103 research outputs found

    Photoproduction of Lambda(1405) and Sigma^{0}(1385) on the proton at E_\gamma = 1.5-2.4 GeV

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    Differential cross sections for γpK+Λ(1405)\gamma p \to K^+\Lambda(1405) and γpK+Σ0(1385)\gamma p \to K^+\Sigma^0(1385) reactions have been measured in the photon energy range from 1.5 to 2.4 GeV and the angular range of 0.8<cos(Θ)<1.00.8<\cos(\Theta)<1.0 for the K+K^+ scattering angle in the center-of-mass system. This data is the first measurement of the Λ(1405)\Lambda(1405) photoproduction cross section. The lineshapes of \LamS measured in Σ+π\Sigma^+\pi^- and Σπ+\Sigma^-\pi^+ decay modes were different with each other, indicating a strong interference of the isospin 0 and 1 terms of the Σπ\Sigma\pi scattering amplitudes. The ratios of \LamS production to \SigS production were measured in two photon energy ranges: near the production threshold (1.5<Eγ<2.01.5<E_\gamma<2.0 GeV) and far from it (2.0<Eγ<2.42.0 <E_\gamma<2.4 GeV). The observed ratio decreased in the higher photon energy region, which may suggest different production mechanisms and internal structures for these hyperon resonances

    Novel critical exponent of magnetization curves near the ferromagnetic quantum phase transitions of Sr1-xAxRuO3 (A = Ca, La0.5Na0.5, and La)

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    We report a novel critical exponent delta=3/2 of magnetization curves M=H^{1/delta} near the ferromagnetic quantum phase transitions of Sr1-xAxRuO3 (A = Ca, La0.5Na0.5, and La), which the mean field theory of the Ginzburg-Landau-Wilson type fails to reproduce. The effect of dirty ferromagnetic spin fluctuations might be a key.Comment: 4 pages, 5 figure
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