1,814 research outputs found
Production of antimatter Li nuclei in central Au+Au collisions at GeV
Combining the covariant coalescence model and a blast-wave-like analytical
parametrization for (anti-)nucleon phase-space freezeout configuration, we
explore light (anti-)nucleus production in central Au+Au collisions at
GeV. Using the nucleon freezeout configuration (denoted
by FO1) determined from the measured spectra of protons (p), deutrons (d) and
He, we find the predicted yield of He is significantly smaller than
the experimental data. We show this disagreement can be removed by using a
nucleon freezeout configuration (denoted by FO2) in which the nucleons are
assumed to freeze out earlier than those in FO1 to effectively consider the
effect of large binding energy value of He. Assuming the binding energy
effect also exists for the production of ,
, and due to
their similar binding energy values as He, we find the yields of these
heavier (anti-)nuclei can be enhanced by a factor of about one order, implying
that although the stable (anti-)Li nucleus is unlikely to be observed, the
unstable (anti-)Li nucleus could be produced in observable abundance in
Au+Au collisions at GeV where it may be identified
through the p- (-)
invariant mass spectrum. The future experimental measurement on
(anti-) would be very useful to understand the production
mechanism of heavier antimatter.Comment: 8 pages, 2 figures, 3 tables. Typos fixed and one ref added. Accepted
version to appear in PL
Probing QCD critical fluctuations from light nuclei production in relativistic heavy-ion collisions
Based on the coalescence model for light nuclei production, we show that the
yield ratio of
, d, and H in heavy-ion collisions is sensitive to the neutron relative
density fluctuation
at kinetic freeze-out. From recent experimental data in central Pb+Pb
collisions at ~GeV, ~GeV, ~GeV, ~GeV and
~GeV measured by the NA49 Collaboration at the CERN Super Proton
Synchrotron (SPS), we find a possible non-monotonic behavior of as a
function of the collision energy with a peak at ~GeV,
indicating that the density fluctuations become the largest in collisions at
this energy. With the known chemical freeze-out conditions determined from the
statistical model fit to experimental data, we obtain a chemical freeze-out
temperature of MeV and baryon chemical potential of MeV
at this collision energy, which are close to the critical endpoint in the QCD
phase diagram predicted by various theoretical studies. Our results thus
suggest the potential usefulness of the yield ratio of light nuclei in
relativistic heavy-ion collisions as a direct probe of the large density
fluctuations associated with the QCD critical phenomena.Comment: 6 pages, 1 figure, 2 tables. Correlations between neutron and proton
density fluctuations considered and presentation improved. Accepted version
to appear in PL
- …