We calculate the asymmetry A cir = [ a ( + )-a( -)]/[a( + 1 +a( -11 for the reaction ?d+np, where a( + 1 [ a ( -) ] is the total cross section for right [left] circularly polarized photons. The calculation is carried out for photon energies up to 30 MeV above threshold in the laboratory system. The result for Acir is expressed in terms of the effective parity- violating N N v , N N p , and NNw coupling constants.

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Free volume of polystyrene films treated with supercritical carbon dioxide (SCCO 2) were examined by positron annihilation lifetime spectroscopy. Variation of the free volume sizes after the SCCO 2 treatment due to the release of trapped CO 2 and structural relaxation of the polymer was observed. After 500 h from the depressurization, the free volume of the treated films free from CO 2 was approximately 0.306 nm in radius and much larger than that of the untreated films of approximately 0.295 nm in radius due to the freezing of the swollen structure caused by the large solubility of CO 2.

Interlaboratory comparison of positron annihilation lifetime measurements using synthetic fused silica and polycarbonate was conducted with the participation of 12 laboratories. By regulating procedures for the measurement and data analysis the uncertainties of the positron lifetimes obtained at different laboratories were significantly reduced in comparison with those reported in the past.

Two-photon decay of the Higgs boson H→γγ and its reverse process γγ→H are important processes in detecting Higgs boson which plays a fundamental role in the Standard Model of electroweak interaction. We calculate the QCD corrections to these processes for all mass ranges of the Higgs boson without any constraint for the top quark mass. For a heavy Higgs boson (mH≫mt), the QCD corrections become very large (50–100%), while for a lighter one (mH≤mt), the corrections are negligible.

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Chemical reactions of a novel gauchetype spin trap, G-CYPMPO (sc-5-(5,5-dimethyl-2-oxo-1,3,2-dioxaphosphinan-2-yl)-5-methy-1-pyrroline N-oxide, O1–P1–C6–N1 torsion angle = 52.8°), with reactive oxygen species were examined by pulse radiolysis technique with 35 MeV electron beam and by electron spin resonance spectroscopy after 60Co γ-ray irradiation. The spin-trapping reaction rate constants of G-CYPMPO toward the hydroxyl radical and the hydrated electron were estimated to be (4.2 ± 0.1) × 109 and (11.8 ± 0.2) × 109 M–1s–1, respectively. Half-lives of the spin adducts, hydroxyl radical, and perhydroxyl radical adducted G-CYPMPO were estimated to be ∼35 and ∼90 min, respectively. A comparison of the results with earlier reports using different radical sources suggests that the purity of the solution and/or the radical generation technique may influence the stability of the spin adducts.