Revised value of the eighth-order QED contribution to the anomalous magnetic moment of the electron
We have carried out a new evaluation of the eighth-order contribution to the electron g-2 using FORTRAN codes generated by an automatic code generator gencodeN. Comparison of the new result with the old one has revealed an inconsistency in the treatment of the infrared divergences in the latter. With this error corrected we now have two independent determinations of the eighth-order term. This leads to the revised value 1 159 652 182.79(7.71)x10{sup -12} of the electron g-2, where the uncertainty comes mostly from that of the best non-QED value of the fine structure constant {alpha}. The new value of {alpha} derived from the revised theory and the latest experiment is  [0.37 ppb], which is about 4.7 ppb smaller than the previous .

title: VIOLATION OF THE POMERANCHUK THEOREM AND ZEROS OF THE SCATTERING AMPLITUDES.

title: Polarization of Electrons in Muon Decay with General Parity-Nonconserving Interactions
abstract: The polarization of electrons in muon decay is studied in the case of the four-component neutrino theory with general parity-nonconserving interactions. The spectrum for each of the two states of longitudinal polarization is described by a set of three parameters of which only two are independent By observing the electron polarization in arbitrary directions, one can determine ten parameters of which six are related to the two longitudinal polarizations and the rest to the transverse part. It is seen that the prediction of the two-component neutrino theory about the electron polarization in muon decay is quite specific and can be distinguished from that of the general case, if the latter involves the interactionB of the S, T, P types in charge-retention order. However, from the study of the polarization of electrons, it is impossible to distinguish the two-component theory from the four-component theory which involves only the vectortype interactions. It is noticed that the TCP theorem determines a detailed correspondence between the polarization provides us with an opportunity to determine experimentally whether weak interactions actually obey the TCP theorem or not.

title: Automated calculation scheme for alpha**n contributions of QED to lepton g-2: Generating renormalized amplitudes for diagrams without lepton loops
abstract: Among 12 672 Feynman diagrams contributing to the electron anomalous magnetic moment at the tenth order, 6354 are the diagrams having no lepton loops, i.e., those of quenched type. Because the renormalization structure of these diagrams is very complicated, some automation scheme is inevitable to calculate them. We developed an algorithm to write down FORTRAN programs for numerical evaluation of these diagrams, where the necessary counterterms to subtract out ultraviolet subdivergence are generated according to Zimmermann's forest formula. Thus far we have evaluated crudely integrals of 2232 tenth-order vertex diagrams which require vertex renormalization only. Remaining 4122 diagrams, which have ultraviolet-divergent self-energy subdiagrams and infrared-divergent subdiagrams, are being evaluated by giving small mass λ to photons to control the infrared problem.

title: Eighth-order magnetic moment of the electron. III. Sixth-order vertices containing a second-order vacuum polarization subdiagram
abstract: We have calculated the contribution to the eighth-order anomalous magnetic moment of the electron arising from 150 Feynman diagrams, each generated by inserting a second-order vacuum polarization loop in the photon lines of sixth-order vertices of the three-photon-exchange type. Our result is 1.419(16)(..cap alpha../..pi..)/sup 4/. The theoretical error represents the estimated accuracy (90% confidence limit) of the required numerical integrations.

title: Complete tenth-order QED contribution to the muon g-2.
abstract: We report the result of our calculation of the complete tenth-order QED terms of the muon g-2. Our result is a(μ)((10))=753.29 (1.04) in units of (α/π)(5), which is about 4.5 s.d. larger than the leading-logarithmic estimate 663(20). We also improve the precision of the eighth-order QED term of a(μ), obtaining a(μ)((8))=130.8794 (63) in units of (α/π)(4). The new QED contribution is a(μ)(QED)=116,584,718,951 (80)×10(-14), which does not resolve the existing discrepancy between the standard-model prediction and measurement of a(μ).

title: S11(1535) Resonance in Nuclear Medium Observed with the (gamma, eta) Reactions

title: K0 photoproduction on 12C in the threshold region
abstract: The γ n → K 0 Λ process plays an important role in the study of strangeness production by the electromagnetic interaction. We have investigated the quasi-free production reaction on a 12 C target in the threshold region ( E γ = 0.8 – 1.1 GeV ) at the Laboratory of Nuclear Science, Tohoku University. Preliminary results are presented.

title: Photoproduction of neutral kaons on C in the threshold region
abstract: The measurement of neutral kaon photoproduction in the threshold region is in progress at Laboratory of Nuclear Science, Tohoku University. One of the purpose of the experiment is to study electromagnetic strangeness production mechanism, which is necessary for hypernuclear spectroscopy by electromagnetic probes. We have observed K 0 's produced on a carbon target in a commissioning run. Data taking will start in 2003.

title: Photoproduction of η-mesons off C and Cu nuclei for photon energies below 1.1 GeV
abstract: The η -meson photoproduction cross sections have been measured on C and Cu targets for the photon energies between 600 and 1100 MeV to investigate the behavior of the S 11 ( 1535 ) resonance in a nucleus. The excitation functions of the cross section as well as the angular and momentum distributions of η -mesons are in quantitative agreement with the Quantum Molecular Dynamics (QMD) model calculations in which the η -meson emission processes other than the S 11 ( 1535 ) resonance are also incorporated. It is shown that the η production in the γ N → π η N reaction and the D 15 ( 1675 ) resonance formation in the γ n → η n reaction play an important role for E γ > 900 MeV .

title: Narrow resonance at E(gamma) = 1020-MeV in the d (gamma, eta) p n reaction
abstract: Differential and total cross sections of the D(γ, η)pn reaction have been measured for photon energies between 600 and 1150 MeV. The data provide the information of the γn → ηn reaction above Eγ ≥ 800 MeV. The total cross section shows a narrow resonance structure peaked at Eγ = 1020 MeV. The angular distribution coefficients together with the total cross section are compared with the calculation of the isobar model by using the impulse approximation. Although the spin and parity of the resonance cannot be determined unambiguously, a negative parity assignment gives better fit to the data.