Nonextensive hydrodynamics for relativistic heavy-ion collisions

The nonextensive one-dimensional version of a hydrodynamical model for multiparticle production processes is proposed and discussed. It is based on nonextensive statistics assumed in the form proposed by Tsallis and characterized by a nonextensivity parameter $q$. In this formulation the parameter $q$ characterizes some specific form of local equilibrium which is characteristic for the nonextensive thermodynamics and which replaces the usual local thermal equilibrium assumption of the usual hydrodynamical models. We argue that there is correspondence between the perfect nonextensive hydrodynamics and the usual dissipative hydrodynamics. It leads to simple expression for dissipative entropy current and allows for predictions for the ratio of bulk and shear viscosities to entropy density, $\zeta/s$ and $\eta/s$, to be made.Comment: Final version accepted for publication in Phys. Rev.

The angular resolution of air shower gamma ray telescopes

A crucial charactristic of air shower arrays in the field of high energy gamma-ray astronomy is their angular resolving power, the arrival directions being obtained by the time of flight measurements. A small air shower array-telescope is used to study the resolution in the definition of the shower front as a function of the shower size

Kadomtsev-Petviashvili equation in Relativistic Fluid Dynamics

The Kadomtsev-Petviashvili (KP) nonlinear wave equation is the three dimensional generalization of the Korteveg-de Vries (KdV) equation. We show how to obtain the cylindrical KP (cKP) and cartesian KP in relativistic fluid dynamics. The obtained KP equations describe the evolution of perturbations in the baryon density in a strongly interacting quark gluon plasma (sQGP) at zero temperature. We also show the analytical solitary wave solution of the KP equations in both cases

On the absorption and production cross sections of KK and K∗K^*

We have computed the isospin and spin averaged cross sections of the processes $\pi K^*\to \rho K$ and $\rho K^*\to \pi K$, which are crucial in the determination of the abundances of $K^*$ and $K$ in heavy ion collisions. Improving previous calculations, we have considered several mechanisms which were missing, such as the exchange of axial and vector resonances ($K_1(1270)$, $K^*_2(1430)$, $h_1(1170)$, etc...) and also other processes such as $\pi K^*\to \omega K, \phi K$ and $\omega K^*,\,\phi K^*\to \pi K$. We find that some of these mechanisms give important contributions to the cross section. Our results also suggest that, in a hadron gas, $K^*$ production might be more important than its absorption

Virtual Meson Cloud of the Nucleon and Intrinsic Strangeness and Charm

We have applied the Meson Cloud Model (MCM) to calculate the charm and strange antiquark distribution in the nucleon. The resulting distribution, in the case of charm, is very similar to the intrinsic charm momentum distribution in the nucleon. This seems to corroborate the hypothesis that the intrinsic charm is in the cloud and, at the same time, explains why other calculations with the MCM involving strange quark distributions fail in reproducing the low x region data. From the intrinsic strange distribution in the nucleon we have extracted the strangeness radius of the nucleon, which is in agreement with other meson cloud calculations.Comment: 9 pages RevTex, 4 figure

Experimental results on gamma-ray sources at E sub 0 = 10(13) - 10(14) eV

The detection of very high energy gamma ray sources has been reported in the last few years by means of extensive air shower observations. The Plateau Rosa array for the registration of the arrival directions of extensive air showers has been operating since 1980 and first results on Cygnus X-3 have been reported. Here, the status of observations of Cygnus X-3 and of the Crab Pulsar are reported

J/Psi Propagation in Hadronic Matter

We study J/$\psi$ propagation in hot hadronic matter using a four-flavor chiral Lagrangian to model the dynamics and using QCD sum rules to model the finite size effects manifested in vertex interactions through form factors. Charmonium breakup due to scattering with light mesons is the primary impediment to continued propagation. Breakup rates introduce nontrivial temperature and momentum dependence into the J/$\psi$ spectral function.Comment: 6 Pages LaTeX, 3 postscript figures. Proceedings for Strangeness in Quark Matter 2003, Atlantic Beach, NC, March 12-17, 2003; minor corrections in version 2, to appear in J. Phys.