422 research outputs found
Exotic Solutions to the Solar Neutrino Problem and Some Implications for Low Energy Solar Neutrino Experiments
In this talk, I review, from the phenomenological point of view, solutions to
the solar neutrino problem, which are not provided by the conventional neutrino
oscillation induced by mass and flavor mixing, and show that they can provide a
good fit to the observed data. I also consider some simple implications for low
energy solar neutrino experiments.Comment: Talk presented at International Workshop on Low Energy Solar
Neutrinos (LowNu2), 4-5, December, 2000, Tokyo, Japan, to be published in
Proceedings (World Scientific
CERN to Gran Sasso: An ideal distance for superbeam?
We use the CP trajectory diagram as a tool for pictorial representation of the genuine CP and the matter effects to explore the possibility of an in situ simultaneous measurement of \delta and the sign of \Delta m^2_{13}. We end up with a low-energy conventional superbeam experiment with a megaton-class water Cherenkov detector and baseline length of about 700 km. A picturesque description of the combined ambiguity which may arise in simultaneous determination of \theta_{13} and the above two quantities is given in terms of CP trajectory diagram
Probing supernova physics with neutrino oscillations
We point out that solar neutrino oscillations with large mixing angle as
evidenced in current solar neutrino data have a strong impact on strategies for
diagnosing collapse-driven supernova (SN) through neutrino observations. Such
oscillations induce a significant deformation of the energy spectra of
neutrinos, thereby allowing us to obtain otherwise inaccessible features of SN
neutrino spectra. We demonstrate that one can determine temperatures and
luminosities of non-electron flavor neutrinos by observing bar{nu}_{e} from
galactic SN in massive water Cherenkov detectors by the charged current
reactions on protons.Comment: 6 pages. Typos corrected and references added. Version to be
published in Physics Letters
What can we learn about the lepton CP phase in the next 10 years?
We discuss how the lepton CP phase can be constrained by accelerator and
reactor measurements in an era without dedicated experiments for CP violation
search. To characterize globally the sensitivity to the CP phase \delta_{CP},
we introduce a new measure, the CP exclusion fraction, which quantifies what
fraction of the \delta_{CP} space can be excluded at a given input values of
\theta_{23} and \delta_{CP}. Using the measure we study the CP sensitivity
which may be possessed by the accelerator experiments T2K and NOvA. We show
that, if the mass hierarchy is known, T2K and NOvA alone may exclude,
respectively, about 50%-60% and 40%-50% of the \delta_{CP} space at 90% CL by
10 years running, provided that a considerable fraction of beam time is devoted
to the antineutrino run. The synergy between T2K and NOvA is remarkable,
leading to the determination of the mass hierarchy through CP sensitivity at
the same CL.Comment: Analyses and plots improved, conclusions unchanged, 23 pages, 8
figures, 1 tabl
Constraining the absolute neutrino mass scale and Majorana CP violating phases by future neutrinoless double beta decay experiments
Assuming that neutrinos are Majorana particles, in a three generation
framework, current and future neutrino oscillation experiments can determine
six out of the nine parameters which fully describe the structure of the
neutrino mass matrix. We try to clarify the interplay among the remaining
parameters, the absolute neutrino mass scale and two CP violating Majorana
phases, and how they can be accessed by future neutrinoless double beta
() decay experiments, for the normal as well as for the
inverted order of the neutrino mass spectrum. Assuming the oscillation
parameters to be in the range presently allowed by atmospheric, solar, reactor
and accelerator neutrino experiments, we quantitatively estimate the bounds on
, the lightest neutrino mass, that can be infered if the next generation
decay experiments can probe the effective Majorana mass
() down to
1 meV. In this context we conclude that in the case neutrinos are
Majorana particles: (a) if m_0 \gsim 300 meV, {\em i.e.}, within the range
directly attainable by future laboratory experiments as well as astrophysical
observations, then m_{ee} \gsim 30 meV must be observed;
(b) if meV, results from future decay
experiments combined with stringent bounds on the neutrino oscillation
parameters, specially the solar ones, will place much stronger limits on the
allowed values of than these direct experiments.Comment: 26 pages, 11 encapsulated postscript figures. A new figure and minor
changes are included. To be published in Phys. Rev.
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