9 research outputs found
New Linear Codes from Matrix-Product Codes with Polynomial Units
A new construction of codes from old ones is considered, it is an extension
of the matrix-product construction. Several linear codes that improve the
parameters of the known ones are presented
Remaining inconsistencies with solar neutrinos: can spin flavour precession provide a clue?
A few inconsistencies remain after it has been ascertained that LMA is the
dominant solution to the solar neutrino problem: why is the SuperKamiokande
spectrum flat and why is the Chlorine rate prediction over two standard
deviations above the data. There also remains the ananswered and important
question of whether the active neutrino flux is constant or time varying. We
propose a scenario involving spin flavour precession to sterile neutrinos with
three active flavours that predicts a flat SuperK spectrum and a Chlorine rate
prediction more consistent with data. We also argue that running the Borexino
experiment during the next few years may provide a very important clue as to
the possible variability of the solar neutrino flux.Comment: 3 pages, 2 figures, contribution to TAUP 2009 (Rome
Lepton Number Violation in TeV Scale See-Saw Extensions of the Standard Model
The low-energy neutrino physics constraints on the TeV scale type I see-saw
scenarios of neutrino mass generation are revisited. It is shown that lepton
charge (L) violation, associated to the production and decays of heavy Majorana
neutrinos N_{j} having masses in the range of M_j \sim (100 \div 1000) GeV and
present in such scenarios, is hardly to be observed at ongoing and future
particle accelerator experiments, LHC included, because of very strong
constraints on the parameters and couplings responsible for the corresponding
|\Delta L| = 2 processes. If the heavy Majorana neutrinos N_j are observed and
they are associated only with the type I mechanism, they will behave
effectively like pseudo-Dirac fermions. Conversely, the observation of effects
proving the Majorana nature of N_j would imply that these heavy neutrinos have
additional relatively strong couplings to the Standard Model particles or that
light neutrino masses compatible with the observations are generated by a
mechanism other than see-saw (e.g., radiatively at one or two loop level) in
which the heavy Majorana neutrinos N_j are nevertheless involved.Comment: Contribution to the Proceedings of DISCRETE 2010- Symposium on
Prospects in the Physics of Discrete Symmetries, 8 page
Testing the solar LMA region with KamLAND data
We investigate the potential of 3 kiloTon-years(kTy) of KamLAND data to
further constrain the and values compared to those
presently allowed by existing KamLAND and global solar data. We study the
extent, dependence and characteristics of this sensitivity in and around the
two parts of the LMA region that are currently allowed. Our analysis with 3 kTy
simulated spectra shows that KamLAND spectrum data by itself can constrain
with high precision. Combining the spectrum with global solar data
further tightens the constraints on allowed values of and
. We also study the effects of future neutral current data with a
total error of 7% from the Sudbury Neutrino Observatory. We find that these
future measurements offer the potential of considerable precision in
determining the oscillation parameters (specially the mass parameter).Comment: 16 pages, to appear in J Phys.