847 research outputs found

    Couplings of heavy hadrons with soft pions from QCD sum rules

    Get PDF
    We estimate the couplings in the Heavy Hadron Chiral Theory (HHCT) lagrangian from the QCD sum rules in an external axial field. We take into account the perturbative correction to the meson correlator in the infinite mass limit. With the perturbative correction and three successive power corrections, the meson correlator in an axial field becomes one of the best known correlators. In spite of this, the corresponding sum rule is not very stable. It yields the result g_1 F^2/(380MeV)^3 = 0.1 - 0.2, where F^2 = f_M^2 m/4 = (380MeV)^3 is the central value of the heavy meson decay constant with the perturbative correction. This result is surprisingly low as compared with the constituent quark model estimate g_1 = 0.75. The sum rules for g_{2,3} following from nondiagonal Sigma-Sigma and diagonal Lambda-Sigma baryon correlators in an external axial field suggest g_{2,3} = 0.4 - 0.7, while diagonal Sigma-Sigma and nondiagonal Lambda-Sigma baryon sum rules have too large uncertainties.Comment: 15 pages, LaTeX2e, 6 ps figures include

    Geochemical aspect of impact cratering: Studies in Vernadsky Institute

    Get PDF
    Studies of the geochemical effects of impact cratering at the Vernadsky Institute in collaboration with the Institute of Dynamics of Geospheres, Moscow State University, Leningrad State University, and some other institutions were fulfilled by several approaches. At the initial stage, three approaches were used: (1) experimental studies of high-temperature vaporization of geological materials (basalts, granites, and so on) in vacuum that was considered as a model of behavior of impact melt and vapor; (2) search of impact-induced geochemical effects in the rock from terrestrial impact craters; and (3) studies of samples of lunar regolith. The next stage of the studies included experiments on quasi-equilibrium vaporization of geological material in Knudsen cells. The results of this investigation are discussed

    Two -loop O(GFMH2)O(G_F{M_H}^2) radiative corrections to the Higgs decay width H→γγH \to \gamma \gamma for large Higgs boson masses

    Full text link
    This note is devoted to the calculation of the two-loop O(GFMH2)O(G_F {M_H}^2) radiative corrections to the Higgs decay width H→γγH \to \gamma \gamma for large values of the Higgs boson mass MHM_H within the Minimal Standard Model. The use of the Equivalence Theorem makes it possible to reduce the problem to the consideration of the physical Higgs boson field and the Goldstone bosons w+,w−,zw^{+},w^{-},z. We present analytical results for the various two- and three-particle absorptive parts of two-loop contributions, using dispersive techniques, analytic results for all but one of the dispersive contributions. The typical size of the correction is ∼ 30\sim ~30 percent for a Higgs boson mass of order 1 TeV1~TeV.Comment: 21 pages, 7 uuencoded figure

    Sudy of the Propagation of Decimeter Radiowaves in the Atmosphere of Venus with the Aid of AIS ''venera 4''

    Get PDF
    Radio wave propagation in Venus atmosphere based on approximating inhomogeneity of refractivit
    • …
    corecore