136 research outputs found
Corrections to the fluxes of a Neutrino Factory
In view of their physics goals, future neutrino factories from muon decay aim
at an overall flux precision of or better. We analytically study
the QED radiative corrections to the neutrino differential distributions from
muon decay. Kinematic uncertainties due to the divergence of the muon beam are
considered as well. The resulting corrections to the neutrino flux turn out to
be of order , safely below the required precision.Comment: 22 pages, 8 figures. Some references changed. Final version accepted
for publication in EPJ
Renormalization of Lepton Mixing for Majorana Neutrinos
We discuss the one-loop electroweak renormalization of the leptonic mixing
matrix in the case of Majorana neutrinos, and establish its relationship with
the renormalization group evolution of the dimension five operator responsible
for the light Majorana neutrino masses. We compare our results in the effective
theory with those in the full seesaw theory.Comment: 28 pages. With axodra
Leptogenesis and symmetry
If an exact symmetry is the explanation of the
maximal atmospheric neutrino mixing angle, it has interesting implications for
origin of matter via leptogenesis in models where small neutrino masses arise
via the seesaw mechanism. For seesaw models with two right handed neutrinos
, lepton asymmetry vanishes in the exact symmetric limit, even though there are nonvanishing Majorana phases in
the neutrino mixing matrix. On the other hand, for three right handed neutrino
models, lepton asymmetry nonzero and is given directly by the solar mass
difference square. We also find an upper bound on the lightest neutrino mass.Comment: 5 pages; latex; no figures; some typos correcte
Unveiling Neutrino Mixing and Leptonic CP Violation
We review the present understanding of neutrino masses and mixings,
discussing what are the unknowns in the three family oscillation scenario.
Despite the anticipated success coming from the planned long baseline neutrino
experiments in unraveling the leptonic mixing sector, there are two important
unknowns which may remain obscure: the mixing angle and the
CP-phase . The measurement of these two parameters has led us to
consider the combination of superbeams and neutrino factories as the key to
unveil the neutrino oscillation picture.Comment: Invited brief review, 18 pages, 6 figure
Cardiovascular magnetic resonance (CMR) and positron emission tomography (PET) imaging in the diagnosis and follow-up of patients with acute myocarditis and chronic inflammatory cardiomyopathy : A review paper with practical recommendations on behalf of the European Society of Cardiovascular Radiology (ESCR).
Advanced cardiac imaging techniques such as cardiovascular magnetic resonance (CMR) and positron emission tomography (PET) are widely used in clinical practice in patients with acute myocarditis and chronic inflammatory cardiomyopathies (I-CMP). We aimed to provide a review article with practical recommendations from the European Society of Cardiovascular Radiology (ESCR), in order to guide physicians in the use and interpretation of CMR and PET in clinical practice both for acute myocarditis and follow-up in chronic forms of I-CMP
Phenomenology of symmetry breaking from extra dimensions
Motivated by the electroweak hierarchy problem, we consider theories with two
extra dimensions in which the four-dimensional scalar fields are components of
gauge boson in full space. We explore the Nielsen-Olesen instability for SU(N)
on a torus, in the presence of a magnetic background. A field theory approach
is developed, computing explicitly the minimum of the complete effective
potential, including tri-linear and quartic couplings and determining the
symmetries of the stable vacua. We also develop appropriate gauge-fixing terms
when both Kaluza-Klein and Landau levels are present and interacting,
discussing the interplay between the possible six and four dimensional choices.
The equivalence between coordinate dependent and constant Scherk-Schwarz
boundary conditions -associated to either continuous or discrete Wilson lines-
is analyzed.Comment: 39 pages and 8 eps figures. Few changes in section
Non-unitary Leptonic Mixing and Leptogenesis
We investigate the relation between non-unitarity of the leptonic mixing
matrix and leptogenesis. We discuss how all parameters of the canonical type-I
seesaw mechanism can, in principle, be reconstructed from the neutrino mass
matrix and the deviation of the effective low-energy leptonic mixing matrix
from unitary. When the mass M' of the lightest right-handed neutrino is much
lighter than the masses of the others, we show that its decay asymmetries
within flavour-dependent leptogenesis can be expressed in terms of two
contributions, one depending on the unique dimension five (d=5) operator
generating neutrino masses and one depending on the dimension six (d=6)
operator associated with non-unitarity. In low-energy seesaw scenarios where
small lepton number violation explains the smallness of neutrino masses, the
lepton number conserving d=6 operator contribution generically dominates over
the d=5 operator contribution which results in a strong enhancement of the
flavour-dependent decay asymmetries without any resonance effects. To calculate
the produced final baryon asymmetry, the flavour equilibration effects directly
related to non-unitarity have to be taken into account. In a simple realization
of this non-unitarity driven leptogenesis, the lower bound on M' is found to be
about 10^8 GeV at the onset of the strong washout regime, more than one order
of magnitude below the bound in "standard" thermal leptogenesis.Comment: 19 pages, REVTeX4, 2 eps and 2 axodraw figure
New physics searches at near detectors of neutrino oscillation experiments
We systematically investigate the prospects of testing new physics with tau
sensitive near detectors at neutrino oscillation facilities. For neutrino beams
from pion decay, from the decay of radiative ions, as well as from the decays
of muons in a storage ring at a neutrino factory, we discuss which effective
operators can lead to new physics effects. Furthermore, we discuss the present
bounds on such operators set by other experimental data currently available.
For operators with two leptons and two quarks we present the first complete
analysis including all relevant operators simultaneously and performing a
Markov Chain Monte Carlo fit to the data. We find that these effects can induce
tau neutrino appearance probabilities as large as O(10^{-4}), which are within
reach of forthcoming experiments. We highlight to which kind of new physics a
tau sensitive near detector would be most sensitive.Comment: 20 pages, 2 figures, REVTeX
- …