The Ernst equation as a motion on a universal Grassmann manifold

We find a linearization of the Ernst equation by means of universal Grassmann manifold (UGM) techniques. All local analytic solutions defined at the origin are obtained by solving an initial value problem for a linear differential equation on a UGM. We give an explicit formula which represents solutions of the Ernst equation. By using this formula, we generate several special solutions.     

Nuclear Spin Alignment and Alignment Correlation Terms in Mass A = 8 System

The pure nuclear spin alignments of ⁸Li and ⁸B were produced from the nuclear spin polarization applying the β-NMR method. The alignment correlation terms in the β-ray angular distribution were observed to test the G parity conservation in the nuclear β decay.     

Quadrupole Moments of Na Isotopes

The electric quadrupole coupling constants eqQ/h of ²⁰Na (I ^π = 2⁺, T _1/2 = 449.7 ms), ²¹Na (I ^π = 3/2, T _1/2 = 22.49 s) and ²⁵Na (I ^π = 5/2, T _1/2 = 59.6 s) in single crystal ZnO and TiO₂ were precisely measured by applying the β-NMR technique. The ratio of the quadrupole moments between ²⁰Na (²⁵Na) and ²¹Na was determined to be 0.728 ± 0.023 (0.011 ± 0.002).     

Instanton moduli on the quaternion Kähler manifold of type ${\mathbf G_2}$ and singular set

We prove the completeness of an instanton moduli space on quaternion-K?hler manifold . A point in the boundary of the moduli represents an ASD bundle with a particular singular set. It is shown that the singular set is a quaternion submanifold of and the Poincaré dual of the homology class represented by is the second Chern class o f the instanton bundle. Received: 4 July 2000 / Published online: 2 December 2002 Current Address: Faculty of Mathematics, Kyushu University, Ropponmatsu, Fukuoka, 810-8560, Japan (e-mail: nagatomo@math.kyushu-u.ac.jp)     

Ultra slow muon microscopy by laser resonant ionization at J-PARC, MUSE

As one of the principal muon beam line at the J-PARC muon facility (MUSE), we are now constructing a Muon beam line (U-Line), which consists of a large acceptance solenoid made of mineral insulation cables (MIC), a superconducting curved transport solenoid and superconducting axial focusing magnets. There, we can extract 2 × 10⁸/s surface muons towards a hot tungsten target. At the U-Line, we are now establishing a new type of muon microscopy; a new technique with use of the intense ultra-slow muon source generated by resonant ionization of thermal Muonium (designated as Mu; consisting of a μ ^?+? and an e^???) atoms generated from the surface of the tungsten target. In this contribution, the latest status of the Ultra Slow Muon Microscopy project, fully funded, is reported.     

In-beam Mössbauer study of 57Mn implanted into a low-temperature xenon

The in-beam Mössbauer spectrum of ⁵⁷Mn implanted into a Xe solid at 14 K was measured. Four singlets were observed in the spectrum, assigned to ⁵⁷Fe^?+? (3d⁷), ⁵⁷Fe^?+? (3d⁶4s¹), ⁵⁷Fe⁰ (3d⁶4s²), and ⁵⁷Fe⁰ (3d⁷4s¹). The assignments were in agreement with calculated electron densities at nuclei reported in the literature. The β-decay of ⁵⁷Mn did not disturb the surrounding Xe lattice, showing a singlet peak, and the excited states were stabilized in the time range of the Mössbauer measurements of ~100 ns. The production mechanism was explained in terms of the reduction of ⁵⁷Mn ^x?+? and ⁵⁷Fe ^y?+? ions by free electrons in the Xe matrix.     

Time-resolved Mössbauer spectra obtained after 57Mn implantation in Si

A new detector system for the coincidence technique between Mössbauer γ-rays and energetic β-rays originating from ⁵⁷Mn has been developed for in-beam Mössbauer spectroscopy using ⁵⁷Mn implantation. This system enables time-resolved Mössbauer measurements of ⁵⁷Fe at various elapsed times after β ^?-decay of ⁵⁷Mn with sufficient quality. We applied this system to the time-dependent measurement of the site distributions of dilute Fe atoms in n-type Si. It was suggested that Fe atoms were already located at substitutional and interstitial positions in Si within a time of about 100 ns after the β ^?-decay of ⁵⁷Mn, and that the occupancy ratio between these positions was hardly dependent on the elapsed time after the β ^?-decay.