5,626 research outputs found

    Inertia of Heat in Advective Accretion Disks around Kerr Black Holes

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    In the innermost region of the advective accretion disk orbiting a black hole of high spin, the inertia of heat stored in the accreting gas is comparable to that of the gas rest mass itself. Accounting for this effect, we derive additional terms in the disk structure equations, and show that the heat inertia plays a significant role in the global energy conservation and dynamics of accretion in the relativistic advective disks.Comment: 6 pages, Latex, submitted to ApJ

    Once more on extra quark-lepton generations and precision measurements

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    Precision measurements of ZZ-boson parameters and WW-boson and tt-quark masses put strong constraints on non SU(2)×U(1)SU(2)\times U(1) singlet New Physics. We demonstrate that one extra generation passes electroweak constraints even when all new particle masses are well above their direct mass bounds.Comment: Dedicated to L.B. Okun's 80th birthda

    On the numerical closeness of the effective phenomenological electroweak mixing angle θ\theta and the \MS parameter θ^\hat\theta

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    It happens that s2s^2 and s^2\hat s^2 are equal with 0.1% accuracy, though they are split by radiative corrections and a natural estimate for their difference is 1%. This degeneracy occurs only for mtm_t value close to 170\GeV, so no deep physical reason can be attributed to it. However, another puzzle of the Standard Model, the degeneracy of s_\Eff^2 and s2s^2, is not independent of the previous one since a good physical reason exists for s_\Eff^2 and s^2\hat s^2 degeneracy. We present explicit formulas which relate these three angles.Comment: 10 pages, latex, 3 figures included; published on MPLA. A few numerical estimates are improved; journal-ref is adde

    New global stability estimates for the Gel'fand-Calderon inverse problem

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    We prove new global stability estimates for the Gel'fand-Calderon inverse problem in 3D. For sufficiently regular potentials this result of the present work is a principal improvement of the result of [G. Alessandrini, Stable determination of conductivity by boundary measurements, Appl. Anal. 27 (1988), 153-172]

    Two-dimensional algebro-geometric difference operators

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    A generalized inverse problem for a two-dimensional difference operator is introduced. A new construction of the algebro-geometric difference operators of two types first considered by I.M.Krichever and S.P.Novikov is proposedComment: 11 pages; added references, enlarged introduction, rewritten abstrac

    Geometry and Statistics of Cosmic Microwave Polarization

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    Geometrical and statistical properties of polarization of CMB are analyzed. Singular points of the vector field which describes CMB polarization are found and classified. Statistical distribution of the singularities is studied. A possible signature of tensor perturbations in CMB polarization is discussed. For a further analysis of CMB statistics Minkowski functionals are used, which present a technically simple method to search for deviations from a Gaussian distribution.Comment: 37 pages, 5 figures, submitted in Int.J.Mod.Phys.

    Mass of the higgs versus fourth generation masses

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    The predicted value of the higgs mass mHm_H is analyzed assuming the existence of the fourth generation of leptons (N,EN, E) and quarks (U,DU, D). The steep and flat directions are found in the five-dimensional parameter space: mHm_H, mUm_U, mDm_D, mNm_N, mEm_E. The LEPTOP fit of the precision electroweak data is compatible (in particular) with mH∼300m_H \sim 300 GeV, mN∼50m_N \sim 50 GeV, mE∼100m_E \sim 100 GeV, mU+mD∼500m_U +m_D \sim 500 GeV, and ∣mU−mD∣∼75|m_U -m_D| \sim 75 GeV. The quality of fits drastically improves when the data on b- and c-quark asymmetries and new NuTeV data on deep inelastic scattering are ignored.Comment: 8 pages, 4 figure

    Diagrammatic calculation of energy spectrum of quantum impurity in degenerate Bose-Einstein condensate

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    In this paper we considered a quantum particle moving through delute Bose-Einstein condensate at zero temperature. In our formulation the impurity particle interacts with the gas of uncoupled Bogoliubov's excitations. We constructed the perturbation theory for the Green's function of the impurity particle with respect to the impurity-condensate interaction employing the coherent-state path integral approach. The perturbative expansion for the Green's function is resumed into the expansion for its poles with the help of the diagrammatic technique developed in this work. The dispersion relation for the impurity clothed by condensate excitations is obtained and effective mass is evaluated beyond the Golden rule approximation
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