1,220 research outputs found
and neutrino mass matrix with an approximate flavor symmetry
For a neutrino mass matrix whose texture has an approximate flavor symmetry
and where one has near degenerate neutrino mass, it is shown that the
tribimaximal values for atmospheric angle and solar
angle can be maintained even when the reactor angle
. The non zero implies approximate
symmetry instead of
symmetry.Comment: 13 pages,2 figures, Published in JHE
On the branching ratio of the "second class" tau --> eta' pi nu_tau decay
We present an assessment of the standard model expectations for the branching
ratio of the isotopic spin and G-parity violating decay tau --> eta' pi nu_tau.
The estimate is based on a vector and scalar meson dominance parametrization of
the relevant form factors, that explicitly accounts for pi^0-eta-eta' mixing.
The numerical results obtained in this framework indicate a branching ratio one
order of magnitude (or more) below the current experimental limit, and suggest
the possibility of evidencing some novel interaction in high statistics studies
of this decay.Comment: 8 page
Dirac equation for quasi-particles in graphene and quantum field theory of their Coulomb interaction
There is evidence for existence of massless Dirac quasi-particles in
graphene, which satisfy Dirac equation in (1+2) dimensions near the so called
Dirac points which lie at the corners at the graphene's brilluoin zone. We
revisit the derivation of Dirac equation in (1+2) dimensions obeyed by
quasiparticles in graphene near the Dirac points. It is shown that parity
operator in (1+2) dimensions play an interesting role and can be used for
defining "conserved" currents resulting from the underlying Lagrangian for
Dirac quasi-particles in graphene which is shown to have U_{A}(1)*U_{B}(1)
symmetry. Further the quantum field theory (QFT) of Coulomb interaction of 2D
graphene is developed and applied to vacuum polarization and electron self
energy and the renormalization of the effective coupling g of this interaction
and Fermi velocity which has important implications in the
renormalization group analysis of g and v_{f}.Comment: 10 pages, some typos have been corrected, some references have been
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