327,006 research outputs found
Upper Critical Field Based on the Width of H = B region in a Superconductor
We studied a method of measuring upper critical field (H) of a
superconductor based on the width of H = B region, which
appears in the superconductor that volume defects are many and dominant. Here
we present the basic concept and details of the method. Although H of a
superconductor is fixed according to kind of the superconductor, it is
difficult to measure H experimentally, and the results are different
depending on the experimental conditions. H was calculated from the
theory that pinned fluxes at volume defects are picked out and move into an
inside of the superconductor when their arrangement is the same as that of
H state of the superconductor. H of MgB obtained by the
method was 65.4 Tesla at 0 K. The reason that H obtained by the method
is closer to ultimate H is based on that
F/F is more than 4 when pinned fluxes
at volume defects of 163 nm radius are picked out. The method will help to find
the ultimate H of volume defect-dominating superconductors.Comment: 10 pages, 4figure
A Flexible Parametrization of CKM matrix via Singular-Value-Decomposition Method
We investigate a flexible method in which we can test the unitarity of the
quark flavor mixing matrix step-by-step. Singular-Value-Decomposition (SVD)
techniques are used in analyzing the mixing matrix over a broader parameter
region than the unitarity region. Unitary constraints make us extract CP
violating properties without any specific parametrization when the magnitudes
of at least three mixing matrix elements in three generation quark mixing are
given. This method can also be applied to the analysis of lepton flavor mixing,
in which only a few moduli are presently measured.Comment: 20 pages, 2 figure
Full Numerical Estimation of Neutrino Mixing Parameters from Solar Neutrino Data
We have numerically computed survival probabilities of solar neutrinos
interacting with matter via MSW mechanism in the full three generation
formalism with eV. For , we confirm the two regions found in the two generation
case, (1) with the most likelyhood, small ,
(2) with less likelyhood, large . For
, we find an additional region, (3) with even
less likelyhood, eV and/or . Assuming that the case (1) is valid, we predict
that .Comment: 4 pages, 1 postscript figure, 1 gif figur
Hierarchical Quark Mixing and Bimaximal Lepton Mixing on the Same Footing
We show that not only the hierarchical quark CKM mixing matrix but also the
"bimaximal" lepton flavor mixing matrix can be derived from the same mass
matrix ansatz based on the broken permutation symmetry, by assuming the
hierarchy of neutrino masses to be . We also reproduce the
recently measured angle of unitary triangle, , as well as all the
observed experimental values of of the quark CKM matrix. And
we predict Jarlskog rephasing invariant quantity, , and the upper bound of the same quantity in the lepton sector,
, which may be indeed large enough to generate the
lepton number violation of the universe.Comment: 12 Pages, LaTeX, no figures, corrected hep-ph number and a PACS
numbe
On Lepton Flavor Violation in Tau Decays
We study lepton flavor violation (LFV) in tau decays induced by heavy
Majorana neutrinos within two models: (I) the Standard Model with additional
right-handed heavy Majorana neutrinos, i.e., a typical seesaw-type model; (II)
the Standard Model with left-handed and right-handed neutral singlets, which
are inspired by certain scenarios of SO(10)models and heterotic superstring
models with E_6 symmetry. We calculate various LFV branching ratios and a T-odd
asymmetry. The seesaw Model I predicts very small branching ratios for LFV
processes in most of the parameter space, although in a very restricted
parameter region it can reach maximal branching ratios Br(tau to mu gamma)
approx 10^-9 and Br(tau to 3mu) approx 10^-10. In contrast, Model II may show
branching ratios Br(tau to e gamma) approx 10^-8 and Br(tau to 3e) < 10^-9,
over a sizable region of the parameter space, large enough to be tested by
experiments in the near future.Comment: 19 pages, 5 ps-figures; minor changes, accepted for publication in
Phys. Rev.
Is CDF large anomaly from virtual SUSY threshold effects?
Talk is given at the YITP International Workshop -- `Recent Developments in
QCD and Hadron Physics'. Recent CDF data of the inclusive jet cross section
shows anomalous deviation around large transverse momentum GeV. Is it possible to interpret the anomaly in terms of virtual SUSY
effects. The answer is `NO', because we find that the virtual SUSY loop
interference effects are too small to explain the CDF data.Comment: 6 pages(LaTeX), 2 Postscript figures, uses revtex.sty and axodraw.st
Electroweak Discussion Section Summary
I summarize our work of electroweak discussion section held at the 14th
International Workshop on Weak Interactions and Neutrinos. We discussed about a
few physics topics related to electroweak interactions, including and
physics and weak flavor physics.Comment: 18 pages (1 Figure not included), YUMS 93-25/SNUTP 93-7
A Model-independent Way to Measure
We propose a new model-independent method, to determine the ratio
, which is theoretically described by the phase space factor
and the well-known perturbative QCD correction only. We explore the possible
experimental options: the measurement of inclusive hadronic invariant mass
distributions. We also discuss the relevant experimental backgrounds.Comment: 10 pages, no figures. Talk given at Asian Science Seminar (KOSEF-JSPS
Winter School), Seoul Korea, on February 21 - 28 (1996). Proceedings will be
published by J. Kor. Phys. Soc. (1996
Quantum Mechanics of Neutrino Oscillations
We present a simple but general treatment of neutrino oscillations in the
framework of quantum mechanics using plane waves and intuitive wave packet
principles when necessary. We attempt to clarify some confusing statements that
have recently appeared in the literature.Comment: 13 pages, no figure
Yang-Yang Anomalies and Coexistence Diameters: Simulation of Asymmetric Fluids
A general method for estimating the Yang-Yang ratio, , and
the coexistence-curve diameter of a model fluid via Monte Carlo simulations is
presented on the basis of data for a hard-core square-well (HCSW) fluid and the
restricted primitive model (RPM) electrolyte. The isothermal minima of
are evaluated at in an
box where is the density
fluctuation. The ``complete'' finite-size scaling theory for the
incorporates pressure mixing in the
scaling fields, thereby allowing for a Yang-Yang anomaly.Comment: Submitted for publication in Phys. Rev.
- …