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The radiative Σ → nπ γ decay mode was analysed in the 81 cm SACLAY hydrogen bubble chamber exposed to a stopping K beam at the CERN PS. The pion spectrum was measured up to momenta of 150 MeV/c in the Σ rest frame. We obtain the following branching ratios based on 180 Σ→nπγ and 292 Σ→ nπγ events: Γ(Σ → nπ γ)/Γ(Σ→nπ)=(0.93±0.10)×10 Γ(Σ→nπ γ)/Γ(Σ→nπ)=(0.46±0.06)×10. An unambiguous assignment of S-wave to the Σ→nπ and P-wave to Σ→nπ was obtained. The absolute and differential decay rates as well as the parity assignments are in good agreement with theoretical predictions. [ABSTRACT FROM AUTHOR]

In a bubble chamber experiment about 2×10 Σ-decays have been measured to separate Σ→ne¯ ν events from the two-body modes. No Σ →ne ν event was found whereas 607 Σ→ne¯ ν decays could be identified. The data yield for the Δ Q=−Δ S decay an upper limit: and the branching ratio: [ABSTRACT FROM AUTHOR]

Saturation and hue perceived in monochromatic stimuli and in light mixtures were scaled psychophysically by a direct magnitude estimation method. The colors were of aperture mode and were presented against a dark background. As a result opponent-colors functions were obtained which show the hue sensations produced by the lights of the visible spectrum (under the observing conditions used). Compared to the opponent-colors functions of Hurwich and Jameson, obtained by a cancellation technique, the subjective hue sensation differed significantly. It may be concluded that these cancellation functions describe an earlier, probably a retinal level of data processing, while our results may be regarded as a description of the output of the color vision system.