37 research outputs found
On the Domain of Mixing Angles in Three Flavor Neutrino Oscillations
We clarify the domain needed for the mixing angles in three flavor neutrino
oscillations. By comparing the ranges of the transition probabilities as
functions of the domains of the mixing angles, we show that it is necessary and
sufficient to let all mixing angles be in . This holds
irrespectively of any assumptions on the neutrino mass squared differences.Comment: 4 pages, 5 figure
Three flavor neutrino oscillations in matter
We derive analytic expressions for three flavor neutrino oscillations in the
presence of matter in the plane wave approximation using the Cayley-Hamilton
formalism. Especially, we calculate the time evolution operator in both flavor
and mass bases. Furthermore, we find the transition probabilities, matter mass
squared differences, and matter mixing angles all expressed in terms of the
vacuum mass squared differences, the vacuum mixing angles, and the matter
density. The conditions for resonance in the presence of matter are also
studied in some examples.Comment: 25 pages, 6 figures (PostScript), RevTe
Neutrino oscillations with three flavors in matter: Applications to neutrinos traversing the Earth
Analytic formulas are presented for three flavor neutrino oscillations in
matter in the plane wave approximation. We calculate in particular the time
evolution operator in both mass and flavor bases. We also find the transition
probabilities expressed as functions of the vacuum mass squared differences,
the vacuum mixing angles, and the matter density parameter. The application of
this to neutrino oscillations for both atmospheric and long baseline neutrinos
in a mantle-core-mantle step function model of the Earth's matter density
profile is discussed.Comment: 14 pages, 4 figures (PostScript), Elsevier LaTe
Magnetic moments of the 3/2 resonances and their quark spin structure
We discuss magnetic moments of the baryons based on an earlier model
for the baryon magnetic moments, allowing for flavor symmetry breaking in the
quark magnetic moments as well as a general quark spin structure. From our
earlier analysis of the nucleon-hyperon magnetic moments and the measured
values of the magnetic moments of and we predict the
other magnetic moments and deduce the spin structure of the resonance
particles. We find from experiment that the total spin polarization of the
decuplet baryons, , is considerably smaller than the
non-relativistic quark model value of 3, although the data is still not good
enough to give a precise determination.Comment: 13 pages, REVTeX, 2 figures, minor clarifying change
Octet Baryon Magnetic Moments in the Chiral Quark Model with Configuration Mixing
The Coleman-Glashow sum-rule for magnetic moments is always fulfilled in the
chiral quark model, independently of SU(3) symmetry breaking. This is due to
the structure of the wave functions, coming from the non-relativistic quark
model. Experimentally, the Coleman-Glashow sum-rule is violated by about ten
standard deviations. To overcome this problem, two models of wave functions
with configuration mixing are studied. One of these models violates the
Coleman-Glashow sum-rule to the right degree and also reproduces the octet
baryon magnetic moments rather accurately.Comment: 22 pages, RevTe
Determining Vitamin D Status: A Comparison between Commercially Available Assays
Background: Vitamin D is not only important for bone health but can also affect the development of several non-bone diseases. The definition of vitamin D insufficiency by serum levels of 25-hydroxyvitamin D depends on the clinical outcome but might also be a consequence of analytical methods used for the definition. Although numerous 25-hydroxyvitamin D assays are available, their comparability is uncertain. We therefore aim to investigate the precision, accuracy and clinical consequences of differences in performance between three common commercially available assays. Methodology/Principal Findings: Serum 25-hydroxyvitamin D levels from 204 twins from the Swedish Twin Registry were determined with high-pressure liquid chromatography-atmospheric pressure chemical ionization-mass spectrometry (HPLCAPCI-MS), a radioimmunoassay (RIA) and a chemiluminescent immunoassay (CLIA). High inter-assay disagreement was found. Mean 25-hydroxyvitamin D levels were highest for the HPLC-APCI-MS technique (85 nmol/L, 95% CI 81-89), intermediate for RIA (70 nmol/L, 95% CI 66-74) and lowest with CLIA (60 nmol/L, 95% CI 56-64). Using a 50-nmol/L cut-off, 8% of the subjects were insufficient using HPLC-APCI-MS, 22% with RIA and 43% by CLIA. Because of the heritable component of 25-hydroxyvitamin D status, the accuracy of each method could indirectly be assessed by comparison of within-twin pair correlations. The strongest correlation was found for HPLC-APCI-MS (r = 0.7), intermediate for RIA (r = 0.5) and lowest for CLIA (r = 0.4). Regression analyses between the methods revealed a non-uniform variance (p<0.0001) depending on level of 25-hydroxyvitamin D. Conclusions/Significance: There are substantial inter-assay differences in performance. The most valid method was HPLCAPCI-MS. Calibration between 25-hydroxyvitamin D assays is intricate
Reply to Comment on 'Octet baryon magnetic moments in the chiral quark model with configuration mixing'
We respond to Franklinâs Comment on our article.QC 2010052