15,442 research outputs found

    Anomalous Chiral Action from the Path-Integral

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    By generalizing the Fujikawa approach, we show in the path-integral formalism: (1) how the infinitesimal variation of the fermion measure can be integrated to obtain the full anomalous chiral action; (2) how the action derived in this way can be identified as the Chern-Simons term in five dimensions, if the anomaly is consistent; (3) how the regularization can be carried out, so as to lead to the consistent anomaly and not to the covariant anomaly. Our method uses Schwinger's ``proper-time'' representation of the Green's function and the gauge invariant point-splitting technique. We find that the consistency requirement and the point-splitting technique allow both an anomalous and a non-anomalous action. In the end, the nature of the vacuum determines whether we have an anomalous theory, or, a non-anomalous theoryComment: 28 page

    High Energy pp Elastic Scattering in Condensate Enclosed Chiral Bag Model and TOTEM Elastic Measurements at LHC at 7 TeV

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    We study high energy pp\small{\rm{pp}} and pˉp\small{\rm{\bar {p}p}} elastic scattering in the TeV region based on an effective field theory model of the proton. We phenomenologically investigate the main processes underlying elastic scattering and quantitatively describe the measured elastic dσ\small{\sigma}/dt at energies 7.0 TeV (LHC pp\small{\rm{pp}}), 1.96 TeV (Tevatron pˉp\small{\rm{\bar {p}p}}), and 0.630 TeV (SPS pˉp\small{\rm{\bar {p}p}}). Finally, we give our prediction for pp\small{\rm{pp}} elastic dσ\small{\sigma}/dt at 14 TeV that will be measured by the TOTEM Collaboration.Comment: Presented at EDS Blois 2013 (arXiv:1309.5705

    pp Elastic Scattering at LHC in a Nucleon-Structure Model

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    We predict pp elastic differential cross sections at LHC at c.m. energy 14 TeV and momentum transfer range |t| = 0 - 10 GeV*2 in a nucleon-structure model. In this model, the nucleon has an outer cloud of quark-antiquark condensed ground state, an inner shell of topological baryonic charge (r ~ 0.44F) probed by the vector meson omega, and a central quark-bag (r ~ 0.2F) containing valence quarks. We also predict elastic differential cross section in the Coulomb-hadronic interference region. Large |t| elastic scattering in this model arises from valence quark-quark scattering, which is taken to be due to the hard-pomeron (BFKL pomeron with next to leading order corrections). We present results of taking into account multiple hard-pomeron exchanges, i.e. unitarity corrections. Finally, we compare our prediction of pp elastic differential cross section at LHC with the predictions of various other models. Precise measurement of pp elastic differential cross section at LHC by the TOTEM group in the |t| region 0 - 5 GeV*2 will be able to distinguish between these models.Comment: To be published in the Proceedings of the 12th International Conference on Elastic and Diffractive Scattering, DESY, Hamburg. Presented by M. M. Islam, May 200

    An overview on the application of FRP composites in piling system

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    Traditional pile materials such as steel, concrete and timber have limited service life when used in harsh marine environment. Problems coupled with these piles include deterioration of wood, corrosion of steel and degradation of reinforced concrete. To offset this problem, a relatively new trend in deep foundation industry is to use a fibre reinforced polymer (FRP) composite materials as a substitute in piling system. The fundamental advantages of FRP composites compared to other pile materials include lightweight, high strength and possess resistance against corrosion. However, composite materials face hurdle because they do not have a long track record of use in civil engineering application particularly in piling system. To partly address this obstacle, this paper presents an overview in testing, design, and practice of composite piles. Importance is given to history, material types and properties, structural behaviour, geotechnical performance, and durability of composite piles

    Deep-Elastic pp Scattering at LHC from Low-x Gluons

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    Deep-elastic pp scattering at c.m. energy 14 TeV at LHC in the momentum transfer range 4 GeV*2 < |t| < 10 GeV*2 is planned to be measured by the TOTEM group. We study this process in a model where the deep-elastic scattering is due to a single hard collision of a valence quark from one proton with a valence quark from the other proton. The hard collision originates from the low-x gluon cloud around one valence quark interacting with that of the other. The low-x gluon cloud can be identified as color glass condensate and has size ~0.3 F. Our prediction is that pp differential cross section in the large |t| region decreases smoothly as momentum transfer increases. This is in contrast to the prediction of pp differential cross section with visible oscillations and smaller cross sections by a large number of other models.Comment: 10 pages, including 4 figure

    p p Elastic Scattering at LHC and Nucleon Structure

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    High energy elastic ppp p scattering at the Large Hadron Collider (LHC) at c.m. energy 14 TeV is predicted using the asymptotic behavior of σtot(s)\sigma_{tot}(s) and ρ(s)\rho(s) known from dispersion relation calculations and the measured elastic pˉp\bar p p differential cross section at s=546GeV\sqrt{s} = 546 {\rm GeV}. The effective field theory model underlying the phenomenological analysis describes the nucleon as having an outer cloud of quark-antiquark condensed ground state, an inner core of topological baryonic charge of radius 0.44F\simeq 0.44F and a still smaller valence quark-bag of radius 0.1F\lesssim 0.1 {\rm F}. The LHC experiment TOTEM (Total and Elastic Measurement), if carried out with sufficient precision from t=0|t| = 0 to t>10GeV2|t| > 10 {\rm GeV^2}, will be able to test this structure of the nucleon.Comment: 13 pages, 6 figures, to be published in the Modern Physics Letters

    Cylindrically symmetric wormholes

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    This paper discusses traversable wormholes that differ slightly but significantly from those of the Morris-Thorne type under the assumption of cylindrical symmetry. The throat is a piecewise smooth cylindrical surface resulting in a shape function that is not differentiable at some value. It is proposed that the regular derivative be replaced by a one-sided derivative at this value. The resulting wormhole geometry satisfies the weak energy condition.Comment: Supplied missing figures; 15 pages AMSTe
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