935 research outputs found

    Active Galactic Nuclei with Starbursts: Sources for Ultra High Energy Cosmic Rays

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    Ultra high energy cosmic ray events presently show a spectrum, which we interpret here as galactic cosmic rays due to a starburst in the radio galaxy Cen A pushed up in energy by the shock of a relativistic jet. The knee feature and the particles with energy immediately higher in galactic cosmic rays then turn into the bulk of ultra high energy cosmic rays. This entails that all ultra high energy cosmic rays are heavy nuclei. This picture is viable if the majority of the observed ultra high energy events come from the radio galaxy Cen A, and are scattered by intergalactic magnetic fields across most of the sky.Comment: 4 pages, 1 figure, proceedings of "High-Energy Gamma-rays and Neutrinos from Extra-Galactic Sources", Heidelber

    DEVELOPMENT AND RESULTS OF MEDICATIONS OF THE BURNS

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    No abstrac

    Conformal field theories with infinitely many conservation laws

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    Globally conformal invariant quantum field theories in a D-dimensional space-time (D even) have rational correlation functions and admit an infinite number of conserved (symmetric traceless) tensor currents. In a theory of a scalar field of dimension D-2 they were demonstrated to be generated by bilocal normal products of free massless scalar fields with an O(N), U(N), or Sp(2N) (global) gauge symmetry [BNRT]. Recently, conformal field theories "with higher spin symmetry" were considered for D=3 in [MZ] where a similar result was obtained (exploiting earlier study of CFT correlators). We suggest that the proper generalization of the notion of a 2D chiral algebra to arbitrary (even or odd) dimension is precisely a CFT with an infinite series of conserved currents. We shall recast and complement (part of) the argument of Maldacena and Zhiboedov into the framework of our earlier work. We extend to D=4 the auxiliary Weyl-spinor formalism developed in [GPY] for D=3. The free field construction only follows for D>3 under additional assumptions about the operator product algebra. In particular, the problem of whether a rational CFT in 4D Minkowski space is necessarily trivial remains open.Comment: 24 pages, Lecture at the TH Journal Club (CERN, February 2012

    Solar panels as air Cherenkov detectors for extremely high energy cosmic rays

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    Increasing interest towards the observation of the highest energy cosmic rays has motivated the development of new detection techniques. The properties of the Cherenkov photon pulse emitted in the atmosphere by these very rare particles indicate low-cost semiconductor detectors as good candidates for their optical read-out. The aim of this paper is to evaluate the viability of solar panels for this purpose. The experimental framework resulting from measurements performed with suitably-designed solar cells and large conventional photovoltaic areas is presented. A discussion on the obtained and achievable sensitivities follows.Comment: 6 pages, 8 eps figures included with epsfig, uses espcrc2.sty. Talk given at the Sixth Topical Seminar on Neutrino and Astroparticle Physics, San Miniato, Italy, 17-21 May 199

    Chiral Supersymmetric Gepner Model Orientifolds

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    We explicitly construct A-type orientifolds of supersymmetric Gepner models. In order to reduce the tadpole cancellation conditions to a treatable number we explicitly work out the generic form of the one-loop Klein bottle, annulus and Moebius strip amplitudes for simple current extensions of Gepner models. Equipped with these formulas, we discuss two examples in detail to provide evidence that in this setting certain features of the MSSM like unitary gauge groups with large enough rank, chirality and family replication can be achieved.Comment: 37 pages, TeX (harvmac), minor changes, typos corrected, to appear in JHE

    Four Dimensional CFT Models with Rational Correlation Functions

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    Recently established rationality of correlation functions in a globally conformal invariant quantum field theory satisfying Wightman axioms is used to construct a family of soluble models in 4-dimensional Minkowski space-time. We consider in detail a model of a neutral scalar field ϕ\phi of dimension 2. It depends on a positive real parameter c, an analogue of the Virasoro central charge, and admits for all (finite) c an infinite number of conserved symmetric tensor currents. The operator product algebra of ϕ\phi is shown to coincide with a simpler one, generated by a bilocal scalar field V(x1,x2)V(x_1,x_2) of dimension (1,1). The modes of V together with the unit operator span an infinite dimensional Lie algebra LVL_V whose vacuum (i.e. zero energy lowest weight) representations only depend on the central charge c. Wightman positivity (i.e. unitarity of the representations of LVL_V) is proven to be equivalent to c∈Nc \in N.Comment: 28 pages, LATEX, amsfonts, latexsym. Proposition 2.3, and Conjecture in Sec. 6 are revised. Minor errors are correcte

    Ultra-High Energy Cosmic Rays from Young Neutron Star Winds

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    The long-held notion that the highest-energy cosmic rays are of distant extragalactic origin is challenged by observations that events above ∼1020\sim 10^{20} eV do not exhibit the expected high-energy cutoff from photopion production off the cosmic microwave background. We suggest that these unexpected ultra-high-energy events are due to iron nuclei accelerated from young strongly magnetized neutron stars through relativistic MHD winds. We find that neutron stars whose initial spin periods are shorter than ∼4(BS/1013G)1/2\sim 4 (B_S/10^{13}{\rm G})^{1/2} ms, where BSB_S is the surface magnetic field, can accelerate iron cosmic rays to greater than ∼1020\sim 10^{20} eV. These ions can pass through the remnant of the supernova explosion that produced the neutron star without suffering significant spallation reactions. For plausible models of the Galactic magnetic field, the trajectories of the iron ions curve sufficiently to be consistent with the observed arrival directions of the highest energy events.Comment: 11 pages, 1 figure, replaced with revised version, some references adde
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