8,949 research outputs found
Sterile Neutrinos: Phenomenology and Theory
A sterile neutrino in addition to the three known neutrinos seems unavoidable
if one wants a simultaneous understanding of the results of the LSND experiment
indicating oscillation together with other evidences for
neutrino oscillations such as those from solar and atmospheric neutrino
deficits. A major theoretical challenge then is to understand why the sterile
neutrino is so light. A simple solution appears to be to assume that it is the
lightest neutrino of a mirror sector of the universe which has identical matter
and gauge content as the standard model. After a brief review of the
phenomenology, a recently constructed realistic grand unified model based on
the gauge group that embeds the mirror universe
idea is presented. Detailed predictions for known and the sterile neutrino
sector are given and their consequences for cosmology are mentioned.Comment: Invited talk presented at the workshop on "New trends in neutrino
physics" held at the Ringberg Castle, Germany, May 24-28, 1998; 10 page
Physics of Neutrino Mass
Recent discoveries in the field of neutrino oscillations have provided a
unique window into physics beyond the standard model. In this lecture, I
summarize how well we understand the various observations, what they tell us
about the nature of new physics and what we are likely to learn as some of the
planned experiments are carried out.Comment: Invited Lecture at the SLAC Summer Institute, August, 2004; 23 pages,
6 figure
Understanding the Standard Model
We explore to what extent the various assumptions behind the standard model
as well as the observed quantization of electric charges of quarks and leptons
can be understood using the Adler-Bell-Jackiw anomalies. The effect of
including a non-zero neutrino mass on these considerations is also discussed.Comment: University of Maryland Report No. UMD-PP-94-116; To be published in
the Robert E. Marshak memorial volume, edited by George Sudarshan. ( plain
Tex; 17 pages
Seesaw Mechanism and Its Implications
The seesaw mechanism for neutrino masses is introduced and some of its
different realizations and applications are discussed. It is pointed out how
they can be used to understand the bi-large mixing patterns among neutrinos in
combination with assumptions about high scale physics such as grand unification
or quasi-degeneracy of neutrino masses.Comment: 14 pages; 2 figures; Invited talk presented at the SEESAW25
conference in Paris, June, 2004; a slightly shorter version will appear in
the proceedings of SEESAW 25. This version contains a more references to
original paper
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