103,140 research outputs found
ratios in relativistic heavy-ion collisions
We study ratios as a function of centrality (participant nucleon
number), transverse mass (), and rapidity, in heavy-ion collisions at beam
energies between 1A and 2A GeV. We use the relativistic transport model that
includes expicitly the strangeness degrees of freedom and consider two
scenarios for kaon properties in dense matter, one with and one without medium
modifications of their properties. In both scenarios, The ratio does
not change very much with the centrality, while the and
ratios increase with increasing centrality. Significant differences are
predicted, both in magnitudes and shapes, for the spectra and rapidity
distributions of ratio. Experimental measurement of these ratios,
currently under investigation by the FOPI, KaoS, E866, and E895 collaborations,
will be useful in revealing the kaon in-medium properties.Comment: RevTex, 10 pages, including 17 postscript figures, submitted to Phys.
Rev.
Difficulties in probing density dependent symmetry potential with the HBT interferometry
Based on the updated UrQMD transport model, the effect of the symmetry
potential energy on the two-nucleon HBT correlation is investigated with the
help of the coalescence program for constructing clusters, and the CRAB
analyzing program of the two-particle HBT correlation. An obvious non-linear
dependence of the neutron-proton (or neutron-neutron) HBT correlation function
() at small relative momenta on the stiffness factor of the
symmetry potential energy is found: when , the
increases rapidly with increasing , while it starts to saturate if
. It is also found that both the symmetry potential energy
at low densities and the conditions of constructing clusters at the late stage
of the whole process influence the two-nucleon HBT correlation with the same
power.Comment: 11 pages, 4 figure
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
- …