1,614 research outputs found
Gravitational radiation from elastic particle scattering in models with extra dimensions
In this paper we derive a formula for the energy loss due to elastic N to N
particle scattering in models with extra dimensions that are compactified on a
radius R. In contrast to a previous derivation we also calculate additional
terms that are suppressed by factors of frequency over compactification radius.
In the limit of a large compactification radius R those terms vanish and the
standard result for the non compactified case is recovered.Comment: 17 page
Event-by-event fluctuations of the charged particle ratio from non-equilibrium transport theory
The event by event fluctuations of the ratio of positively to negatively
charged hadrons are predicted within the UrQMD model. Corrections for finite
acceptance and finite net charge are derived. These corrections are relevant to
compare experimental data and transport model results to previous predictions.
The calculated fluctuations at RHIC and SPS energies are shown to be compatible
with a hadron gas. Thus, deviating by a factor of 3 from the predictions for a
thermalized quark-gluon plasma.Comment: This paper clarifies the previous predictions of Jeon and Koch
(hep-ph/0003168) and addresses issues raised in hep-ph/0006023. 2 Figures,
10pp, uses RevTe
Core-corona separation in the UrQMD hybrid model
We employ the UrQMD transport + hydrodynamics hybrid model to estimate the
effects of a separation of the hot equilibrated core and the dilute corona
created in high energy heavy ion collisions. It is shown that the fraction of
the system which can be regarded as an equilibrated fireball changes over a
wide range of energies. This has an impact especially on strange particle
abundancies. We show that such a core corona separation allows to improve the
description of strange particle ratios and flow as a function of beam energy as
well as strange particle yields as a function of centrality.Comment: 10 pages, 11 figures, version accepted by PR
Determination of the structure of the in collisions
Currently, the structure of the meson is unknown. Different
competing models of the exotic state exist, including the
possibilities that this state is either a mesonic molecule with dominating composition, a tetraquark, or a -gluon hybrid state. It is expected that the state is rather
strongly coupled to the channel and, therefore, can be produced in
and collisions at PANDA. We propose to test the
hypothetical molecular structure of by studying the or stripping reactions on a nuclear residue.Comment: 19 pages, 8 figures; version accepted in PL
Event-by-event fluctuations and the QGP
We discuss the physics underlying event-by-event fluctuations in relativistic
heavy ion collisions. We will emphasize how the fluctuations of particle ratios
can be utilized to explore the properties of the matter created in these
collisions. In particular, we will argue that the fluctutions of the ratio of
positively over negatively charged particles may serve as a unique signature
for the Quark Gluon Plasma.Comment: Proceedings Quark Matter 2001, Stony Brook, NY January 200
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