158 research outputs found
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
Optimal -beam at the CERN-SPS
A -beam with maximum (for \helio ions) or
(for \neon) could be achieved at the CERN-SPS. We study the sensitivity to
and of such a beam as function of , optimizing
with the baseline constrained to CERN-Frejus (130 km), and also with
simultaneous variation of the baseline. These results are compared to the {\it
standard} scenario previously considered, with lower , and also
with a higher option that requires a more powerful
accelerator. Although higher is better, loss of sensitivity to and is most pronounced for below 100.Comment: 22 page
Untangling CP Violation and the Mass Hierarchy in Long Baseline Experiments
In the overlap region, for the normal and inverted hierarchies, of the
neutrino-antineutrino bi-probability space for appearance,
we derive a simple identity between the solutions in the (, ) plane for the different hierarchies. The
parameter sets the scale of the
appearance probabilities at the atmospheric eV whereas controls the amount of CP
violation in the lepton sector. The identity between the solutions is that the
difference in the values of for the two hierarchies equals twice
the value of divided by the {\it critical} value
of . We apply this identity to the two proposed
long baseline experiments, T2K and NOA, and we show how it can be used to
provide a simple understanding of when and why fake solutions are excluded when
two or more experiments are combined. The identity demonstrates the true
complimentarity of T2K and NOA.Comment: 15 pages, Latex, 4 postscript figures. Submitted to New Journal of
Physics, ``Focus on Neutrino Physics'' issu
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 [Ue3] 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 [Ue3] mixing as small as 1 degree. We can
thus open a window to the discovery of CP violation in neutrino oscillations
Physics Reach of Electron-Capture Neutrino Beams
To complete the picture of neutrino oscillations two fundamental parameters
need to be measured, theta13 and delta. The next generation of long baseline
neutrino oscillation experiments -superbeams, betabeams and neutrino factories-
indeed take aim at measuring them. Here we explore the physics reach of a new
candidate: an electron-capture neutrino beam. Emphasis is made on its
feasibility thanks to the recent discovery of nuclei that decay fast through
electron capture, and on the interplay with a betabeam (its closest relative).Comment: 5 pages, 3 png figures. Talk given at the 7th International Workshop
on Neutrino Factories and Superbeams (NuFact 05), Frascati, Italy, June 200
Neutrino Factories and the "Magic" Baseline
We show that for a neutrino factory baseline of a
``clean'' measurement of becomes possible, which is
almost unaffected by parameter degeneracies. We call this baseline "magic"
baseline, because its length only depends on the matter density profile. For a
complete analysis, we demonstrate that the combination of the magic baseline
with a baseline of 3000 km is the ideal solution to perform equally well for
the , sign of , and CP violation
sensitivities. Especially, this combination can very successfully resolve
parameter degeneracies even below .Comment: Minor changes, final version to appear in PRD, 4 pages, 3 figures,
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