261 research outputs found
Increase of Effective String Tension and Production of Strange Particles
The increase of effective string tension as a result of the hard gluon kinks
on a string is investigated using a parametrization form. In this form the
effective string tension increasing with energies in hadron-hadron collisions
is due to the mini-jet (gluon) production in the collisions. The data of the
energy dependence of the strange quark suppression factor in hh collisions are
very well reproduced with this mechanism. Meanwhile, the experimental phenomena
of approximate energy independence of the strange quark suppression factor in
ee-annihilations are discussed.Comment: LaTeX, 2 figure
Enhancement of singly and multiply strangeness in p-Pb and Pb-Pb collisions at 158A GeV/c
The idea that the reduction of the strange quark suppression in string
fragmentation leads to the enhancement of strange particle yield in
nucleus-nucleus collisions is applied to study the singly and multiply strange
particle production in p-Pb and Pb-Pb collisions at 158A GeV/c. In this
mechanism the strange quark suppression factor is related to the effective
string tension, which increases in turn with the increase of the energy, of the
centrality and of the mass of colliding system. The WA97 observation that the
strange particle enhancement increases with the increasing of centrality and of
strange quark content in multiply strange particles in Pb-Pb collisions with
respect to p-Pb collisions was accounted reasonably.Comment: 8 pages, 3 PostScript figures, in Latex form. submitted to PR
LUCIAE 3.0: A new version of a computer program for Firecracker Model and rescattering in relativistic heavy-ion collisions
LUCIAE is a Monte Carlo program that, connected to FRITIOF, implements both
the Firecracker Model (FCM), a possible mechanism for collective multi-gluon
emission from the colour fields of interacting strings, and the reinteraction
of the final state hadrons in relativistic heavy ion collisions. This paper
includes a brief presentation of the dynamics of LUCIAE with an emphasis on the
new features in this version, as well as a description of the program.Comment: LaTeX, no figur
Energy and centrality dependences of charged multiplicity density in relativistic nuclear collisions
Charged multiplicity density and number of participant nucleons in relativistic nuclear collisions
The energy and centrality dependences of charged particle pseudorapidity
density in relativistic nuclear collisions were studied using a hadron and
string cascade model, JPCIAE. Both the relativistic experimental
data and the PHOBOS and PHENIX data at RHIC energy could be fairly
reproduced within the framework of JPCIAE model and without retuning the model
parameters. The predictions for collisions at the LHC energy were also
given. We computed the participant nucleon distributions using different
methods. It was found that the number of participant nucleons is not a well
defined variable both experimentally and theoretically. Thus it may be
inappropriate to use the charged particle pseudorapidity density per
participant pair as a function of the number of participant nucleons for
distinguishing various theoretical models. A discussion for the effect of
different definitions in nuclear radius (diffused or sharp) was given.Comment: 15 pages, 7 figure
Net charge fluctuation and string fragmentation
We present simulation results of net charge fluctuation in collisions
at =130 GeV from a dynamic model, JPCIAE. The calculations are
done for the quark-gluon phase before hadronization, the pion gas, the
resonance pion gas from and decays and so on. The simulations
of the charge fluctuation show that the discrepancy exists between the dynamic
model and the thermal model for a pion gas and a resonance pion gas from
and decays while the simulated charge fluctuation of the quark-gluon
phase is close to the thermal model prediction. JPCIAE results of net charge
fluctuation in the hardonic phase are nearly 4-5 times larger than one for the
quark-gluon phase, which implies that the charge fluctuation in the quark-gluon
phase may not survive the hadronization (string fragmentation) as implemented
in JPCIAE.Comment: 9 pages, 3 figure
Systematic study of elliptic flow parameter in the relativistic nuclear collisions at RHIC and LHC energies
We employed the new issue of a parton and hadron cascade model PACIAE 2.1 to
systematically investigate the charged particle elliptic flow parameter
in the relativistic nuclear collisions at RHIC and LHC energies. With randomly
sampling the transverse momentum and components of the particles
generated in string fragmentation on the circumference of an ellipse instead of
circle originally, the calculated charged particle and
fairly reproduce the corresponding experimental data in the Au+Au/Pb+Pb
collisions at =0.2/2.76 TeV. In addition, the charged particle
and in the p+p collisions at =7 TeV as well as
in the p+Au/p+Pb collisions at =0.2/5.02 TeV are predicted.Comment: 7 pages, 5 figure
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