49,398 research outputs found
Determination of the Heat Resistance of Microbial Isolates from EASL
Dry heat resistance of bacterial spores from sterilization and assembly laborator
with leptoquarks and the origin of Yukawa couplings
We construct a model where the Yukawa couplings of the Standard Model (SM)
fermions arise from the breaking of a symmetry and through mixing with a
fourth family of vector-like fermions. By adding a scalar leptoquark, which is
an electroweak triplet and odd under the symmetry, we obtain an
explanation for that is linked to the origin of the Yukawa
couplings. The coupling of SM fermions to the leptoquark is mediated by the
fourth family fermions, and is predicted to be related to CKM entries and mass
ratios of SM fermions.Comment: 17 pages, 2 figures. Version accepted for publication in JHE
An SUSY GUT of flavour in 6d
We propose a 6d model with a SUSY gauge symmetry. After
compactification, it explains the origin of the Family Symmetry with CSD3
vacuum alignment, as well as breaking with doublet-triplet splitting.
The model naturally accounts for all quark and lepton (including neutrino)
masses and mixings, incorporating the highly predictive Littlest Seesaw
structure. It spontaneously breaks CP symmetry, resulting in successful CP
violation in the quark and lepton sectors, while solving the Strong CP problem.
It also explains the Baryon Asymmetry of the Universe (BAU) through
leptogenesis, with the leptogenesis phase directly linked to the Dirac and
Majorana phases.Comment: 23 pages, 6 figures. v3: Version published in JHE
SU(3) family symmetry and neutrino bi-tri-maximal mixing
The observed large mixing angles in the lepton sector may be the first signal
for the presence of a non-Abelian family symmetry. However, to obtain the
significant differences between the mixing of the neutrino and charged fermion
sectors, the vacuum expectation values involved in the breaking of such a
symmetry in the two sectors must be misaligned. We investigate how this can be
achieved in models with an SU(3) family symmetry consistent with an underlying
GUT. We show that such misalignment can be achieved naturally via the see-saw
mechanism. We construct a specific example in which the vacuum (mis)alignment
is guaranteed by additional symmetries. This model generates a fermion mass
structure consistent with all quark and lepton masses and mixing angles.
Neutrino mixing is close to bi-tri-maximal mixing.Comment: References added; typos correcte
Investigating the Apparent Seismic Diffusivity of Near-Receiver Geology at Mount St. Helens Volcano, USA
Acknowledgments: The SAGES VALIDATE forum provided travel money for the discussion of the methodology within De Siena and Benson.Peer reviewedPublisher PD
Representation of probabilistic scientific knowledge
This article is available through the Brunel Open Access Publishing Fund. Copyright © 2013 Soldatova et al; licensee BioMed Central Ltd.The theory of probability is widely used in biomedical research for data analysis and modelling. In previous work the probabilities of the research hypotheses have been recorded as experimental metadata. The ontology HELO is designed to support probabilistic reasoning, and provides semantic descriptors for reporting on research that involves operations with probabilities. HELO explicitly links research statements such as hypotheses, models, laws, conclusions, etc. to the associated probabilities of these statements being true. HELO enables the explicit semantic representation and accurate recording of probabilities in hypotheses, as well as the inference methods used to generate and update those hypotheses. We demonstrate the utility of HELO on three worked examples: changes in the probability of the hypothesis that sirtuins regulate human life span; changes in the probability of hypotheses about gene functions in the S. cerevisiae aromatic amino acid pathway; and the use of active learning in drug design (quantitative structure activity relation learning), where a strategy for the selection of compounds with the highest probability of improving on the best known compound was used. HELO is open source and available at https://github.com/larisa-soldatova/HELO.This work was partially supported by grant BB/F008228/1 from the UK Biotechnology & Biological Sciences Research Council, from the European Commission under the FP7 Collaborative Programme, UNICELLSYS, KU Leuven GOA/08/008 and ERC Starting Grant 240186
Grand Unified Theory of Flavour and Leptogenesis
We propose a Grand Unified Theory of Flavour, based on together with
a non-Abelian discrete group , under which the unified three quark and
lepton 16-plets are unified into a single triplet . The model involves a
further discrete group which controls
the Higgs and flavon symmetry breaking sectors. The CSD2 flavon vacuum
alignment is discussed, along with the GUT breaking potential and the
doublet-triplet splitting, and proton decay is shown to be under control. The
Yukawa matrices are derived in detail, from renormalisable diagrams, and
neutrino masses emerge from the type I seesaw mechanism. A full numerical fit
is performed with 15 input parameters generating 19 presently constrained
observables, taking into account supersymmetry threshold corrections. The model
predicts a normal neutrino mass ordering with a CP oscillation phase of
, an atmospheric angle in the first octant and neutrinoless double
beta decay with meV. We discuss leptogenesis, which
fixes the second right-handed neutrino mass to be
GeV, in the natural range predicted by the model.Comment: 26 pages, 10 figure
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