28,174 research outputs found

    Neutrino Masses and Mixing, Quark-lepton Symmetry and Strong Right-handed Neutrino Hierarchy

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    Assuming the same form of all mass matrices as motivated by quark-lepton symmetry, we discuss conditions under which bi-large mixing in the lepton sector can be obtained with a minimal amount of fine tuning requirements for possible models. We assume hierarchical mass matrices, dominated by the 3-3 element, with off-diagonal elements much smaller than the larger neighboring diagonal element. Characteristic features of this scenario are strong hierarchy in masses of right-handed neutrinos, and comparable contributions of both lighter right-handed neutrinos to the resulting left-handed neutrino Majorana mass matrix. Due to obvious quark lepton symmetry, this approach can be embedded into grand unified theories. The mass of the lightest neutrino does not depend on details of a model in the leading order. The right-handed neutrino scale can be identified with the GUT scale in which case the mass of the lightest neutrino is given as (m_{top}^2/M_{GUT}) |U_{\tau 1}|^2.Comment: 7 page

    Possible evidence of extended objects inside the proton

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    Recent experimental determinations of the Nachtmann moments of the inelastic structure function of the proton F2p(x, Q**2), obtained at Jefferson Lab, are analyzed for values of the squared four-momentum transfer Q**2 ranging from ~ 0.1 to ~ 2 (GeV/c)**2. It is shown that such inelastic proton data exhibit a new type of scaling behavior and that the resulting scaling function can be interpreted as a constituent form factor consistent with the elastic nucleon data. These findings suggest that at low momentum transfer the inclusive proton structure function originates mainly from the elastic coupling with extended objects inside the proton. We obtain a constituent size of ~ 0.2 - 0.3 fm.Comment: 1 reference adde

    Numerical indications of a q-generalised central limit theorem

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    We provide numerical indications of the qq-generalised central limit theorem that has been conjectured (Tsallis 2004) in nonextensive statistical mechanics. We focus on NN binary random variables correlated in a {\it scale-invariant} way. The correlations are introduced by imposing the Leibnitz rule on a probability set based on the so-called qq-product with q1q \le 1. We show that, in the large NN limit (and after appropriate centering, rescaling, and symmetrisation), the emerging distributions are qeq_e-Gaussians, i.e., p(x)[1(1qe)β(N)x2]1/(1qe)p(x) \propto [1-(1-q_e) \beta(N) x^2]^{1/(1-q_e)}, with qe=21qq_e=2-\frac{1}{q}, and with coefficients β(N)\beta(N) approaching finite values β()\beta(\infty). The particular case q=qe=1q=q_e=1 recovers the celebrated de Moivre-Laplace theorem.Comment: Minor improvements and corrections have been introduced in the new version. 7 pages including 4 figure

    Quasiclassical Equations of Motion for Nonlinear Brownian Systems

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    Following the formalism of Gell-Mann and Hartle, phenomenological equations of motion are derived from the decoherence functional formalism of quantum mechanics, using a path-integral description. This is done explicitly for the case of a system interacting with a ``bath'' of harmonic oscillators whose individual motions are neglected. The results are compared to the equations derived from the purely classical theory. The case of linear interactions is treated exactly, and nonlinear interactions are compared using classical and quantum perturbation theory.Comment: 24 pages, CALT-68-1848 (RevTeX 2.0 macros

    Orbifold Family Unification

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    We study the possibility of complete family unification in higher-dimensional space-time. Three families of matters in SU(5) grand unified theory are derived from a single bulk multiplet of SU(N) gauge group (N >= 9) in the framework of S^1/Z_2 orbifold models. In the case of the direct orbifold breaking down to the standard model gauge group, there are models in which bulk fields from a single multiplet and a few brane fields compose three families of quarks and leptons.Comment: Comments added, version to appear in Physical Review D (v3); References added (v2); 19 pages (v1

    Reactor antineutrino spectra and their application to antineutrino-induced reactions. II

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    The antineutrino and electron spectra associated with various nuclear fuels are calculated. While there are substantial differences between the spectra of different uranium and plutonium isotopes, the dependence on the energy and flux of the fission-inducing neutrons is very weak. The resulting spectra can be used for the calculation of the antineutrino and electron spectra of an arbitrary nuclear reactor at various stages of its refueling cycle. The sources of uncertainties in the spectrum are identified and analyzed in detail. The exposure time dependence of the spectrum is also discussed. The averaged cross sections of the inverse neutron β decay, weak charged and neutral-current-induced deuteron disintegration, and the antineutrino-electron scattering are then evaluated using the resulting ν̅_e spectra. [RADIOACTIVITY, FISSION 235U, 238U, (^239)Pu, (^240)Pu, (^241)Pu, antineutrino and electron spectra calculated. σ for ν̅ induced reactions analyzed.

    Statistical Mechanics of Relativistic One-Dimensional Self-Gravitating Systems

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    We consider the statistical mechanics of a general relativistic one-dimensional self-gravitating system. The system consists of NN-particles coupled to lineal gravity and can be considered as a model of NN relativistically interacting sheets of uniform mass. The partition function and one-particle distitrubion functions are computed to leading order in 1/c1/c where cc is the speed of light; as cc\to\infty results for the non-relativistic one-dimensional self-gravitating system are recovered. We find that relativistic effects generally cause both position and momentum distribution functions to become more sharply peaked, and that the temperature of a relativistic gas is smaller than its non-relativistic counterpart at the same fixed energy. We consider the large-N limit of our results and compare this to the non-relativistic case.Comment: latex, 60 pages, 22 figure

    Higher Order Stability of a Radiatively Induced 220 GeV Higgs Mass

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    The effective potential for radiatively broken electroweak symmetry in the single Higgs doublet Standard Model is explored to four sequentially subleading logarithm-summation levels (5-loops) in the dominant Higgs self-interaction couplant λ\lambda. We augment these results with all contributing leading logarithms in the remaining large but sub-dominant Standard Model couplants (t-quark, QCD and SU(2)U(1)SU(2)\otimes U(1) gauge couplants) as well as next to leading logarithm contributions from the largest of these, the t-quark and QCD couplants. Order-by-order stability is demonstrated for earlier leading logarithm predictions of an order 220 GeV Higgs boson mass in conjunction with fivefold enhancement of the value for λ\lambda over that anticipated from conventional spontaneous symmetry breaking.Comment: revtex, 6 pages. Analysis and text is expanded in revised versio
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