6,245 research outputs found
The Transformation of Europe
Professor Weiler confronts the most complex and multi-faceted, and indeed the deepest change in contemporary Europe-the evolving relationship between the European Community and its Member States. Without denying the importance of 1992, he argues that it was preceded by two deeper mutations in the structure of the European Community, mutations we must understand if we are to grasp fully the significance of 1992. Tracing the evolution of the Community's political structure from 1958 to the present, the Article concentrates on constitutional aspects of the Community, specifically relationships between the Community and Member States along the axes of political power and legal norms. Professor Weiler then confronts the evolving question of the division of competences between Community and Member State. Analyzing law's role in the Community in its living political matrix rather than as abstract ideal, Weiler follows the evolution of these center-periphery tensions and concludes with some observations on ideology, ethos and political culture in post-1992 Europe
End of the cosmic neutrino energy spectrum
There may be a high-energy cutoff of neutrino events in IceCube data. In
particular, IceCube does not observe either continuum events above 2 PeV, or
the Standard Model Glashow-resonance events expected at 6.3 PeV. There are also
no higher energy neutrino signatures in the ANITA and Auger experiments. This
absence of high-energy neutrino events motivates a fundamental restriction on
neutrino energies above a few PeV. We postulate a simple scenario to terminate
the neutrino spectrum that is Lorentz-invariance violating, but with a limiting
neutrino velocity that is always smaller than the speed of light. If the
limiting velocity of the neutrino applies also to its associated charged
lepton, then a significant consequence is that the two-body decay modes of the
charged pion are forbidden above two times the maximum neutrino energy, while
the radiative decay modes are suppressed at higher energies. Such stabilized
pions may serve as cosmic ray primaries.Comment: 6 pages. Version to appear in PL
An Auger test of the Cen A model of highest energy cosmic rays
If, as recently proposed by Farrar and Piran, Cen A is the source of cosmic rays detected above the Greisen-Zatsepin-Kuz'min cutoff, neutrons are more probable than protons to be observed along its line of sight. This is because the proton flux is rendered nearly isotropic by G) intergalactic magnetic fields. With the anticipated aperture of the Southern Auger Observatory, one may expect on the order of 10 neutron events/year above eV in the line of sight of Cen A
G328.4+0.2 : A large and luminous Crab-like supernova remnant
We report on radio continuum and HI observations of the radio source
G328.4+0.2 using the Australia Telescope Compact Array. Our results confirm
G328.4+0.2 to be a filled-center nebula with no surrounding shell, showing
significant linear polarization and an almost flat spectral index. These
results lead us to conclude that G328.4+0.2 is a Crab-like, or ``plerionic'',
supernova remnant (SNR), presumably powered by an unseen central pulsar. HI
absorption towards G328.4+0.2 puts a lower limit on its distance of 17.4 +/-
0.9 kpc, making it the largest (D=25 pc) and most luminous (L_R = 3e35 erg/s)
Crab-like SNR in the Galaxy. We infer G328.4+0.2 to be significantly older than
the Crab Nebula, but powered by a pulsar which is fast spinning (P<20 ms) and
which has a comparatively low magnetic field (B<1e12 G). We propose G328.4+0.2,
G74.9+1.2 and N157B as a distinct group of large-diameter, high-luminosity
Crab-like SNRs, all powered by fast-spinning low-field pulsars.Comment: 7 pages, 3 embedded EPS figures, uses emulateapj.sty. Accepted to
ApJ. Abstract corrected so that distance is now in kpc, not pc
Clustering in Highest Energy Cosmic Rays: Physics or Statistics?
Directional clustering can be expected in cosmic ray observations due to
purely statistical fluctuations for sources distributed randomly in the sky. We
develop an analytic approach to estimate the probability of random cluster
configurations, and use these results to study the strong potential of the
HiRes, Auger, Telescope Array and EUSO/OWL/AirWatch facilities for deciding
whether any observed clustering is most likely due to non-random sources.Comment: 19 pages, LaTeX, 3 figure
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