10,743 research outputs found
How do Neutrinos Propagate ? - Wave-Packet Treatment of Neutrino Oscillation
The wave-packet treatment of neutrino oscillation developed previously is
extended to the case in which momentum distribution functions are taken to be a
Gaussian form with both central values and dispersions depending on the mass
eigenstates of the neutrinos. It is shown among other things that the velocity
of the neutrino wave packets does not in general agree with what one would
expect classically and that relativistic neutrinos emitted from pions
nevertheless do follow, to a good approximation, the classical trajectory.Comment: 13 page. No figure. Typeset using PTPTeX.st
Mixed magnetic phases in (Ga,Mn)As epilayers
Two different ferromagnetic-paramagnetic transitions are detected in
(Ga,Mn)As/GaAs(001) epilayers from ac susceptibility measurements: transition
at a higher temperature results from (Ga,Mn)As cluster phases with [110]
uniaxial anisotropy and that at a lower temperature is associated with a
ferromagnetic (Ga,Mn)As matrix with cubic anisotropy. A change in the
magnetic easy axis from [100] to [110] with increasing temperature can be
explained by the reduced contribution of cubic anisotropy to the magnetic
properties above the transition temperature of the (Ga,Mn)As matrix
Technique for manufacturing nickel electrodes
A method of manufacturing nickel electrodes distinctive for its use of a composite material for the electrode made up of nickel compound, electrode material, cobalt in metal form or cobalt in compound form is investigated. The composite is over-discharged (same as reverse charging) in an alkaline solution. After dealkalization, synthetic resin adhesive is added and the electrode is formed. Selection of the cobalt compound is made from a group consisting of cobalt oxide, cobalt hydroxide, cobalt carbonate and cobalt sulfate. The method upgrades plate characteristics by using an active material in a non-sintered type nickel electrode, which is activated by electro-chemical effect
Two-Nucleon Bound States in Quenched Lattice QCD
We address the issue of bound state in the two-nucleon system in lattice QCD.
Our study is made in the quenched approximation at the lattice spacing of a =
0.128 fm with a heavy quark mass corresponding to m_pi = 0.8 GeV. To
distinguish a bound state from an attractive scattering state, we investigate
the volume dependence of the energy difference between the ground state and the
free two-nucleon state by changing the spatial extent of the lattice from 3.1
fm to 12.3 fm. A finite energy difference left in the infinite spatial volume
limit leads us to the conclusion that the measured ground states for not only
spin triplet but also singlet channels are bounded. Furthermore the existence
of the bound state is confirmed by investigating the properties of the energy
for the first excited state obtained by 2x2 diagonalization method. The
scattering lengths for both channels are evaluated by applying the finite
volume formula derived by Luscher to the energy of the first excited states.Comment: 34 pages, 28 figure
BPS Graphs: From Spectral Networks to BPS Quivers
We define "BPS graphs" on punctured Riemann surfaces associated with
theories of class . BPS graphs provide a bridge between
two powerful frameworks for studying the spectrum of BPS states: spectral
networks and BPS quivers. They arise from degenerate spectral networks at
maximal intersections of walls of marginal stability on the Coulomb branch.
While the BPS spectrum is ill-defined at such intersections, a BPS graph
captures a useful basis of elementary BPS states. The topology of a BPS graph
encodes a BPS quiver, even for higher-rank theories and for theories with
certain partial punctures. BPS graphs lead to a geometric realization of the
combinatorics of Fock-Goncharov -triangulations and generalize them in
several ways.Comment: 48 pages, 44 figure
Recombining Plasma & Gamma-ray Emission in the Mixed-morphology Supernova Remnant 3C 400.2
3C 400.2 belongs to the mixed morphology supernova remnant class, showing
center-filled X-ray and shell-like radio morphology. We present a study of 3C
400.2 with archival Suzaku and Fermi-LAT observations. We find recombining
plasma (RP) in the Suzaku spectra of north-east and south-east regions. The
spectra of these regions are well described by two-component thermal plasma
models: The hard component is in RP, while the soft component is in collisional
ionization equilibrium (CIE) conditions. The RP has enhanced abundances
indicating that the X-ray emission has an ejecta origin, while the CIE has
solar abundances associated with the interstellar material. The X-ray spectra
of north-west and south-west regions are best fitted by a two-component thermal
plasma model: an ionizing and a CIE plasma. We have detected GeV gamma-ray
emission from 3C 400.2 at the level of 5 assuming a point-like
source model with a power-law (PL) type spectrum. We have also detected a new
GeV source at the level of 13 assuming a Gaussian extension model
with a PL type spectrum in the neighborhood of the SNR. We report the analysis
results of 3C 400.2 and the new extended gamma-ray source and discuss the
nature of gamma-ray emission of 3C 400.2 in the context of existing NANTEN CO
data, DRAO HI data, and the Suzaku X-ray analysis results.Comment: Accepted to be published in the Astrophysical Journa
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