9,935 research outputs found
Comment on "PT Symmetry as a Generalization of Hermiticity" [arXiv:1002.2676]
We notice that the general PT-symmetric Hamiltonian matrix(N=2) having 6-real
parameters fails to reproduce one parameter PT-symmetric matrix.Comment: Title unchanged ,one ref [5] added . Abstract changed . All the
previous matrices have been changed consideing the ref[5
Neutrino mass generation in the SO(4) model
Generation of neutrino mass in SO(4) model is proposed here. The algebraic
structure of SO(4) is same as to that of . It is
shown that the spontaneous symmetry breaking results three massive as well as
three massless gauge bosons. The standard model theory according to which there
exist three massive gauge bosons and a massless one is emerged from this model.
In the framework of a small Dirac neutrino mass is
derived. It is also shown that such mass term may vanish with a special choice.
The Majorana mass term is not considered here and thus in this model the
neutrino mass does not follow seesaw structure.Comment: 7 pages, no figur
Neutrino Mass and New Physics
We review the present state of and future outlook for our understanding of
neutrino masses and mixings. We discuss what we think are the most important
perspectives on the plausible and natural scenarios for neutrinos and what may
have the most promise to throw light on the flavor problem of quarks and
leptons. We focus on the seesaw mechanism which fits into the big picture of
particle physics such as supersymmetry and grand unification providing a
unified approach to flavor problem of quarks and leptons. We argue that in
combination with family symmetries, this may be at the heart of a unified
understanding of flavor puzzle. We also discuss other new physics ideas such as
neutrinos in models with extra dimensions and possible theoretical implications
of sterile neutrinos. We outline some tests for the various schemes.Comment: 90 pages and 9 figures; With permission from the Annual Review of
Nuclear and Particle Science. Final version of this material is scheduled to
appear in the Annual Review of Nuclear and Particle Science Vol. 56, to be
published in November 2006 by Annual Reviews (http://www.annualreviews.org);
some references and parts of text update
Minimal Pati-Salam Model from String Theory Unification
We provide what we believe is the minimal three family SUSY
and conformal Pati-Salam Model from type IIB superstring theory. This
orbifolded AdS model has long lived protons and has potential
phenomenological consequences for LHC.Comment: 8 page
On Neutrino Masses and Family Replication
The old issue of why there are more than one family of quarks and leptons is
reinvestigated with an eye towards the use of anomaly as a tool for
constraining the number of families. It is found that, by assuming the
existence of right-handed neutrinos (which would imply that neutrinos will have
a mass) and a new chiral SU(2) gauge theory, strong constraints on the number
of families can be obtained. In addition, a model, based on that extra SU(2),
is constructed where it is natural to have one "very heavy" fourth neutrino and
three almost degenerate light neutrinos whose masses are all of the Dirac type.Comment: RevTex, 12 pages with 1 figure, minor changes to the text and added
acknowledgment
THE DYNAMIC EFFECTS OF U.S. FOOD AID
Food Security and Poverty, International Development,
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