70 research outputs found
Quantization and renormalization of the manifest left-right symmetric model of electroweak interactions
Quantization and renormalization of the left-right symmetric model is the
main purpose of the paper. First the model at tree level with a Higgs sector
containing one bidoublet and two triplets is precisely discussed. Then the
canonical quantization and Faddeev-Popov Lagrangian are carried out ('t Hooft
gauge). The BRST symmetry is discussed. Subsequently the on mass shell
renormalization is performed and, as a test of consistency, the renormalization
of the ZNiNj vertex is analyzed.Comment: 74 pages, 65 Postscript figures, submitted to Annals of Physic
The Minimal Extension of the SM and the Neutrino Oscillation Data
We study the simplest Standard Model estension with only one extra
right-handed neutrino. In this case there are two massless and two
massive neutrinos, and in principle both solar and atmospheric
anomalies can be described in two different scenarios, (scheme I)
and (scheme II). However, neither bi-maximal mixing nor the
dark matter problem are explained in this minimal extension. Only scheme II can
accommodate simultaneously maximal mixing for atmospheric neutrinos and the
small mixing angle MSW solution for the solar anomaly. This scenario can be
tested in the BOREXINO experiment.Comment: 9 pages, Presented by J. Gluza at the XXIII School of Theoretical
Physics, Ustron'99, Poland, September 15-22, 199
Neutrino oscillations beyond the Standard Model
We address the possible impact of New Physics on neutrino oscillation
experiments. This can modify the neutrino production, propagation and/or
detection, making the full cross section non-factorizable in general. Thus, for
example, the neutrino flux may not be properly described assuming an unitary
MNS matrix and/or neutrinos may propagate differently depending of their Dirac
or Majorana character. Interestingly enough, present limits on New Physics
still allow for observable effects at future neutrino experiments.Comment: 2 pages, 2 figures, Presented at the Neutrino 08 Conference,
Christchurch, New Zealand, May 25-31, 200
Confronting electroweak precision measurements with New Physics models
Precision experiments, such as those performed at LEP and SLC, offer us an
excellent opportunity to constrain extended gauge model parameters. To this
end, it is often assumed, that in order to obtain more reliable estimates, one
should include the sizable one--loop Standard Model (SM) corrections, which
modify the couplings as well as other observables. This conviction is
based on the belief that the higher order contributions from the ``extension
sector'' will be numerically small. However, the structure of higher order
corrections can be quite different when comparing the SM with its extension,
thus one should avoid assumptions which do not care about such facts. This is
the case for all models with . As an example, both the manifest
left-right symmetric model and the model, with an additional boson, are discussed and special
attention to the top contribution to is given. We conclude that
the only sensible way to confront a model with the experimental data is to
renormalize it self-consistently, if not, parameters which depend strongly on
quantum effects should be left free in fits, though essential physics is lost
in this way. We should note that arguments given here allow us to state that at
the level of loop corrections (indirect effects) there is nothing like a
``model independent global analysis'' of the data.Comment: 10 page
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