91,534 research outputs found

    New Lepton Family Symmetry and Neutrino Tribimaximal Mixing

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    The newly proposed finite symmetry Sigma(81) is applied to the problem of neutrino tribimaximal mixing. The result is more satisfactory than those of previous models based on A_4 in that the use of auxiliary symmetries (or mechanisms) may be avoided. Deviations from the tribimaximal pattern are expected, but because of its basic structure, only tan^2 (theta_12) may differ significantly from 0.5 (say 0.45) with sin^2 (2 theta_23) remaining very close to one, and theta_13 very nearly zero.Comment: 8 pages, no figur

    Quasi-Inclusive and Exclusive decays of BB to η\eta'

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    We consider the effective Hamiltonian of four quark operators in the Standard Model in the exclusive and quasi-inclusive decays of the type BK()ηB\to K^{(*)} \eta^{\prime}, BηXsB\to \eta' X_s, where XsX_s contains a single Kaon. Working in the factorization assumption we find that the four quark operators can account for the recently measured exclusive decays Bη(η)KB\to \eta^{\prime}(\eta) K and BKπB\to K \pi for appropriate choice of form factors but cannot explain the large quasi-inclusive rate.Comment: Calculation of BKπB \to K \pi added and the correct BSW form factors have been used. Latex 13 papges, 1 figur

    New Parametrization of Neutrino Mixing Matrix

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    Global fits to neutrino oscillation data are compatible with tri-bimaximal mixing pattern, which predicts θ23=π4,θ12=sin1(13)\theta_{23} = \frac{\pi}{4}, \theta_{12} = \sin^{-1} (\frac{1}{\sqrt{3}}) and θ13=0\theta_{13} = 0. We propose here to parametrize the tri-bimaximal mixing matrix VTBMV_{TBM} by its hermitian generator HTBMH_{TBM} using the exponential map. Then we use the exponential map to express the deviations from tri-bimaximal pattern by deriving the hermitian matrices Hz=0H_{z=0} and H1H_1. These deviations might come from the symmetry breaking of the neutrino and charged lepton sectors.Comment: 10 pages, no figures, correted minor typo

    A covariant entropy conjecture on cosmological dynamical horizon

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    We here propose a covariant entropy conjecture on cosmological dynamical horizon. After the formulation of our conjecture, we test its validity in adiabatically expanding universes with open, flat and closed spatial geometry, where our conjecture can also be viewed as a cosmological version of the generalized second law of thermodynamics in some sense.Comment: JHEP style, 9 pages, 1 figure, typos corrected, accepted for publication in JHE

    CP Violation in Fermion Pair Decays of Neutral Boson Particles

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    We study CP violation in fermion pair decays of neutral boson particles with spin 0 or 1. We study a new asymmetry to measure CP violation in η,KLμ+μ\eta, K_L \rightarrow \mu^+\mu^- decays and discuss the possibility of measuring it experimentally. For the spin-1 particles case, we study CP violation in the decays of J/ψJ/\psi to SU(3)SU(3) octet baryon pairs. We show that these decays can be used to put stringent constraints on the electric dipole moments of Λ\Lambda, Σ\Sigma and Ξ\Xi.Comment: 14p, OZ-93/22, UM-93/89, OITS 51

    Invisible Higgs boson, continuous mass fields and unHiggs mechanism

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    We explore the consequences of an electroweak symmetry breaking sector which exhibits approximately scale invariant dynamics -- i.e., nontrivial fixed point behavior, as in unparticle models. One can think of an unHiggs as a composite Higgs boson with a continuous mass distribution. We find it convenient to represent the unHiggs in terms of a Kallen-Lehmann spectral function, from which it is simple to verify the generation of gauge boson and fermion masses, and unitarization of WW scattering. We show that a spectral function with broad support, which corresponds to approximate fixed point behavior over an extended range of energy, can lead to an effectively invisible Higgs particle, whose decays at LEP or LHC could be obscured by background.Comment: 8 page

    Covariant entropy conjecture and concordance cosmological models

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    Recently a covariant entropy conjecture has been proposed for dynamical horizons. We apply this conjecture to concordance cosmological models, namely, those cosmological models filled with perfect fluids, in the presence of a positive cosmological constant. As a result, we find this conjecture has a severe constraint power. Not only does this conjecture rule out those cosmological models disfavored by the anthropic principle, but also it imposes an upper bound 106010^{-60} on the cosmological constant for our own universe, which thus provides an alternative macroscopic perspective for understanding the long-standing cosmological constant problem.Comment: 10 pages, 1 figure, JHEP style, references added, published versio
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