13 research outputs found
Hydrodynamic Evolution of Spherical Fireball In Relativistic Heavy Ion Collisions
Evolution process could be calculated from the relativistic hydrodynamic
equation with certain estimated initial conditions about a single spherical
fireball here. So one could estimate a kind of initial condition qualitatively
with a possible energy density about , based
on this process to fit the experimental data at thermal freeze-out. The
evolution from a cylindrical fireball will be discussed simply in a later
chapter.Comment: 9 pages, 8 figure
Hawking radiation from spherically symmetrical gravitational collapse to an extremal R-N black hole for a charged scalar field
Sijie Gao has recently investigated Hawking radiation from spherically
symmetrical gravitational collapse to an extremal R-N black hole for a real
scalar field. Especially he estimated the upper bound for the expected number
of particles in any wave packet belonging to spontaneously
produced from the state , which confirms the traditional belief that
extremal black holes do not radiate particles. Making some modifications, we
demonstrate that the analysis can go through for a charged scalar field.Comment: 10 pages, 1 figur
Hadronization Approach for a Quark-Gluon Plasma Formed in Relativistic Heavy Ion Collisions
A transport model is developed to describe hadron emission from a strongly
coupled quark-gluon plasma formed in relativistic heavy ion collisions. The
quark-gluon plasma is controlled by ideal hydrodynamics, and the hadron motion
is characterized by a transport equation with loss and gain terms. The two sets
of equations are coupled to each other, and the hadronization hypersurface is
determined by both the hydrodynamic evolution and the hadron emission. The
model is applied to calculate the transverse momentum distributions of mesons
and baryons, and most of the results agree well with the experimental data at
RHIC.Comment: 16 pages, 24 figures. Version accepted by PR
Production Ratios of Strange Baryons from QGP with Diquarks
Assuming that vector and scalar diquarks exist in the Quark-Gluon Plasma near
the critical temporature , baryons can be produced through the processes
of quarks and diquarks forming baryon states. Ratios of different
baryons can be estimated through this method, if such kind of QGP with diquarks
can exists.Comment: Correct some expressions of equation
Estimations of at RHIC from a QGP Model with Diquarks
Assuming that axial-vector and scalar diquarks exist in the Quark-Gluon
Plasma near the critical temporature , baryons can be produced from
quark-diquark interactions. In RHIC conditions ( and
), the ratio may be larger than 1, based on
the concept that QGP with diquarks would exist. This unusual result might be a
helpful evidence for QGP existing in RHIC.Comment: 6 pages, 1 figure. accepted by J.Phys.
Decay and Right-handed Top-bottom Charged Current
We introduce an anomalous top quark coupling (right-handed current) into
Standard Model Lagrangian. Based on this, a more complete calculation of decay including leading log QCD corrections from to
in addition to corrections from to is given. The inclusive decay
rate is found to be suppressed comparing with the case without QCD running from
to except at the time of small values of . e.g. when
, it is only of the value given before. As
goes smaller, this contribution is an enhancement like standard model case.
From the newly experiment of CLEO Collaboration, strict restrictions to
parameters of this top-bottom quark coupling are found.Comment: 20 Pages, 2 figures( ps file uuencoded)
Volume Effect of Bound States in Quark Gluon Plasma
Bound states, such as qq and q¯q, may exist in the Quark Gluon Plasma. As the system is at high density, the volume of the bound states may evoke a reduction to the phase space. We introduce an extended bag model to investigate qualitatively the volume effect on the properties of the system. We find a limit temperature where the bound states start to be completely melted. PACS number(s): 12.38.Mh 25.75.-