265 research outputs found
Three-flavor analysis of long-baseline experiments
We compare the analysis of existing and future neutrino oscillation
long-baseline experiments, where we point out that the analysis of future
experiments actually implies a 12-dimensional parameter space. Within the
three-flavor neutrino oscillation framework, six of these parameters are the
fit parameters, and six are the simulated parameters. This high-dimensional
parameter space requires the condensation of information and the definition of
performance indicators for the purpose needed. As the most sophisticated
example for such an indicator, we choose the precision of the leptonic CP
phase, and discuss some of the complications of its computation and
interpretation.Comment: Talk given at the 6th International Workshop on Neutrino Factories &
Superbeams, July 26-Aug 1, 2004, Osaka, Japan. 3 page
Physics reach of -beams and -factories: the problem of degeneracies
We discuss the physics reach of -Beams and -Factories from a
theoretical perspective, having as a guideline the problem of degeneracies. The
presence of degenerate solutions in the measure of the neutrino oscillation
parameters and is, in fact, the main problem that have
to be addressed in planning future neutrino oscillation experiments. If
degeneracies are not (at least partially) solved, it will be almost impossible
to perform, at any future facility, precise measurements of
and/or . After a pedagogical introduction on why degenerate solutions
arise and how we can get rid of them, we analyze the physics reach of current
-beam and -factory configurations. The physics reach of the
"standard" \BB is severely affected by degeneracies while a better result can
be obtained by higher- setups. At the \NF the combination of Golden and
Silver channels can solve the eightfold degeneracy down to Comment: 5 pages, 6 epsfig; NUFACT'05, 21-26 June 2005, Frascat
CP, T and CPT violation in future long baseline experiments
I give a short overview about the possibilities and problems related to the
measurement of CP violation in long baseline experiments. Special attention is
paid to the issue of degeneracies and a method for their resolution is
quantitatively discussed. The CP violation reach for different experiments is
compared in dependence of and \dm{21}. Furthermore a
short comment about the possible effects of matter induced T violation is made.
Finally the limits on CPT violation obtainable at a neutrino factory are shown.Comment: Talk presented at NUFACT02, London, 1-6 July, 2002. 3 pages, 2
figure
Neutrino Factory Superbeam
We discuss the optimization of a neutrino factory for large \sin^2 2
\theta_{13}, where we assume minimum effort on the accelerator side. This
implies that we use low muon energies for the price of an optimized detection
system. We demonstrate that such a neutrino factory performs excellent if
combined with the electron neutrino appearance channel. Instead of the platinum
channel operated with the muon neutrinos from the muon decays, we propose to
use the initial superbeam from the decaying pions and kaons, which might be
utilized at little extra effort. Since we assume out-of-phase bunches arriving
at the same detector, we do not require electron charge identification. In
addition, we can choose the proton energy such that we obtain a synergistic
spectrum peaking at lower energies. We find that both the superbeam and the
neutrino factory beam should used at the identical baseline to reduce matter
density uncertainties, possibly with the same detector. This effectively makes
the configuration a single experiment, which we call ``neutrino factory
superbeam''. We demonstrate that this experiment outperforms a low-energy
neutrino factory or a wide band beam alone beyond a simple addition of
statistics.Comment: 7 pages, 5 figures, 1 tabl
Physics Reach with a Monochromatic Neutrino Beam from Electron Capture
Neutrino oscillation experiments from different sources have demonstrated
non-vanishing neutrino masses and flavour mixings. The next experiments have to
address the determination of the connecting mixing U(e3) and the existence of
the CP violating phase. Whereas U(e3) measures the strength of the oscillation
probability in appearance experiments, the CP phase acts as a phase-shift in
the interference pattern. Here we propose to separate these two parameters by
energy dependence, using the novel idea of a monochromatic neutrino beam
facility based on the acceleration of ions that decay fast through electron
capture. Fine tuning of the boosted neutrino energy allows precision
measurements able to open a window for the discovery of CP violation, even for
a mixing as small as 1 degree.Comment: 4 pages, 1 figure. Talk given at the International Europhysics
Conference on High Energy Physics, HEP-EPS 2005, Lisbon, Portugal, July
21-27, 200
Perspectives in Neutrino Physics: Monochromatic Neutrino Beams
In the last few years spectacular results have been achieved with the
demonstration of non vanishing neutrino masses and flavour mixing. The ultimate
goal is the understanding of the origin of these properties from new physics.
In this road, the last unknown mixing must be determined. If it is
proved to be non-zero, the possibility is open for Charge Conjugation-Parity
(CP) violation in the lepton sector. This will require precision experiments
with a very intense neutrino source. Here a novel method to create a
monochromatic neutrino beam, an old dream for neutrino physics, is proposed
based on the recent discovery of nuclei that decay fast through electron
capture. Such nuclei will generate a monochromatic directional neutrino beam
when decaying at high energy in a storage ring with long straight sections. We
also show that the capacity of such a facility to discover new physics is
impressive, so that fine tuning of the boosted neutrino energy allows precision
measurements of the oscillation parameters even for a mixing as
small as 1 degree. We can thus open a window to the discovery of CP violation
in neutrino oscillations.Comment: 15 pages, 7 figures. Contribution to the proceedings of GUSTAVOFEST -
Symposium in Honour of Gustavo C. Branco: CP Violation and the Flavour
Puzzle, Lisbon, Portugal, 19-20 July 200
Physics Potential of the SPL Super Beam
Performances of a neutrino beam generated by the CERN SPL proton driver are
computed considering a 440 kton water Cerenkov detector at 130 km from the
target. sensitivity down to and a
sensitivity comparable to a Neutrino Factory, for ,
are within the reach of such a project.Comment: Invited talk at the Nufact02 Workshop, Imperial College of Science,
Technology and Medicine, London, July 200
Summary of Working Group 1: Theory Part
I will summarize theoretical issues in Working Group 1 at Nufact'01. Although
there may not be complete agreement yet on the exact optimum baseline and
the muon energy for measurements of the CP phase at a neutrino factory,
all the works done so far indicate that the optimum set (, ) tends to
be smaller than (3000km, 50GeV) if the uncertainty of the matter effect is
assumed to be larger than 5% or the background fraction is much larger
than .Comment: 9 pages, uses elsart.cls. Summary talk of theoretical part of WG1 at
3rd International Workshop on Neutrino Factory based on Muon Storage Rings
(NuFACT'01), Tsukuba, Japan, 24-30 May 2001 . 1 references added slight
modification adde
Geographical issues and physics applications of "very" long neutrino factory baselines
We discuss several potential applications of ``very'' long neutrino factory
baselines, as well as potential detector locations for these applications.Comment: 2 pages, 2 figures; Talk given at the NuFact 05 workshop, June 21-26,
Frascati, Ital
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