1,598 research outputs found
Extension of the Buchalla-Safir bound
I provide a simple derivation of the Buchalla-Safir bound on gamma. I
generalize it to the case where an upper bound on the phase of the penguin
pollution is assumed. I apply the Buchalla-Safir bound, and its generalization,
to the recent Belle data on CP violation in B --> pi+ pi-.Comment: 9 pages, 1 figur
Jarlskog-like invariants for theories with scalars and fermions
Within the framework of theories where both scalars and fermions are present,
we develop a systematic prescription for the construction of CP-violating
quantities that are invariant under basis transformations of those matter
fields. In theories with Spontaneous Symmetry Breaking, the analysis involves
the vevs' transformation properties under a scalar basis change, with a
considerable simplification of the study of CP violation in the scalar sector.
These techniques are then applied in detail to the two Higgs-doublet model with
quarks. It is shown that there are new invariants involving scalar-fermion
interactions, besides those already derived in previous analyses for the
fermion-gauge and scalar-gauge sectors.Comment: 12 pages, Latex, no figure
Measure of the size of CP violation in extended models
In this letter we introduce a possible measure of the size of CP violation in
the Standard Model and its extensions, based on quantities invariant under the
change of weak quark basis. We also introduce a measure of the ``average size''
of CP violation in a model, which can be used to compare the size of CP
violation in models involving extra sequential or vector-like quarks, or
left-right symmetry.Comment: LaTeX, 7 pages, no figure
Lepton-Flavour Violation in Ordinary and Supersymmetric Grand Unified Theories
By an explicit calculation we show that in ordinary SU(5) logarithmic
divergence in the amplitude of cancels among diagrams and
remaining finite part is suppressed by at least . In SUSY SU(5),
when the effect of flavour changing wave function renormalization is taken into
account such logarithmic correction disappears, provided a condition is met
among SUSY breaking masses. In SUGRA-inspired SUSY GUT the remaining
logarithmic effect is argued not to be taken as a prediction of the theory.Comment: 8 pages, LaTeX209 file, using axodraw.st
CP--Violating Invariants in Supersymmetry
I study the weak basis CP-violating invariants in supersymmetric models, in
particular those which cannot be expressed in terms of the Jarlskog--type
invariants, and find basis--independent conditions for CP conservation. With an
example of the K-anti-K mixing, I clarify what are the combinations of
supersymmetric parameters which are constrained by experiment.Comment: matches the PRD versio
PineappleDB: An online pineapple bioinformatics resource
BACKGROUND: A world first pineapple EST sequencing program has been undertaken to investigate genes expressed during non-climacteric fruit ripening and the nematode-plant interaction during root infection. Very little is known of how non-climacteric fruit ripening is controlled or of the molecular basis of the nematode-plant interaction. PineappleDB was developed to provide the research community with access to a curated bioinformatics resource housing the fruit, root and nematode infected gall expressed sequences. DESCRIPTION: PineappleDB is an online, curated database providing integrated access to annotated expressed sequence tag (EST) data for cDNA clones isolated from pineapple fruit, root, and nematode infected root gall vascular cylinder tissues. The database currently houses over 5600 EST sequences, 3383 contig consensus sequences, and associated bioinformatic data including splice variants, Arabidopsis homologues, both MIPS based and Gene Ontology functional classifications, and clone distributions. The online resource can be searched by text or by BLAST sequence homology. The data outputs provide comprehensive sequence, bioinformatic and functional classification information. CONCLUSION: The online pineapple bioinformatic resource provides the research community with access to pineapple fruit and root/gall sequence and bioinformatic data in a user-friendly format. The search tools enable efficient data mining and present a wide spectrum of bioinformatic and functional classification information. PineappleDB will be of broad appeal to researchers investigating pineapple genetics, non-climacteric fruit ripening, root-knot nematode infection, crassulacean acid metabolism and alternative RNA splicing in plants
Supernova Neutrino Oscillations
Observing a high-statistics neutrino signal from a galactic supernova (SN)
would allow one to test the standard delayed explosion scenario and may allow
one to distinguish between the normal and inverted neutrino mass ordering due
to the effects of flavor oscillations in the SN envelope. One may even observe
a signature of SN shock-wave propagation in the detailed time-evolution of the
neutrino spectra. A clear identification of flavor oscillation effects in a
water Cherenkov detector probably requires a megatonne-class experiment.Comment: Proc. 129 Nobel Symposium "Neutrino Physics", 19-24 Aug 2004, Swede
Relation between CKM and MNS Matrices Induced by Bi-Maximal Rotations in the Seesaw Mechanism
It is found that the seesaw mechanism not only explains the smallness of
neutrino masses but also accounts for the large mixing angles simultaneously,
even if the unification of the neutrino Dirac mass matrix with that of up-type
quark sector is realized. In this mechanism, we show that the mixing matrix of
the Dirac-type mass matrix gets extra rotations from the diagonalization of
Majorana mass matrix. Assuming that the mixing angles to diagonalize the
Majorana mass matrix are extremely small, we find that the large mixing angles
of leptonic sector found in atmospheric and long baseline reactor neutrino
oscillation experiments can be explained by these extra rotations. We also find
that provided the mixing angle around y-axis to diagonalize the Majorana mass
matrix vanishes, we can derive the information about the absolute values of
neutrino masses and Majorana mass responsible for the neutrinoless double beta
decay experiment through the data set of neutrino experiments. In the
simplified case that there is no CP phase, we find that the neutrino masses are
decided as and that there are no solution which
satisfy (inverted mass spectrum). Then, including all CP phases,
we reanalyze the absolute values of neutrino masses and Majorana mass
responsible for the neutrinoless double beta decay experiment.Comment: 19 pages, 7 figures, revtex4, to appear in J.PHYS.SOC.JA
Evidence for the formation of two phases during the growth of SrTiO3 on silicon
International audienceEpitaxial SrTiO3 (STO)/Si templates open a unique opportunity for the integration of ferroelectric oxides, such as BaTiO3 on silicon and for the realization of new devices exploiting ferroelectricity. STO itself has been shown as ferroelectric at room temperature when deposited in thin layers on Si, while bulk STO is tetragonal and, thus, ferroelectric below 105 K. Here, we demonstrate the coexistence, at room temperature, of strained cubic and tetragonal phases in thin STO/Si layers. The tetragonal STO phase presents a pronounced tetragonality for thicknesses up to 24 ML. Above this thickness, the strained cubic STO phase starts relaxing while the tetragonal STO phase progressively transits to cubic STO. The origin of the simultaneous formation of these two phases is analyzed and is attributed to oxygen segregation at the early stages of the growth
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