51 research outputs found
Momentum anisotropies in the quark coalescence model
Based on the quark coalescence model, we derive relations among the momentum
anisotropies of mesons and baryons in relativistic heavy ion collisions from a
given, but arbitrary azimuthal distribution for the partons. Besides the
familiar even Fourier coefficients such as the elliptic flow, we also pay
attention to odd Fourier coefficients such as the directed flow, which has been
observed at finite rapidity even at RHIC energies.Comment: 5 page
Thermal Charm Production in Quark-Gluon Plasma at LHC
Charm production from the quark-gluon plasma created in the midrapidity of
central heavy ion collisions at the Large Hadron Collider (LHC) is studied in
the next-to-leading order in QCD. Using a schematic longitudinally
boost-invariant and transversally expanding fire-cylinder model, we find that
charm production could be appreciably enhanced at LHC as a result of the high
temperature that is expected to be reached in the produced quark-gluon plasma.
Sensitivities of our results to the number of charm quark pairs produced from
initial hard scattering, the initial thermalization time and temperature of the
quark-gluon plasma, and the charm quark mass are also studied.Comment: 8 pages, 9 figures; adding a figure and relevant discussion on the
sensitivity of our results to the number of charm quark pairs produced from
initial hard scattering. Version accepted for publication in PR
Properties of Hadrons in the Nuclear Medium
This review is devoted to the discussion of hadron properties in the nuclear
medium and its relation to the partial restoration of chiral symmetry. Special
attention is given to disentangle in-medium effects due to conventional
many-body interactions from those due to the change of the chiral condensate.
In particular, we shall discuss medium effects on the Goldstone bosons (pion,
kaon and eta), the vector mesons (rho, omega, phi), and the nucleon. Also, for
each proposed in-medium effect the experimental consequence and results will be
reviewed.Comment: 43 pages, 8 figures, uses epsf-style file. To appear in Ann. Rev.
Nucl. Part. Sci. Vol 4
Charmed hadron chemistry in relativistic heavy-ion collisions
We develop for charmed hadron production in relativistic heavy-ion collisions
a comprehensive coalescence model that includes an extensive set of and
-wave hadronic states as well as the strict energy-momentum conservation,
which ensures the boost invariance of the coalescence probability and the
thermal limit of the produced hadron spectrum. By combining our hadronization
scheme with an advanced Langevin-hydrodynamics model that incorporates both
elastic and inelastic energy loss of heavy quarks inside the dynamical
quark-gluon plasma, we obtain a successful description of the
-integrated and differential and ratios
measured at RHIC and the LHC. We find that including the effect of radial flow
of the medium is essential for describing the enhanced ratio
observed in relativistic heavy-ion collisions. We also find that the puzzling
larger ratio observed in Au+Au collisions at RHIC than in Pb+Pb
collisions at the LHC is due to the interplay between the effects of the QGP
radial flow and the charm quark transverse momentum spectrum at hadronization.
Our study further suggests that charmed hadrons have larger sizes in medium
than in vacuum.Comment: 6 pages, 5 figure
Determining the density dependence of the nuclear symmetry energy using heavy-ion reactions
We review recent progress in the determination of the subsaturation density
behavior of the nuclear symmetry energy from heavy-ion collisions as well as
the theoretical progress in probing the high density behavior of the symmetry
energy in heavy-ion reactions induced by high energy radioactive beams. We
further discuss the implications of these results for the nuclear effective
interactions and the neutron skin thickness of heavy nuclei.Comment: 12 pages, 5 figures. Talk given at the International workshop on
nuclear dynamics in heavy-ion reactions and neutron stars, July, 10-14,
Beijing, Chin
Hadron widths in mixed-phase matter
We derive classically an expression for a hadron width in a two-phase region
of hadron gas and quark-gluon plasma (QGP). The presence of QGP gives hadrons
larger widths than they would have in a pure hadron gas. We find that the
width observed in a central Au+Au collision at
GeV/nucleon is a few MeV greater than the width in a pure hadron gas. The part
of observed hadron widths due to QGP is approximately proportional to
.Comment: 8 pages, latex, no figures, KSUCNR-002-9
Partonic effects on anisotropic flows at RHIC
We report recent results from a multiphase transport (AMPT) model on the
azimuthal anisotropies of particle momentum distributions in heavy ion
collisions at the Relativistic Heavy Ion Collider. These include higher-order
anisotropic flows and their scaling, the rapidity dependence of anisotropic
flows, and the elliptic flow of charm quarks.Comment: 7 pages, 5 figures, talk given at "Hot Quarks 2004", July 18-24,
2004, Taos Valley, NM, US
Pseudorapidity dependence of anisotropic flows in relativistic heavy-ion collisions
The pseudorapidity dependence of anisotropic flows , ,
, and of charged hadrons in heavy-ion collisions at the Relativistic
Heavy Ion Collider is studied in a multi-phase transport model. We find that
while the string melting scenario, in which hadrons that are expected to be
formed from initial strings are converted to their valence quarks and
antiquarks, can explain the measured -dependence of and of charged hadrons at midrapidity with a parton scattering cross section of
about 10 \textrm{mb}, the scenario without string melting reproduces better the
recent data on and of charged hadrons at large pseudorapidity
in Au + Au collisions at AGeV . Our results thus suggest that a
partonic matter is formed during early stage of relativistic heavy ion
collisions only around midrapidity and that strings remain dominant at large
rapidities. The -dependence of , , and
for charged hadrons at forward pseudorapidity is also predicted, and we find
that while and are appreciable at large pseudorapidity the
higher-order anisotropic flows and are essentially zero.Comment: 5 pages, 4 figures, revised version, to appear in PL
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