1,710 research outputs found
Effective operator contributions to the oblique parameters
We present a model and process independent study of the contributions from
non-Standard Model physics to the oblique parameters S, T and U. We show that
within an effective lagrangian parameterization the expressions for the oblique
parameters in terms of observables are consistent, while those in terms of the
vector-boson vacuum polarization tensors are ambiguous. We obtain the
constraints on the scale of new physics derived from current data on S, T and U
and note that deviations in U from its Standard Model value would favor a
scenario where the underlying physics does not decouple.Comment: 13 pages, RevTe
Sea Contributions to Spin 1/2 Baryon Structure, Magnetic Moments, and Spin Distribution
We treat the baryon as a composite system made out of a \lq\lq core" of three
quarks (as in the standard quark model) surrounded by a \lq\lq sea" (of gluons
and -pairs) which is specified by its total quantum numbers like
flavor, spin and color. Specifically, we assume the sea to be a flavor octet
with spin 0 or 1 but no color. The general wavefunction for spin 1/2 baryons
with such a sea component is given. Application to the magnetic moments is
considered. Numerical analysis shows that a scalar (spin 0) sea with an
admixture of a vector (spin 1) sea can provide very good fits to the magnetic
moment data {\em using experimental errors}. Our best fit automatically gives
for neutron beta decay in agreement with data. This fit also gives
reasonable values for the spin distributions of the proton and neutron.Comment: 24 pages, REVTEX. References modifie
A priori mixed hadrons, hyperon non-leptonic decays, and the |\Delta I|=1/2 rule
The |\Delta I|=1/2 rule in non-leptonic decays of hyperons can be naturally
understood by postulating a priori mixed physical hadrons, along with the
isospin invariance of the responsible transition operator. It is shown that
this operator can be identified with the strong interaction Yukawa hamiltonian.Comment: Workshops on Particles and Fields and Phenomenology of Fundamental
Interactions. J. C. D'Olivo, A. Fernandez, and M. A. Perez, Ed
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