130 research outputs found
Absolute neutrino masses
We discuss the possibility of using experiments timing the propagation of
neutrino beams over large distances to help determine the absolute masses of
the three neutrinos.Comment: 3 pages, 2 figure
Neutrinos with velocities greater than c ?
A possible explanation of the results of the OPERA experiment is presented.
Assuming that the usual value of c should be interpreted as the velocity of
light in dark matter, we call the "true" velocity of light in vacuum, .
Then the OPERA neutrinos can be faster than c but slower than . We also
discuss the relationship between and neutrino masses.Comment: 5 pages, 1 figure, additional references adde
Perturbed S3 neutrinos
We study the effects of the perturbation which violates the permutation
symmetry of three Majorana neutrinos but preserves the well known (23)
interchange symmetry. This is done in the presence of an arbitrary Majorana
phase which serves to insure the degeneracy of the three neutrinos at the
unperturbed level.Comment: 11 pages, 2 figures, with some correction
Are three flavors special?
It has become clearer recently that the regular pattern of three flavor
nonets describing the low spin meson multiplets seems to require some
modification for the case of the spin 0 scalar mesons. One picture which has
had some success, treats the scalars in a chiral Lagrangian framework and
considers them to populate two nonets. These are, in turn, taken to result from
the mixing of two "bare" nonets, one of which is of quark- antiquark type and
the other of two quark- two antiquark type. Here we show that such a mixing is,
before chiral symmetry breaking terms are included, only possible for three
flavors. In other cases, the two types of structure can not have the same
chiral symmetry transformation property. Specifically, our criterion would lead
one to believe that scalar and pseudoscalar states containing charm would not
have "four quark" admixtures.
This work is of potential interest for constructing chiral Lagrangians based
on exact chiral symmetry which is then broken by well known specific terms. It
may also be of interest in studying some kinds of technicolor theories
Chiral Nonet Mixing in pi pi Scattering
Pion pion scattering is studied in a generalized linear sigma model which
contains two scalar nonets (one of quark-antiquark type and the other of
diquark-antidiquark type) and two corresponding pseudoscalar nonets. An
interesting feature concerns the mixing of the four isosinglet scalar mesons
which yield poles in the scattering amplitude. Some realism is introduced by
enforcing exact unitarity via the K-matrix method.
It is shown that a reasonable agreement with experimental data is obtained up
to about 1 GeV. The poles in the unitarized scattering amplitude are studied in
some detail. The lowest pole clearly represents the sigma meson (or f0(600))
with a mass and decay width around 500 MeV. The second pole invites comparison
with the f0(980) which has a mass around 1 GeV and decay width around 100 MeV.
The third and fourth poles, resemble some of the isosinglet state in the
complicated 1-2 GeV region. Some comparison is made to the situation in the
usual SU(3) linear sigma model with a single scalar nonet
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