Precise Nuclear Quadrupole Moments of 8B and 13B

The electric quadrupole coupling constants eqQ/h of ⁸B (, T _1/2 = 769 ms) and ¹³B (, T _1/2 = 17.4 ms) in single crystal TiO₂ have been precisely measured by the β-NQR technique. The ratios of these Q moments to Q(¹²B) were determined as ∣Q(⁸B)/Q(¹²B)∣ = 4.882(32) and ∣Q(¹³B)/Q(¹²B)∣ = 2.768(24).     

Lowest- Q2 measurement of the γp → Δ reaction: Probing the pionic contribution

To determine nonspherical angular-momentum amplitudes in hadrons at long ranges (low Q²), data were taken for the p(ˉe, e'p)π⁰ reaction in the Δ region at Q ² = 0.060 (GeV/c)² utilizing the magnetic spectrometers of the A1 Collaboration at MAMI. The results for the dominant transition magnetic dipole amplitude and the quadrupole to dipole ratios at W = 1232 MeV are , Re( )%, and Re( )%. These disagree with predictions of constituent quark models but are in reasonable agreement with lattice calculations with nonlinear (chiral) pion mass extrapolations, with chiral effective field theory, and with dynamical models with pion cloud effects. These results confirm the dominance, and general Q² variation, of the pionic contribution at large distances.     

Mössbauer Study of Microstructure and Magnetic Properties (Co,Ni)–Zr Substituted Ba Ferrite Particles

The β-NMR of short-lived β-emitter in a rutile TiO₂ single crystal has been measured as functions of temperature and external magnetic field. Atomic motion induced spin lattice relaxation was observed for two known sites, O substitutional and interstitial sites. The data were analyzed in terms of the thermal atomic jump, which suggests that the motion of defects around the substitutional ¹²N atom for O, and of the interstitial ¹²N atom are attributed to the spin lattice relaxation. The electric field gradients have shown temperature dependence for both sites, which is probably due to the thermal expansion of rutile.     

Transport properties of CsHSO4 investigated by impedance spectroscopy and nuclear magnetic resonance

Transport properties of the superprotonic conductor, CsHSO₄, have been investigated by impedance spectroscopy and nuclear magnetic resonance (NMR). It has been found that both, conductivity (σ) and NMR diffusion (D _NMR) are practically isotropic in the high-conductive (superprotonic) phase (above 414 K). The NMR diffusion coefficient, D _NMR , increases rapidly and discontinuously at the melting point (~490 K). The temperature change of D _NMR in the superprotonic phase is characterized by a smaller activation energy compared to that in the liquid state. The values calculated from the Nernst-Einstein relation practically coincide with D _NMR in the superprotonic phase, i.e., the Haven ratio is close to unity. This indicates that in this phase the proton motion is rather uncorrelated.     

Laplace Sequences of Surfaces in Projective Space and Two-Dimensional Toda Equations

We find that the Laplace sequences of surfaces of period n in projective space P _n–1 have two types, while type II occurs only for even n. The integrability condition of the fundamental equations of these two types have the same form

Loss of collectivity in 79Rb

High-spin states in ⁷⁹Rb were populated in the reaction at E(beam) = 60 MeV. The lifetimes of the excited states of the positive-parity yrast band and of the negative-parity band in ⁷⁹Rb were measured by the Doppler Shift Attenuation Method. The deduced transition quadrupole moments Q_t are found to have a decreasing trend with rotational frequency for both the bands, consistent with those found experimentally in neighbouring nuclei. An erratum to this article is available at .     

NMR Studies on the Internal Structure of High-T c Superconductors and Other Anorganic Compounds

Spatially-resolved NMR is used to probe internal structures in highly correlated superconductors of optimally-doped (T _c = 85 K) and a heavy fermion superconductor CeCoIn₅ (T _c = 2.3 K). The characteristic change of the properties of ²⁰⁵Tl-NMR in the vortex state provides a clear evidence of the antiferromagnetic order in the vortex cores below 20 K in . We also obtain anomalous ¹¹⁵In-NMR spectra of CeCoIn₅, which provides a microscopic evidence for the occurrence of a spatially-modulated superconducting order parameter expected in a Fulde–Ferrel–Larkin–Ovchinnkov (FFLO) state.     

Evaluation ofS,T, U parameters, triple gauge boson vertices and some oblique corrections in extraU(1) superstring inspired model

Explicit evaluation of the following parameters has been carried out in the extraU (1) superstring inspired model: (i) As Mz₂ varies from 555 GeV to 620 GeV and (m _t) CDF = 175.6 ± 5.7 GeV (Table 1): (a) S^New varies from -0.100 ± 0.089 to -0.130 ± 0.090, (b) T^New varies from -0.098 ± 0.097 to -0.129 ± 0.098, (c) U^New varies from -0.229 ± 0.177 to -0.253 ± 0.206, (d) Τ_z varies from 2.487 ± 0.027 to 2.486 ± 0.027, (e) A_LR varies from 0.0125 ± 0.0003 to 0.0126 ± 0.0003, (f) A _FB ^b remains constant at 0.0080 ± 0.0007. Almost identical values are obtained for (m _t)D0 = 169 GeV (see table 2). (ii) Triple gauge boson vertices (TGV) contributions: AsMz ₂ varies from 555 GeV to 620 GeV and (m _t) CDF = 175.6 ±5.7 GeV. (a)√s = 500 GeV, asymptotic case: varies from -0.301 to -0.179; varies from -0.622 to -0.379; varies from +0.0061 to 0.0056; varies from -3.691 to -2.186. varies from +0.270 to +0.118; varies from +0.552 to 0.238; varies from +0.0004 to +0.0002; remains constant at -0.110. (b)√s = 700 GeV, asymptotic case: varies from -0.297 to -0.176; varies from -0.609 to -0.370; varies from -0.0082 to -0.0078; varies from -3.680 to -2.171.√s = 700 GeV, nonasymptotic case: varies from -0.173 to -0.299; varies from-0.343 to -0.591; varies from -0.005 to -0.011; remains constant at -0.110. The pattern of form factors values for√s = 1000, 1200 GeV is almost identical to that of√s= 700 GeV. Further the values of the form factors for (m _t)D0 (=169 GeV) follow identical pattern as that of (m _t) CDF form factors values (see tables 5, 6, 9, 10). We conclude that the values of all the form factors with the exception of these of , are comparable or larger than theS, T values and therefore the TGV contributions are important while deciding the use of extraU (1) model for doing physics beyond standard model.     

A measurement of semileptonic B decaysto narrow orbitally-excited charm mesons

The decay chain is identified in a sample of 3.9 million hadronic Z decays collected with the OPAL detector at LEP. The branching ratio BR is measured to be for the J ^P =1⁺ (D⁰ ₁) state. For decays into the J ^P =2⁺ (D₂ ^*0) state, an upper limit of 1.4 x 10^-3 is placed on the branching ratio at the 95% confidence level.Received: 20 December 2002, Revised: 15 April 2003, Published online: 12 September 2003     

Probing signals of the littlest Higgs model via the WW fusion processes at the high energy e + e- collider

In the framework of the littlest Higgs (LH) model, we consider the processes and , and we calculate the contributions of new particles to the cross sections of these processes in the future high energy e ⁺ e^- collider (ILC) with TeV. We find that, with reasonable values of the free parameters, the deviations of the cross sections for the processes from their SM values might be comparable to the future ILC measurement precision. The contributions of the light Higgs boson H⁰ to the process are significantly large in all of the parameter space preferred by the electroweak precision data, which might be detected in the future ILC experiments. However, the contributions of the new gauge bosons B_H and Z_H to this process are very small.Received: 22 February 2005, Revised: 27 April 2005, Published online: 6 July 2005PACS: 12.60.Cn, 14.70.Pw, 14.80.Cp     

An expansion of Hartree-Fock and correlation energies,relativistic corrections and the dipole matrix element in the powers of of 1/Z

Feynman diagrammatic technique was used for the calculation of Hartree-Fock and correlation energies, relativistic corrections, dipole matrix element. The whole energy of atomic system was defined as a polen-electron Green function. Breit operator was used for the calculation of relativistic corrections. The Feynman diagrammatic technique was developed for 〈H_B>. Analytical expressions for the contributions from diagrams were received. The calculations were carried out for the terms of such configurations as 1s² 2sⁿ¹ 2pⁿ² (2 ≧n₁≧ 0, 6≧ n₂ ≧ 0). Numerical results are presented for the energies of the terms in the form $$E = E_0 Z^2 + \Delta {\rm E}_2 + \frac{1}{Z}\Delta {\rm E}_3 + \frac{{\alpha ^2 }}{4}(E_0^r + \Delta {\rm E}_1^r Z^3 )$$ and for fine structure of the terms in the form $$\begin{gathered} \left\langle {1s^2 2s^{n_1 } 2p^{n_2 } LSJ|H_B |1s^2 2s^{n_1 \prime } 2p^{n_2 \prime } L\prime S\prime J} \right\rangle = \hfill \\ = ( - 1)^{\alpha + S\prime + J} \left\{ {\begin{array}{*{20}c} {L S J} \\ {S\prime L\prime 1} \\ \end{array} } \right\}\frac{{\alpha ^2 }}{4}(Z - A)^3 [E^{(0)} (Z - B) + \varepsilon _{co} ] + \hfill \\ + ( - 1)^{L + S\prime + J} \left\{ {\begin{array}{*{20}c} {L S J} \\ {S\prime L\prime 2} \\ \end{array} } \right\}\frac{{\alpha ^2 }}{4}(Z - A)^3 \varepsilon _{cc} . \hfill \\ \end{gathered} $$ Dipole matrix elements are necessary for calculations of oscillator strengths and transition probabilities. For dipole matrix elements two members of expansion by 1/Z have been obtained. Numerical results were presented in the form P(a,a′) = a/Z(1+τ/Z).     

On the Uniqueness of Weak Weyl Representations of the Canonical Commutation Relation

Let (T, H) be a weak Weyl representation of the canonical commutation relation (CCR) with one degree of freedom. Namely T is a symmetric operator and H is a self-adjoint operator on a complex Hilbert space satisfying the weak Weyl relation: for all (the set of real numbers), e^−itH D(T) ⊂ D(T) (i is the imaginary unit and D(T) denotes the domain of T) and . In the context of quantum theory where H is a Hamiltonian, T is called a strong time operator of H. In this paper we prove the following theorem on uniqueness of weak Weyl representations: Let be separable. Assume that H is bounded below with and , where is the set of complex numbers and, for a linear operator A on a Hilbert space, σ(A) denotes the spectrum of A. Then ( is the closure of T) is unitarily equivalent to a direct sum of the weak Weyl representation on the Hilbert space , where is the multiplication operator by the variable and with . Using this theorem, we construct a Weyl representation of the CCR from the weak Weyl representation . This work is supported by the Grant-in-Aid No.17340032 for Scientific Research from Japan Society for the Promotion of Science (JSPS).     

Local Resolvent Estimates for <Emphasis Type="Italic">N</Emphasis>-body Stark Hamiltonians

For an N-body Stark Hamiltonian , the resolvent estimate holds uniformly in with Re and Im , where , and is a compact interval. This estimate is well known as the limiting absorption principle. In this paper, we report that by introducing the localization in the configuration space, a refined resolvent estimate holds uniformly in with Re and Im . Dedicated to Professor Hideo Tamura on the occasion of his 60th birthday     

Neutrino production of dimuons

Neutrino interactions with two muons in the final state have been studied using the Fermilab narrow band beam. A sample of 18v _μ like sign dimuon events withP _μ>9 GeV/c yields 6.6±4.8 events after backgroud subtraction and a prompt rate of (1.0±0.7)×10^?4 per single muon event. The kinematics of these events are compared with those of the non-prompt sources. A total of 437v _μ and 31 \(\bar v_\mu \) opposite sign dimuon events withP _μ>4.3 GeV/c are used to measure the strange quark content of the nucleon: \(\kappa = {{2s} \mathord{\left/ {\vphantom {{2s} {\left( {\bar u + \bar d} \right) = 0.52_{ - 0.15}^{ + 0.17} \left( {or\eta _s \frac{{2s}}{{u + d}} = 0.075 \pm 0.019} \right) for 100< E_v< 230 GeV\left( {\left\langle {Q^2 } \right\rangle = {{23 GeV^2 } \mathord{\left/ {\vphantom {{23 GeV^2 } {c^2 }}} \right. \kern-0em} {c^2 }}} \right)}}} \right. \kern-0em} {\left( {\bar u + \bar d} \right) = 0.52_{ - 0.15}^{ + 0.17} \left( {or\eta _s \frac{{2s}}{{u + d}} = 0.075 \pm 0.019} \right) for 100< E_v< 230 GeV\left( {\left\langle {Q^2 } \right\rangle = {{23 GeV^2 } \mathord{\left/ {\vphantom {{23 GeV^2 } {c^2 }}} \right. \kern-0em} {c^2 }}} \right)}}\) using a charm semileptonic branching ratio of (10.9±1.4)% extracted from measurements ine ⁺ e ^? collisions and neutrino emulsion data.     

Laser-diode-excited Blue Upconversion in Tm3+/Yb3+-codoped TeO2-Ga2O3-R2O (R=Li, Na, K) Glasses

This paper reports on intense blue upconversion in Tm³⁺/Yb³⁺ codoped TeO₂-Ga₂O₃-R₂O(R=Li, Na, K) glasses upon excitation with commercial available laser diode (LD). Effects of alkali ions on the Raman spectra, thermal stability and spectroscopic properties of the tellurite-gallium glasses have also been investigated. Energy transfer and the involved upconversion mechanisms have been discussed. Intense blue upconversion emission centered at 476 nm along with a weak red emission at 650 nm has been observed upon excitation of 977 nm LD, assigned to the transitions of , and and/or of Tm³⁺, respectively. The blue upconversion intensity has a cubelike dependence on incident pump laser power, indicating a three-photon process. However, a quadratic dependence of the 476 nm upconversion intensity on the incident pump laser power has been observed when samples under excitation of 808 nm LD due to a two-photon absorption process. Enhanced upconversion luminescence have been observed with replacing K⁺ for Na⁺ and Li⁺.     

Analysis of Ωb? (bss) and Ωc0 (css) with QCD sum rules

We calculate the masses and the pole residues of the heavy baryons Ω _c ⁰(css) and Ω _b ⁻(bss) with the QCD sum rules. The numerical values  GeV (or  GeV) and  GeV (or  GeV) are in good agreement with the experimental data.     

Structures of the f 0(980), a 0(980) mesons and the strong coupling constants g_{f_0 K^+ K^-} , g_{a_0 K^+ K^-} with light-cone QCD sum rules

Making the assumption of explicit isospin violation arising from f ₀(980)-a ₀(980) mixing, we take the point of view that the scalar mesons f ₀(980) and a ₀(980) have both strange and non-strange quark-antiquark components and evaluate the strong coupling constants within the framework of the light-cone QCD sum rules approach. The large strong scalar-KK couplings through both the and components , , and will support the hadronic dressing mechanism; furthermore, in spite of the constituent structure differences between the f ₀(980) and a ₀(980) mesons, the strange components have larger strong coupling constants with the K ⁺ K ^- state than the corresponding non-strange ones, and . From the existing controversial values, we cannot reach a general consensus on the strong coupling constants and the mixing angles.Received: 9 January 2004, Revised: 23 July 2004, Published online: 2 September 2004     

Absorption of solar radiation by solar neutrinos

We calculate the absorption probability of photons radiated from the surface of the Sun by a left-handed neutrino with definite mass and a typical momentum for which we choose |p₁| = 0.2 MeV, producing a heavier right-handed antineutrino. Considering the two transitions and we obtain the two oscillation lengths L₁₂ = 4960.8 m, L₂₃ = 198.4 m, the two absorption probabilities P₁₂^abs. = 2.5 x 10^-67, P₂₃^abs. = 1.2 x 10^-58 and the two absorption ranges au, au, using a neutrino mass differences of meV, meV and associated transition dipole moments. We collect all necessary theoretical ingredients, i.e. neutrino mass and mixing scheme, induced electromagnetic transition dipole moments, quadratic charged lepton mass asymmetries and their interdependence.Received: 4 November 2003, Revised: 23 March 2004, Published online: 5 May 2004     

Physics beyond the Standard Model through b → s μ ?+? μ ? transition

A comprehensive study of the impact of new-physics operators with different Lorentz structures on decays involving the b ?? s ?? ^?+? ?? ^? transition is performed. The effects of new vector?Caxial vector (VA), scalar?Cpseudoscalar (SP) and tensor (T) interactions on the differential branching ratios, forward?Cbackward asymmetries (A _FB??s), and direct CP asymmetries of ${\bar B}_{\rm s}^0 \to \mu^+ \mu^-$ , ${\bar B}_{\rm d}^0 \to$ $ X_{\rm s} \mu^+ \mu^-$ , ${\bar B}_{\rm s}^0 \to \mu^+ \mu^- \gamma$ , ${\bar B}_{\rm d}^0 \to {\bar K} \mu^+ \mu^-$ , and ${\bar B}_{\rm d}^0\to {\bar{K}^*} \mu^+ \mu^-$ are examined. In ${\bar B}_{\rm d}^0\to {\bar{K}^*} \mu^+ \mu^-$ , we also explore the longitudinal polarization fraction f _L and the angular asymmetries $A_{\rm T}^{(2)}$ and A _LT, the direct CP asymmetries in them, as well as the triple-product CP asymmetries $A_{\rm T}^{\rm (im)}$ and $A^{\rm (im)}_{\rm LT}$ . While the new VA operators can significantly enhance most of the observables beyond the Standard Model predictions, the SP and T operators can do this only for A _FB in ${\bar B}_{\rm d}^0 \to {\bar K} \mu^+ \mu^-$ .