980 research outputs found
Neutrino mass patterns, R-parity violating supersymmetry and associated phenomenology
Motivated by the recent SuperKamiokande results on atmospheric neutrinos, we
incorporate massive neutrinos, with large angle oscillation between the second
and third generations, in a theory with R-parity violating supersymmetry. The
general features of such a theory are briefly reviewed. We emphasize its
testability through the observation of comparable numbers of muons and taus,
produced together with the W-boson, in decays of the lightest neutralino. A
distinctly measurable decay gap is another remarkable feature of such a
scenario.Comment: 7 pages, latex, talk delivered at the Discussion Meeting on Neutrino
Physics, Physical Research Laboratory, Ahmedabad, India, February 2-4, 199
Bilarge neutrino mixing in R-parity violating supersymmetry: the role of right-chiral neutrino superfields
We consider the possibility of neutrino mass generation in a supersymmetric
model where lepton number can be violated by odd units. The different patterns
of mixing in the quark and lepton sectors are attributed to the persence of
right-chiral neutrino superfields which (a) enter into Yukawa couplings via
non-renormalizable interaction with hidden sector fields, and (b) can violate
lepton number by odd units. Both of these features are shown to be the result
of some global quantum number which is violated when SUSY is broken in the
hidden sector. It is shown how such a scenario, together with all known
R-parity violating effects, can lead to neutrino masses and bilarge mixing via
seesaw as well as radiative mechanisms. Some sample values of the various
parameters involved, consistent with electroweak symmetry breaking constraints,
are presented as illustrations.Comment: 19 pages. Minor modificaitons are made in the text. This version is
to appear in Physical Review
High-scale validity of a two Higgs doublet scenario: metastability included
We make an attempt to identify regions in a Type II Two-Higgs Doublet Model,
which correspond to a metastable electroweak vacuum with lifetime larger than
the age of the universe. We analyse scenarios which retain perturbative
unitarity up to Grand unification and Planck scales. Each point in the
parameter space is restricted using Data from the Large Hadron Collider (LHC)
as well as flavor and precision electroweak constraints. We find that
substantial regions of the parameter space are thus identified as corresponding
to metastability, which compliment the allowed regions for absolute stability,
for top quark mass at the high as well as low end of its currently allowed
range. Thus, a two-Higgs doublet scenario with the electroweak vacuum, either
stable or metastable, can sail through all the way up to the Planck scale
without facing any contradictions
Some Signals for a Light Neutralino
If a light gaugino sector exists in the supersymmetric standard model then
the mass of lightest neutralino may be of the order of 1 GeV or less. As a
consequence of neutral flavor violation in supersymmetric theories -meson
may decay into a pair of lightest neutralinos in such a case. It is found that
the parameter space for such light neutralinos can be appreciably constrained
by looking for such decays. We also show how a rare B-decays ( channels) can help us in probing a light
neutralino in B-factories in a reasonably model- independent manner. Finally,
we observe that that the decay of a tau-lepton into a muon and a pair of light
neutralinos can cause a violation of weak universality which is larger in
magnitude than that from any source known so far.Comment: LaTex File, 6 Pages, Two Figures (available from authors by request).
Presented at the International Workshops on Particle Theory and
Phenomenology, IITAP, Iowa State University, USA, May 17-26, 199
Scalar three-body decays and signals for new physics
If massive invisible particles are pair-produced in a three-body decay, then
the energy distribution of the other (visible) product is sensitive to the mass
of the invisible pair. We use this fact in the context of a Higgs boson
decaying into (i)a Z-boson and two massive neutrinos of a fourth generation,
and (ii)a Z and two lightest particles in the minimal supersymmetric standard
model. We discuss how the Z-energy spectrum in each case can reflect the values
of the parameters in such models. (3 figures, hard copies available from
authers on request).Comment: 11 pages, latex, MRI-PHY/8/9
- âŠ