1,003 research outputs found
A Supersymmetric D4 Model for mu-tau Symmetry
We construct a supersymmeterized version of the model presented by Grimus and
Lavoura (GL) in [1] which predicts theta_{23} maximal and theta_{13}=0 in the
lepton sector. For this purpose, we extend the flavor group, which is D4 x
Z2^{(aux)} in the original model, to D4 x Z5. An additional difference is the
absence of right-handed neutrinos. Despite these changes the model is the same
as the GL model, since theta_{23} maximal and theta_{13}=0 arise through the
same mismatch of D4 subgroups, D2 in the charged lepton and Z2 in the neutrino
sector. In our setup D4 is solely broken by gauge singlets, the flavons. We
show that their vacuum structure, which leads to the prediction of theta_{13}
and theta_{23}, is a natural result of the scalar potential. We find that the
neutrino mass matrix only allows for inverted hierarchy, if we assume a certain
form of spontaneous CP violation. The quantity |m_{ee}|, measured in
neutrinoless double beta decay, is nearly equal to the lightest neutrino mass
m3. The Majorana phases phi1 and phi2 are restricted to a certain range for m3
< 0.06 eV. We discuss the next-to-leading order corrections which give rise to
shifts in the vacuum expectation values of the flavons. These induce deviations
from maximal atmospheric mixing and vanishing theta_{13}. It turns out that
these deviations are smaller for theta_{23} than for theta_{13}.Comment: 19 pages, 4 figure
Quark contact interactions at the LHC
Quark contact interactions are an important signal of new physics. We
introduce a model in which the presence of a symmetry protects these new
interactions from giving large corrections in flavor changing processes at low
energies. This minimal model provides the basic set of operators which must be
considered to contribute to the high-energy processes. To discuss their
experimental signature in jet pairs produced in proton-proton colllisions, we
simplify the number of possible operators down to two. We show (for a
representative integrated luminosity of 200 pb^-1 at \surd s = 7 TeV) how the
presence of two operators significantly modifies the bound on the
characteristic energy scale of the contact interactions which is obtained by
keeping a single operator.Comment: 8 pages, 2 figure
Oedipus, Ninetto, Davide: Sin and Blindness between Morante and Pasolini
The article tries to analyze the dense and complex artistic relations between Pier Paolo Pasolini and Elsa Morante. Starting from the different representations the Oedipus myth in the film Edipo Re by Pier Paolo Pasolini and in the drama La serata a Colono by Elsa Morante, the article analyzes affinities and differences between Morante and Pasolini in the definition of the concept of guilt. The analysis of guilt takes place as a discussion of the presence of the Myth of Oedipus in both authors. In the case of Morante the analysis is focused on the character of Davide in La Storia; in this way it is determined a relation between guilt and blindness
Ultrasound imaging, a stethoscope for body composition assessment
Bone and muscle are two deeply interconnected organs and a strong relationship between them exists in their development and maintenance. The peak of both bone and muscle mass is achieved in early adulthood, followed by a progressive decline after the age of 40. The increase in life expectancy in developed countries resulted in an increase of degenerative diseases affecting the musculoskeletal system. Osteoporosis and sarcopenia represent a major cause of morbidity and mortality in the elderly population and are associated with a significant increase in healthcare costs. Several imaging techniques are currently available for the non-invasive investigation of bone and muscle mass and quality. Conventional radiology, dual energy X-ray absorptiometry (DXA), computed tomography (CT), magnetic resonance imaging (MRI) and ultrasound often play a complementary role in the study of osteoporosis and sarcopenia, depicting different aspects of the same pathology. This paper presents the different imaging modalities currently used for the investigation of bone and muscle mass and quality in osteoporosis and sarcopenia with special emphasis on the clinical applications and limitations of each technique and with the intent to provide interesting insights into recent advances in the field of conventional imaging, novel high-resolution techniques and fracture risk
Spondylocarpotarsal synostosis syndrome: \u201cBat wings\u201d spinal fusions and \u201cladybug\u201d carpal coalitions
No abstract availabl
A simple inert model solves the little hierarchy problem and provides a dark matter candidate
We discuss a minimal extension to the standard model in which two singlet
scalar states that only interacts with the Higgs boson is added. Their masses
and interaction strengths are fixed by the two requirements of canceling the
one-loop quadratic corrections to the Higgs boson mass and providing a viable
dark matter candidate. Direct detection of the lightest of these new states in
nuclear scattering experiments is possible with a cross section within reach of
future experiments.Comment: Finite corrections included. Model modified. Conclusion unchange
Non-Abelian Discrete Flavor Symmetries from T^2/Z_N Orbifolds
In [1] it was shown how the flavor symmetry A4 (or S4) can arise if the three
fermion generations are taken to live on the fixed points of a specific
2-dimensional orbifold. The flavor symmetry is a remnant of the 6-dimensional
Poincare symmetry, after it is broken down to the 4-dimensional Poincare
symmetry through compactification via orbifolding. This raises the question if
there are further non-abelian discrete symmetries that can arise in a similar
setup. To this end, we generalize the discussion by considering all possible
2-dimensional orbifolds and the flavor symmetries that arise from them. The
symmetries we obtain from these orbifolds are, in addition to S4 and A4, the
groups D3, D4 and D6 \simeq D3 x Z2 which are all popular groups for flavored
model building.Comment: 12 pages, 4 figure
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