3,842 research outputs found

    Higgs Mass in the Standard Model from Coupling Constant Reduction

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    Plausible interrelations between parameters of the standard model are studied. The empirical value of the top quark mass, when used in the renormalization group equations, suggests that the ratio of the colour SU(3) gauge coupling g3g_3, and the top coupling gtg_t is independent of the renormalization scale. On the other hand, variety of top-condensate models suggest that the Higgs self-coupling λ\lambda is proportional to gt2g_t^2. Invoking the requirement that the ratio λ(t)/gt2(t)\lambda(t)/g_t^2(t) is independent of the renormalization scale tt, fixes the Higgs mass. The pole mass of the Higgs [which differs from the renormalization group mass by a few percent] is found to be ∼154\sim 154 GeV for the one-loop equations and ∼148\sim 148 GeV for the two-loop equations.Comment: 17 pages RevTeX including 7 figure

    General relativistic gravitational field of a rigidly rotating disk of dust: Solution in terms of ultraelliptic functions

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    In a recent paper we presented analytic expressions for the axis potential, the disk metric, and the surface mass density of the global solution to Einstein's field equations describing a rigidly rotating disk of dust. Here we add the complete solution in terms of ultraelliptic functions and quadratures.Comment: 5 pages, published in 1995 [Phys. Rev. Lett. 75 (1995) 3046

    1/N_c Corrections to the Hadronic Matrix Elements of Q_6 and Q_8 in K --> pi pi Decays

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    We calculate long-distance contributions to the amplitudes A(K^0 --> pi pi, I) induced by the gluon and the electroweak penguin operators Q_6 and Q_8, respectively. We use the 1/N_c expansion within the effective chiral lagrangian for pseudoscalar mesons. In addition, we adopt a modified prescription for the identification of meson momenta in the chiral loop corrections in order to achieve a consistent matching to the short-distance part. Our approach leads to an explicit classification of the loop diagrams into non-factorizable and factorizable, the scale dependence of the latter being absorbed in the low-energy coefficients of the effective theory. Along these lines we calculate the one-loop corrections to the O(p^0) term in the chiral expansion of both operators. In the numerical results, we obtain moderate corrections to B_6^(1/2) and a substantial reduction of B_8^(3/2).Comment: 32 pages, LaTeX, 8 eps figures. One reference added, to appear in Phys. Rev.

    A relativistic calculation of super-Hubble suppression of inflation with thermal dissipation

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    We investigated the evolution of the primordial density perturbations produced by inflation with thermal dissipation. A full relativistic analysis on the evolution of initial perturbations from the warm inflation era to a radiation-dominated universe has been developed. The emphasis is on tracking the ratio between the adiabatic and the isocurvature mode of the initial perturbations. This result is employed to calculate a testable factor: the super-Hubble suppression of the power spectrum of the primordial perturbations. We show that based on the warm inflation scenario, the super-Hubble suppression factor, ss, for an inflation with thermal dissipation is at least 0.5. This prediction does not depend on the details of the model parameters. If ss is larger than 0.5, it implies that the friction parameter Γ\Gamma is larger than the Hubble expansion parameter HH during the inflation era.Comment: 22 pages, 3 figures, use RevTex, accepted by Class. Quant. Gra

    General Relativistic Description of the Observed Galaxy Power Spectrum: Do We Understand What We Measure?

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    We extend the general relativistic description of galaxy clustering developed in Yoo, Fitzpatrick, and Zaldarriaga (2009). For the first time we provide a fully general relativistic description of the observed matter power spectrum and the observed galaxy power spectrum with the linear bias ansatz. It is significantly different from the standard Newtonian description on large scales and especially its measurements on large scales can be misinterpreted as the detection of the primordial non-Gaussianity even in the absence thereof. The key difference in the observed galaxy power spectrum arises from the real-space matter fluctuation defined as the matter fluctuation at the hypersurface of the observed redshift. As opposed to the standard description, the shape of the observed galaxy power spectrum evolves in redshift, providing additional cosmological information. While the systematic errors in the standard Newtonian description are negligible in the current galaxy surveys at low redshift, correct general relativistic description is essential for understanding the galaxy power spectrum measurements on large scales in future surveys with redshift depth z>3. We discuss ways to improve the detection significance in the current galaxy surveys and comment on applications of our general relativistic formalism in future surveys.Comment: accepted for publication in Physical Review

    Neutrino masses and mixings

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    We propose a novel theoretical understanding of neutrino masses and mixings, which is attributed to the intrinsic vector-like feature of the regularized Standard Model at short distances. We try to explain the smallness of Dirac neutrino masses and the decoupling of the right-handed neutrino as a free particle. Neutrino masses and mixing angles are completely related to each other in the Schwinger-Dyson equations for their self-energy functions. The solutions to these equations and a possible pattern of masses and mixings are discussed.Comment: LaTex 11 page

    Anomalous Chiral Behavior in Quenched Lattice QCD

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    A study of the chiral behavior of pseudoscalar masses and decay constants is carried out in quenched lattice QCD with Wilson fermions. Using the modified quenched approximation (MQA) to cure the exceptional configuration problem, accurate results are obtained for pion masses as low as ≈\approx 200 MeV. The anomalous chiral log effect associated with quenched η′\eta' loops is studied in both the relation between mπ2m_{\pi}^2 vs. mqm_q and in the light-mass behavior of the pseudoscalar and axial vector matrix elements. The size of these effects agrees quantitatively with a direct measurement of the η′\eta' hairpin graph, as well as with a measurement of the topological susceptibility, thus providing several independent and quantitatively consistent determinations of the quenched chiral log parameter δ\delta. For β=5.7\beta=5.7 with clover-improved fermions (Csw=1.57)(C_{sw} =1.57) all results are consistent with δ=0.065±0.013\delta=0.065\pm 0.013 .Comment: 51 pages, 20 figures, Late

    Running-phase state in a Josephson washboard potential

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    We investigate the dynamics of the phase variable of an ideal underdamped Josephson junction in switching current experiments. These experiments have provided the first evidence for macroscopic quantum tunneling in large Josephson junctions and are currently used for state read-out of superconducting qubits. We calculate the shape of the resulting macroscopic wavepacket and find that the propagation of the wavepacket long enough after a switching event leads to an average voltage increasing linearly with time.Comment: 6 pages, 3 figure

    Thermodynamics of the superconducting state in Calcium at 200 GPa

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    The thermodynamic parameters of the superconducting state in Calcium under the pressure at 200 GPa were calculated. The Coulomb pseudopotential values (μ⋆\mu^{\star}) from 0.1 to 0.3 were taken into consideration. It has been shown, that the specific heat's jump at the critical temperature and the thermodynamic critical field near zero Kelvin strongly decrease with μ⋆\mu^{\star}. The dimensionless ratios r1≡ΔC(TC)/CN(TC)r_{1}\equiv \Delta C(T_{C})/C^{N}(T_{C}) and r2≡TCCN(TC)/HC2(0)r_{2}\equiv T_{C}C^{N}(T_{C})/H^{2}_{C}(0) significantly differ from the predictions based on the BCS model. In particular, r1r_{1} decreases from 2.64 to 1.97 with the Coulomb pseudopotential; whereas r2r_{2} increases from 0.140 to 0.157. The numerical results have been supplemented by the analytical approach.Comment: 7 pages, 6 figure

    Quenched Chiral Artifacts for Wilson-Dirac Fermions

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    We examine artifacts associated with the chiral symmetry breaking induced through the use of Wilson-Dirac fermions in lattice Monte Carlo computations. For light quark masses, the conventional quenched theory can not be defined using direct Monte Carlo methods due to the existence of nonintegrable poles in physical quantities. These poles are associated with the real eigenvalue spectrum of the Wilson-Dirac operator. We show how this singularity structure can be observed in the analysis of both QED in two dimensions and QCD in four dimensions.Comment: 32 pages (Latex) including 13 figures (EPS
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