85 GeV/nucleon is studied in
the relativistic Vlasov-Uehling-Uhlenbeck model. The self-energies of the
antiproton are determined from the nucleon self-energies by the G-parity
transformation. Also, the final-state interactions of the antiproton including
both rescattering and annihilation are explicitly treated. With a soft nuclear
equation of state, the calculated antiproton momentum spectrum is in good
agreement with recent experimental data from the heavy-ion synchrotron at GSI.
The effect due to the reduced nucleon and antinucleon masses in a medium is
found to be more appreciable than in earlier Bevalac experiments with lighter
systems and at higher energies.Comment: 10 pages, 4 figures available upon request to [email protected].
TAMUNT-940
Sensitivity of neutron radii in the sigma_-$ rho_ coupling corrections in relativistic mean field theory
We study the sensitivity of the neutron skin thickness, , in a Pb
nucleus to the addition of nucleon-sigma-rho coupling corrections to a
selection (PK1, NL3, S271, Z271) of interactions in relativistic mean field
model. The PK1 and NL3 effective interactions lead to a minimum value of =
0.16 fm in comparison with the original value of = 0.28 fm. The S271 and
Z271 effective interactions yield even smaller values of = 0.11 fm, which
are similar to those for nonrelativistic mean field models. A precise
measurement of the neutron radius, and therefore , in Pb will place
an important constraint on both relativistic and nonrelativistic mean field
models. We also study the correlation between the radius of a 1.4 solar-mass
neutron star and .Comment: 40 pages 13 figures. to be published in Physical Review
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