39,710 research outputs found

    Application of Finite Elastic Theory to the Deformation of Rubbery Materials

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    The purpose of this discussion, then, is to show how the nature of the strain energy function can be deduced from experiments on rubbery materials

    Gamma-ray Luminosity and Photon Index Evolution of FSRQ Blazars and Contribution to the Gamma-ray Background

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    We present the redshift evolutions and distributions of the gamma-ray luminosity and photon spectral index of flat spectrum radio quasar (FSRQ) type blazars, using non-parametric methods to obtain the evolutions and distributions directly from the data. The sample we use for analysis consists of almost all FSRQs observed with a greater than approximately 7 sigma detection threshold in the first year catalog of the Fermi Gamma-ray Space Telescope's Large Area Telescope, with redshfits as determined from optical spectroscopy by Shaw et al. We find that FSQRs undergo rapid gamma-ray luminosity evolution, but negligible photon index evolution, with redshift. With these evolutions accounted for we determine the density evolution and luminosity function of FSRQs, and calculate their total contribution to the extragalactic gamma-ray background radiation, resolved and unresolved, which is found to be 16(+10/-4)%, in agreement with previous studies.Comment: 9 pages, 10 figures, Accepted to Ap

    Muon anomalous magnetic moment from effective supersymmetry

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    We present a detailed analysis on the possible maximal value of the muon (g-2) (= 2 a_mu) within the context of effective SUSY models with R parity conservation. First of all, the mixing among the second and the third family sleptons can contribute at one loop level to the a_mu(SUSY) and tau -> mu gamma simultaneously. One finds that the a_mu(SUSY) can be as large as (10-20)*10^-10 for any tan beta, imposing the upper limit on the tau -> mu gamma branching ratio. Furthermore, the two-loop Barr-Zee type contributions to a_mu(SUSY) can be significant for large tan beta, if a stop is light and mu and A_t are large enough (O(1) TeV). In this case, it is possible to have a_mu(SUSY) upto O(10)*10^-10 without conflicting with tau -> l gamma. We conclude that the possible maximal value for a_mu(SUSY) is about 20*10^-10 for any tan beta. Therefore the BNL experiment on the muon a_mu can exclude the effective SUSY models only if the measured deviation is larger than \sim 30*10^-10.Comment: 10 pages, 3 figure

    A numerical study of diffusive shock acceleration of cosmic rays in supernova shocks

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    The evolution of the energy spectrum of cosmic rays accelerated by the first order Fermi mechanism, by a supernova remnant shock wave, including adiabatic deceleration effects behind the front, is carried out by means of a time-dependent numerical code. The calculations apply to the adiabatic stage (or Sedov stage) of the supernova explosion, and the energetic particle spectrum is calculated in the test particle limit (i.e., the back reaction of the cosmic rays on the flow is not included). The particles are injected mono-energetically at the shock. The radial distribution, The radial distribution, and the spectrum of the accelerated and decelerated particles is shown

    Contribution of b→sggb \to sgg through the QCD anomaly in exclusive decays B±→(η′,η)(K±,K∗±)B^{\pm}\to (\eta^{\prime},\eta)(K^{\pm}, K^{*\pm}) and B0→(η′,η)(K0,K∗0)B^{0}\to (\eta^{\prime},\eta)(K^{0},K^{*0})

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    We compute the decay rates for the exclusive decays B±→(η′,η)(K±,K∗±)B^{\pm} \to (\eta^{\prime},\eta) (K^{\pm}, K^{*\pm}) and B0→(η′,η)(K0,K∗0)B^{0}\to (\eta^{\prime},\eta) (K^{0}, K^{*0}) in a QCD-improved factorization framework by including the contribution from the process b→sgg→s(η′,η)b\to sgg \to s (\eta^{\prime}, \eta) through the QCD anomaly. This method provides an alternative estimate of the contribution b→sccˉ→s(η,η′)b \to s c\bar{c} \to s(\eta,\eta^\prime) to these decays as compared to the one using the intrinsic charm content of the η′\eta^{\prime} and η\eta mesons determined through the decays J/ψ→(η,η′,ηc)γJ/\psi \to (\eta,\eta^\prime ,\eta_c) \gamma. The resulting branching ratios are compared with the CLEO data on B±→η′K±B^{\pm} \to \eta^{\prime} K^{\pm} and B0→η′K0B^{0} \to \eta^{\prime} K^{0} and predictions are made for the rest.Comment: 16 pages including 4 postscript figures; uses epsfig. The most recent branching ratios from CLEO, ref. [5], are taken into account. The theory part is unchange
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