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

Out-of-plane magnetization reversal processes of (Ga,Mn)As with two different hole concentrations

We study magnetization reversal processes of in-plane magnetized (Ga,Mn)As epilayers with different hole concentrations in out-of-plane magnetic fields using magnetotransport measurements. A clear difference in the magnetization process is found in two separate samples with hole concentrations of 10^20 cm^-3 and 10^21 cm^-3 as the magnetization rotates from the out-of-plane saturation to the in-plane remanence. Magnetization switching process from the in-plane remanence to the out-of-plane direction, on the other hand, shows no hole concentration dependence, where the switching process occurs via domain wall propagation. We show that the balance of cubic magnetocrystalline anisotropy and uniaxial [110] anisotropy gives an understanding of the difference in the out-of-plane magnetization processes of (Ga,Mn)As epilayers.Comment: 6 pages, 4 figures, to appear in J. Appl. Phy

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

Production cross sections of gamma-rays, electrons, and positrons in p-p collisions

Because the production cross sections of gamma-rays, electrons, and positrons made in p-p collisions, $\sigma_{pp\rightarrow \gamma}$ and $\sigma_{pp\rightarrow {e}^\pm}$, respectively, are kinematically equivalent with respect to the parent pion-production cross section $\sigma_{pp\rightarrow \pi}$, we obtain $\sigma_{pp\rightarrow {e}^\pm}$ directly from the machine data on $\sigma_{pp\rightarrow \gamma}$. In Sato et al. (2012), we give explicitly $\sigma_{pp\rightarrow \gamma}$, reproducing quite well the accelerator data with LHC, namely $\sigma_{pp\rightarrow {e}^\pm}$ is applicable enough over the wide energy range from GeV to 20\,PeV for projectile proton energy. We dicuss in detail the relation between the cross sections, and present explicitly $\sigma_{pp\rightarrow {e}^\pm}$ that are valid into the PeV electron energy.Comment: 27 pages, 2 tables, 4 figures. Version after major revision. Accepted for publication in Astroparticle Physics; paper can be also downloaded from http://www.phys.aoyama.ac.jp/~ryo/papers/pp-collision2_ApP.pd

Helium Nuclei in Quenched Lattice QCD

We present results for the binding energies for He and ^3He nuclei calculated in quenched lattice QCD at the lattice spacing of a = 0.128 fm with a heavy quark mass corresponding to m_pi = 0.8 GeV. Enormous computational cost for the nucleus correlation functions is reduced by avoiding redundancy of equivalent contractions stemming from permutation symmetry of protons or neutrons in the nucleus and various other symmetries. To distinguish a bound state from an attractive scattering state, we investigate the volume dependence of the energy difference between the nucleus and the free multi-nucleon states 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 to the conclusion that the measured ground states are bounded. It is also encouraging that the measured binding energies and the experimental ones show the same order of magnitude.Comment: 4 pages, 3 figure

BPS Graphs: From Spectral Networks to BPS Quivers

We define "BPS graphs" on punctured Riemann surfaces associated with $A_{N-1}$ theories of class $\mathcal{S}$. 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 $N$-triangulations and generalize them in several ways.Comment: 48 pages, 44 figure

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