90,826 research outputs found
New Lepton Family Symmetry and Neutrino Tribimaximal Mixing
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 to
We consider the effective Hamiltonian of four quark operators in the Standard
Model in the exclusive and quasi-inclusive decays of the type , , where contains a single Kaon. Working
in the factorization assumption we find that the four quark operators can
account for the recently measured exclusive decays
and for appropriate choice of form factors but cannot explain the
large quasi-inclusive rate.Comment: Calculation of added and the correct BSW form factors
have been used. Latex 13 papges, 1 figur
New Parametrization of Neutrino Mixing Matrix
Global fits to neutrino oscillation data are compatible with tri-bimaximal
mixing pattern, which predicts and . We propose here to
parametrize the tri-bimaximal mixing matrix by its hermitian
generator using the exponential map. Then we use the exponential map
to express the deviations from tri-bimaximal pattern by deriving the hermitian
matrices and . 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
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
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 decays and discuss the possibility of measuring it
experimentally. For the spin-1 particles case, we study CP violation in the
decays of to octet baryon pairs. We show that these decays can
be used to put stringent constraints on the electric dipole moments of
, and .Comment: 14p, OZ-93/22, UM-93/89, OITS 51
Invisible Higgs boson, continuous mass fields and unHiggs mechanism
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
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 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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