150,859 research outputs found

    String Representation for the 't Hooft Loop Average in the Abelian Higgs Model

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    Making use of the duality transformation, we derive in the Londons' limit of the Abelian Higgs Model string representation for the 't Hooft loop average defined on the string world-sheet, which yields the values of two coefficient functions parametrizing the bilocal correlator of the dual field strength tensors. The asymptotic behaviours of these functions agree with the ones obtained within the Method of Vacuum Correlators in QCD in the lowest order of perturbation theory. We demonstrate that the bilocal approximation to the Method of Vacuum Correlators is an exact result in the Londons' limit, i.e. all the higher cumulants in this limit vanish. We also show that at large distances, apart from the integration over metrics, the obtained string effective theory (which in this case reduces to the nonlinear massive axionic sigma model) coincides with the low-energy limit of the dual version of 4D compact QED, the so-called Universal Confining String Theory. We derive string tension of the Nambu-Goto term and the coupling constant of the rigidity term for the obtained string effective theory and demonstrate that the latter one is always negative, which means the stability of strings, while the positiveness of the former is confirmed by the present lattice data. These data enable us to find the Higgs boson charge and the vacuum expectation value of the Higgs field, which model QCD best of all. We also study dynamics of the weight factor of the obtained string representation for the 't Hooft average in the loop space. In conclusion, we obtain string representation for the partition function of the correlators of an arbitrary number of Higgs currents, by virtue of which we rederive the structure of the bilocal correlator of the dual field strength tensors, which yields the surface term in the string effective action.Comment: 11 pages, LaTeX, no figures, references are adde

    Gamma-ray bursts and the relevance of rotation-induced neutrino sterilization

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    A la Pontecorvo when one defines electroweak flavour states of neutrinos as a linear superposition of mass eigenstates one ignores the associated spin. If, however, there is a significant rotation between the neutrino source, and the detector, a negative helicity state emitted by the former acquires a non-zero probability amplitude to be perceived as a positive helicity state by the latter. Both of these states are still in the left-Weyl sector of the Lorentz group. The electroweak interaction cross sections for such helicity-flipped states are suppressed by a factor of (mν/Eν)2(m_\nu/E_\nu)^2, where mνm_\nu is the expectation value of the neutrino mass, and EνE_\nu is the associated energy. Thus, if the detecting process is based on electroweak interactions, and the neutrino source is a highly rotating object, the rotation-induced helicity flip becomes very significant in interpreting the data. The effect immediately generalizes to anti-neutrinos. Motivated by these observations we present a generalization of the Pontecorvo formalism and discuss its relevance in the context of recent data obtained by the IceCube neutrino telescope.Comment: 4 page

    Three-Species Diffusion-Limited Reaction with Continuous Density-Decay Exponents

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    We introduce a model of three-species two-particle diffusion-limited reactions A+B -> A or B, B+C -> B or C, and C+A -> C or A, with three persistence parameters (survival probabilities in reaction) of the hopping particle. We consider isotropic and anisotropic diffusion (hopping with a drift) in 1d. We find that the particle density decays as a power-law for certain choices of the persistence parameter values. In the anisotropic case, on one symmetric line in the parameter space, the decay exponent is monotonically varying between the values close to 1/3 and 1/2. On another, less symmetric line, the exponent is constant. For most parameter values, the density does not follow a power-law. We also calculated various characteristic exponents for the distance of nearest particles and domain structure. Our results support the recently proposed possibility that 1d diffusion-limited reactions with a drift do not fall within a limited number of distinct universality classes.Comment: 12 pages in plain LaTeX and four Postscript files with figure

    Double charmonium production at B-factories within light cone formalism

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    This paper is devoted to the study of the processes e^+e^- \to J/\Psi \eta_c, J/\Psi \eta_c', \psi' \eta_c, \psi' \eta_c' within light cone formalism. It is shown that if one disregards the contribution of higher fock states, the twist-3 distribution amplitudes needed in the calculation can be unambiguously determined from the twist-2 distribution amplitudes and equations of motion. Using models of the twist-2 distribution amplitudes the cross sections of the processes under study have been calculated. The results of the calculation are in agreement with Belle and BaBar experiments. It is also shown that relativistic and radiative corrections to the cross sections play crucial role in the achievement of the agreement between the theory and experiments. The comparison of the results of this paper with the results obtained in other papers has been carried out. In particular, it is shown that the results of papers where relativistic and radiative corrections were calculated within NRQCD are overestimated by a factor of ~1.5.Comment: 14 pages, 1 figur

    Dark matter and dark gauge fields

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    Following the unexpected theoretical discovery of a mass dimension one fermionic quantum field of spin one half, we now present first results on two _local_ versions. The Dirac and Majorana fields of the standard model of particle physics are supplemented by their natural counterparts in the dark matter sector. The possibility that a mass dimension transmuting symmetry may underlie a new standard model of particle physics is briefly suggested.Comment: This manuscript combines a plenary talk (by DVA) and an invited talk (by DS) at "Dark 2007 - Sixth International Heidelberg Conference on Dark Matter in Astro and Particle Physics (Sydney, Australia, 24th-28th September 2007)." 11 pages. v2: minor typos correcte

    Light Gravitinos at Colliders and Implications for Cosmology

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    Light gravitinos, with mass in the eV to MeV range, are well-motivated in particle physics, but their status as dark-matter candidates is muddled by early-Universe uncertainties. We investigate how upcoming data from colliders may clarify this picture. Light gravitinos are produced primarily in the decays of the next-to-lightest supersymmetric particle, resulting in spectacular signals, including di-photons, delayed and non-pointing photons, kinked charged tracks, and heavy metastable charged particles. We find that the Tevatron with 20/fb and the 7 TeV LHC with 1/fb may both see evidence for hundreds of light-gravitino events. Remarkably, this collider data is also well suited to distinguish between currently viable light-gravitino scenarios, with striking implications for structure formation, inflation, and other early-Universe cosmology.Comment: 12 pages, 6 figures. To be submitted to Phys. Rev. D

    Chiral symmetry breaking in a uniform external magnetic field II. Symmetry restoration at high temperatures and chemical potentials

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    Chiral symmetry is dynamically broken in quenched, ladder QED at weak gauge couplings when an external magnetic field is present. In this paper, we show that chiral symmetry is restored above a critical chemical potential and the corresponding phase transition is of first order. In contrast, the chiral symmetry restoration at high temperatures (and at zero chemical potential) is a second order phase transition.Comment: Latex; 12 pages; 8 postscript figures include

    Search for Free Fractional Electric Charge Elementary Particles

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    We have carried out a direct search in bulk matter for free fractional electric charge elementary particles using the largest mass single sample ever studied - about 17.4 mg of silicone oil. The search used an improved and highly automated Millikan oil drop technique. No evidence for fractional charge particles was found. The concentration of particles with fractional charge more than 0.16e (e being the magnitude of the electron charge) from the nearest integer charge is less than 4.71×10−224.71\times10^{-22} particles per nucleon with 95% confidence.Comment: 10 pages,LaTeX, 4 PS figures, submitted to PR
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