6,115 research outputs found
B meson decays to baryons in the diquark model
We study B meson decays to two charmless baryons in the diquark model,
including strong and electroweak penguins as well as the tree operators. It is
shown that penguin operators can enhance \bar{B} \to \Bb_s \bar{\Bb}
considerably, but affect \bar{B} \to \Bb_1 \bar{\Bb}_2 only slightly, where
\Bb_{(1,2)} and \Bb_s are non-strange and strange baryons, respectively.
The dependence of the decay rates due to tree-penguin interference is
illustrated. In principle, some of the \Bb_s \bar{\Bb} modes could dominate
over \Bb_1 \bar{\Bb}_2 for , but in general the effect is
milder than their mesonic counterparts. This is because the operator can
only produce vector but not scalar diquarks, while the opposite is true for
and . Predictions from diquark model are compared to those from the
sum rule calculation. The decays \bar{B} \to \Bb_s \bar{\Bb}_s and inclusive
baryonic decays are also discussed.Comment: 9 pages, 6 figures, Revte
Neutrino Masses in a 5D TeV Unification Model
We study the generation of neutrino masses in the electroweak
unified theory in spacetime. By appropriate
orbifolding, the bulk symmetry is broken into
at one of the fixed points, where the quarks reside. The leptons form
triplets, localized at the other symmetric fixed point. The fermion masses
arise from the bulk Higgs sector containing a triplet and an anti-sextet. We
construct neutrino Majorana masses via 1-loop quantum corrections by adding a
parity odd bulk triplet scalar. No right-handed neutrino is needed. The
neutrino mass matrix is of the inverted hierarchy type. We show that the model
can easily accommodate the bi-large mixing angle solution favored by the recent
neutrino experiments without much fine tuning of parameters. The constraints
from \mu\ra 3e transition and neutrinoless double beta decays are discussed.Comment: 14 pages, 4 figure
Bulk Higgs Boson Decays in Brane Localized Gravity
We embed the Standard Model in the Randall-Sundrum model of 5 dimensional
brane localized gravity. The SM gauge and chiral fermion fields are restricted
on the 4D visible brane whereas the Higgs and the right-handed neutrino are
assumed to be 5D bulk fields. We calculate the effective couplings of the
lowest mass Higgs field to the SM fermions and to the gauge bosons and find
that the couplings are enhanced. Furthermore, the invisible decay width of a
bulk Higgs of mass 150 GeV is shown to be large.Comment: 14 pages, 2 postscript figures, minor typos corrected, two references
added, to appear in Physics Letters
QCD Corrections to and Exclusive Decay
The short distance QCD corrections to are calculated in
the leading logarithmic approximation. The equivalence of operator basis
reduction for S-matrix elements by using the equations of motion or by proving
a low energy theorem is discussed. We apply the above results to the exclusive
decay. The branching ratio of this decay is found to be
in the Standard Model. We also found that QCD corrections
modify considerably the ratio between CP-even and CP-odd two-photon amplitudes.Comment: revtex, 15 pages, 2 figures; revised version with corrections from
electroweak penguin discussed, the conclusion remains unchange
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