688 research outputs found
Physics potential of the CERN-MEMPHYS neutrino oscillation project
We consider the physics potential of CERN based neutrino oscillation
experiments consisting of a Beta Beam (BB) and a Super Beam (SPL) sending
neutrinos to MEMPHYS, a 440 kt water \v{C}erenkov detector at Frejus, at a
distance of 130 km from CERN. The discovery reach and the
sensitivity to CP violation are investigated, including a detailed discussion
of parameter degeneracies and systematical errors. For SPL sensitivities
similar to the ones of the phase II of the T2K experiment (T2HK) are obtained,
whereas the BB may reach significantly better sensitivities, depending on the
achieved number of total ion decays. The results for the CERN-MEMPHYS
experiments are less affected by systematical uncertainties than T2HK. We point
out that by a combination of data from BB and SPL a measurement with
antineutrinos is not necessary and hence the same physics results can be
obtained within about half of the measurement time compared to one single
experiment. Furthermore, it is shown how including data from atmospheric
neutrinos in the MEMPHYS detector allows to resolve parameter degeneracies and,
in particular, provides sensitivity to the neutrino mass hierarchy and the
octant of .Comment: 32 pages, 17 figures, minor improvements on the text wrt to v2,
version to appear in JHE
Updated fit to three neutrino mixing: status of leptonic CP violation
We present a global analysis of solar, atmospheric, reactor and accelerator
neutrino data in the framework of three-neutrino oscillations based on data
available in summer 2014. We provide the allowed ranges of the six oscillation
parameters and show that their determination is stable with respect to
uncertainties related to reactor neutrino and solar neutrino flux predictions.
We find that the maximal possible value of the Jarlskog invariant in the lepton
sector is () at the () level
and we use leptonic unitarity triangles to illustrate the ability of global
oscillation data to obtain information on CP violation. We discuss "tendencies
and tensions" of the global fit related to the octant of as well
as the CP violating phase . The favored values of
are around while values around are
disfavored at about . We comment on the non-trivial task
to assign a confidence level to this value by performing a Monte
Carlo study of T2K data.Comment: 28 pages, 10 figures, 1 table. Typos corrected. Updated results of
the global fit will be available at http://www.nu-fit.org
Lepton masses, mixings and FCNC in a minimal S_3-invariant extension of the Standard Model
The mass matrices of the charged leptons and neutrinos, previously derived in
a minimal S_3-invariant extension of the Standard Model, were reparametrized in
terms of their eigenvalues. We obtained explicit, analytical expressions for
all entries in the neutrino mixing matrix, V_PMNS, the neutrino mixing angles
and the Majorana phases as functions of the masses of charged leptons and
neutrinos in excellent agreement with the latest experimental values. The
resulting V_PMNS matrix is very close to the tri-bimaximal form of the neutrino
mixing matrix. We also derived explicit analytical expressions for the matrices
of the Yukawa couplings and computed the branching ratios of some selected
flavour changing neutral current processes as functions of the masses of the
charged leptons and the neutral Higgs bosons. We find that the S_3 x Z_2
flavour symmetry and the strong mass hierarchy of the charged leptons strongly
suppress the FCNC processes in the leptonic sector well below the present
experimental upper bounds by many orders of magnitude.Comment: One paragraph added with comparison to tri-bimaximal mixing, two
lines changed in abstract, references added, typographical errors correcte
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