2,997 research outputs found
Parton recombination at all
Hadron production at all in heavy-ion collisions in the framework of
parton recombination is reviewed. It is shown that the recombination of thermal
and shower partons dominates the hadron spectra in the intermediate
region. In collisions, the physics of particle production at any
is basically the same as at . The Cronin effect is described as a
result of the final-state instead of the initial-state interaction. The
suppression of at high is due to the reduction of the soft
parton density on the deuteron side, thus resulting in less pions produced by
recombination, an explanation that requires no new physics. In
collisions large ratio is obtained because the thermal partons can
contribute to the formation of proton more than they do to the pion.Comment: 12 pages + 5 figures. Invited talk at Hard Probes 200
Correlations at intermediate
Correlations among hadrons in jets produced in heavy-ion collisions are
discussed in the framework of the recombination model. The basic correlation at
the parton level is among the shower partons arising from kinematical
constraint. The resultant correlation between hadrons at intermediate is
amazingly rich in characteristics.Comment: 10 pages including 12 figures. Talk presented at the MIT Workshop on
Correlations and Fluctuations in Relativistic Nuclear Collisions, April 200
Quark-hadron phase transition with surface fluctuation
The effect of surface fluctuation on the observables of quark-hadron phase
transition is studied. The Ginzburg-Landau formalism is extended by the
inclusion of an extra term in the free energy that depends on the vertical
displacements from a flat surface. The probability that a bin has a particular
net displacement is determined by lattice simulation, where the physics input
is color confinement. The surface fluctuation from bin to bin is related to
multiplicity fluctuation, which in turn is measured by the factorial moments.
It is found that both the F-scaling behavior and the scaling exponent are
essentially unaffected by the inclusion of surface fluctuation.Comment: 9 pages, LaTex, 7 figures in a single postscript file, submitted to
Phys. Rev.
Fragmentation or Recombination at High p_T?
All hadronization processes, including fragmentation, are shown to proceed
through recombination. The shower partons in a jet turn out to play an
important role in describing the p_T spectra of hadrons produced in heavy-ion
collisions. Due to the recombination of the shower partons with the soft
thermal partons, the structure of jets produced in AA collisions is not the
same as that of jets produced in pp collisions.Comment: Talk given at Quark Matter 200
Void Analysis of Hadronic Density Fluctuations at Phase Transition
The event-to-event fluctuations of hadron multiplicities are studied for a
quark system undergoing second-order phase transition to hadrons. Emphasis is
placed on the search for an observable signature that is realistic for
heavy-ion collisions. It is suggested that in the 2-dimensional y-phi space the
produced particles selected in a very narrow p_T window may exhibit clustering
patterns even when integrated over the entire emission time. Using the Ising
model to simulate the critical phenomenon and taking into account a p_T
distribution that depends on the emission time, we study in the framework of
the void analysis proposed earlier and find scaling behavior. The scaling
exponents turn out to be larger than the ones found before for pure
configurations without mixing. The signature is robust in that it is
insensitive to the precise scheme of simulating time evolution. Thus it should
reveal whether or not the dense matter created in heavy-ion collisions is a
quark-gluon plasma before hadronization.Comment: 11 pages in LaTeX + 6 figures in p
Evolution of shower parton distributions in a jet from quark recombination model
The evolution of shower parton distributions in a jet is investigated in the
framework of quark recombination model. The distributions are parameterized and
the dependence of the parameters is given by polynomials of for
a wide range of .Comment: 5 pages in RevTeX, 3 figures in ep
Comparison of Nuclear Suppression Effects on Meson Production at High p_T and p_L
The medium effect on the pion distribution at high in collisions
is compared to that of the pion distribution at high in collisions.
Both the suppression of the spectra and the energy losses of the measured pions
are studied. Although the medium effect on is larger than on , the
difference is found surprisingly to be not as big as one would naively expect.Comment: 8 RevTex pages with 5 figure
Ridge Formation Induced by Jets in Collisions at 7 TeV
An interpretation of the ridge phenomenon found in pp collisions at 7 TeV is
given in terms of enhancement of soft partons due to energy loss of semihard
jets. A description of ridge formation in nuclear collisions can directly be
extended to pp collisions, since hydrodynamics is not used, and azimuthal
anisotropy is generated by semihard scattering. Both the p_T and multiplicity
dependencies are well reproduced. Some suggestions are made about other
observables.Comment: Expanded version to be published in Phys. Rev.
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