82,990 research outputs found
Group and Tri-bimaximal Neutrino Mixing -- A Renormalizable Model
The tetrahedron group has been widely used in studying neutrino mixing
matrix. It provides a natural framework of model building for the tri-bimaximal
mixing matrix. In this class of models, it is necessary to have two Higgs
fields, and , transforming under as 3 with one of them
having vacuum expectation values for the three components to be equal and
another having only one of the components to be non-zero. These specific vev
structures require separating and from communicating with each
other. The clash of the different vev structures for and is the
so called sequestering problem. In this work, I show that it is possible to
construct renormalizable supersymmetric models producing the tri-bimaximal
neutrino mixing with no sequestering problem.Comment: 4 page
Suitability of A_4 as a Family Symmetry in Grand Unification
In the recent successful applications of the non-Abelian discrete symmetry
A_4 to the tribimaximal mixing of neutrinos, lepton doublets and singlets do
not transform in the same way. It appears thus to be unsuitable as a family
symmetry in grand unification. A simple resolution of this dilemma is proposed.Comment: 6 pages, no figur
Effects of Initial Stance of Quadruped Trotting on Walking Stability
It is very important for quadruped walking machine to keep its stability in
high speed walking. It has been indicated that moment around the supporting
diagonal line of quadruped in trotting gait largely influences walking
stability. In this paper, moment around the supporting diagonal line of
quadruped in trotting gait is modeled and its effects on body attitude are
analyzed. The degree of influence varies with different initial stances of
quadruped and we get the optimal initial stance of quadruped in trotting gait
with maximal walking stability. Simulation results are presented. Keywords:
quadruped, trotting, attitude, walking stability
Seesaw Options for Three Neutrinos
The seesaw mechanism for three neutrinos is discussed, clarifying the
situation where the seesaw texture results in three approximately zero mass
eigenvalues. The true underlying mechanism is shown to be just the
(or ) seesaw, which explains why there could be large mixing. However,
these zeroes cannot occur naturally, unless there is a conserved symmetry, i.e.
lepton number , either global or gauged, which is softly or spontaneously
broken at the TeV scale. We discuss in particular the case where the three
heavy singlet neutrinos have .Comment: Latex, 11 Pages with 1 figure. Some minor modifications and a
reference adde
-dimensional regular black holes with nonlinear electrodynamics sources
On the basis of two requirements: the avoidance of the curvature singularity
and the Maxwell theory as the weak field limit of the nonlinear
electrodynamics, we find two restricted conditions on the metric function of
-dimensional regular black hole in general relativity coupled with
nonlinear electrodynamics sources. By the use of the two conditions, we obtain
a general approach to construct -dimensional regular black holes. In
this manner, we construct four -dimensional regular black holes as
examples. We also study the thermodynamic properties of the regular black holes
and verify the first law of black hole thermodynamics.Comment: 13 pages, 4 figures. in press in PL
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