12,651 research outputs found
Crystal Barrel Results on Two-Body Decays of the Scalar Glueball
The Crystal Barrel Collaboration observes scalar meson resonances in annihilation. Based on the measurements and partial wave analyses these are
candidates for the P groundstate nonet. The supernummerary
resonance is identified as a scalar groundstate glueball. Important information
for its characterization comes from the decay pattern into pseudoscalar and
scalar mesons. Data on kaonic decays in the mass region up to 1700 MeV are now
avaible at Crystal Barrel. New analysis results are presented.Comment: 5 pages, Latex, 3 eps figures, talk presented at EPS-HEP'97
conference in Jerusalem, Israel, 19-26 Aug. 199
A spatially resolved SSC Shock-in-Jet model
In this paper a spatially resolved, fully self-consistent SSC model is
presented. The observable spectral energy distribution (SED) evolves entirely
from a low energetic delta distribution of injected electrons by means of the
implemented microphysics of the jet. These are in particular the properties of
the shock and the ambient plasma, which can be varied along the jet axis. Hence
a large variety of scenarios can be computed, e.g. the acceleration of
particles via multiple shocks. Two acceleration processes, shock acceleration
and stochastic acceleration, are taken into account. From the resulting
electron distribution the SED is calculated taking into account synchrotron
radiation, inverse Compton scattering (full cross section) and synchrotron self
absorption. The model can explain SEDs where cooling processes are crucial. It
can verify high variability results from acausal simulations and produce
variability not only via injection of particles, but due to the presence of
multiple shocks. Furthermore a fit of the data, obtained in the 2010
multi-frequency campaign of Mrk501, is presented.Comment: 4 pages, 2 figures; appeared in the proceedings of the conference:
"High Energy Phenomena in Relativistic Outflows (HEPRO) III", held in
Barcelona, Spain, June 27th-July 1st 2011 (IJMPCS
Three-wave interactions of dispersive plasma waves propagating parallel to the magnetic field
Three-wave interactions of plasma waves propagating parallel to the mean
magnetic field at frequencies below the electron cyclotron frequency are
considered. We consider Alfv\'en--ion-cyclotron waves,
fast-magnetosonic--whistler waves, and ion-sound waves. Especially the weakly
turbulent low-beta plasmas like the solar corona are studied, using the
cold-plasma dispersion relation for the transverse waves and the
fluid-description of the warm plasma for the longitudinal waves. We analyse the
resonance conditions for the wave frequencies and wavenumbers , and
the interaction rates of the waves for all possible combinations of the three
wave modes, and list those reactions that are not forbidden.Comment: accepted for publication in Advanced Science Letter
Multi-band implications of external-IC flares
Very fast variability on scales of minutes is regularly observed in Blazars.
The assumption that these flares are emerging from the dominant emission zone
of the very high energy (VHE) radiation within the jet challenges current
acceleration and radiation models. In this work we use a spatially resolved and
time dependent synchrotron-self-Compton (SSC) model that includes the full time
dependence of Fermi-I acceleration. We use the (apparent) orphan -ray
flare of \textit{Mrk501} during MJD 54952 and test various flare scenarios
against the observed data. We find that a rapidly variable external radiation
field can reproduce the high energy lightcurve best. However, the effect of the
strong inverse Compton (IC) cooling on other bands and the X-ray observations
are constraining the parameters to rather extreme ranges. Then again other
scenarios would require parameters even more extreme or stronger physical
constraints on the rise and decay of the source of the variability which might
be in contradiction with constraints derived from the size of the black hole's
ergosphere.Comment: accepted for publication in Astroparticle Physic
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