G. Zech

Elastic Σ±p scattering at low energies

Abstract Total and differential elastic Σ ± p scattering cross sections have been measured in the momentum interval of 130–180 MeV/ c . From the Σ ± p total cross section allowed regions for the singlet and triplet scattering lengths are derived, applying the effective range approximation.

Measurement of the Σ0 lifetime

Abstract The Coulomb production of Σ 0 hyperons on uranium and nickel nuclei has been measured in a beam of Λ hyperons at the CERN Proton Synchrotron. The results for the Σ 0 lifetime, τΣ 0 =(0.58 ± 0.13) × 10 −19 sec, and for the Σ 0 -Λ magnetic transition moment, | μΣ Λ | = (1.82 −0.18 +0.25 ) nuclear magnetons, are in agreement with SU(3) predictions.

Fit of the parameters for Cabibbo's theory

AbstractAll experimental data on leptonic decays of Baryons available after the Kiev Conference on High Energy Physics (Sept. 1970) are used to fit the parameters of the Cabibbo theory. Especially new results on σ− and Λ leptonic decays and the values of the Σ± lifetime are included.The data are consistent with the one angle Cabibbo theory. The results for the three parameters are:

A measurement of the total cross-sections for Λ hyperon interactions on protons and neutrons in the momentum range from 6 GeV/c to 21 GeV/c

\begin{gathered} \theta = 0.239 \pm 0.005 \hfill \\ g_1^F = 0.451 \pm 0.019 \hfill \\ g_1^D = 0.777 \pm 0.021. \hfill \\ \end{gathered}

Measurement of the charge asymmetry in the decays KoL → π±e±ν and KoL → π±μ±ν

Abstract The change asymmetry in semi-leptonic kaon decays has been measured as a function of the kaon lifetime. High statistics data of K e3 0 and K μ3 0 decay modes agree with each other and with the general expectation of the CP violation phenomenology together with the ΔS − ΔQ rule. The K L -K S mass difference obtained is Δm = (0.533 ± 0.004) × 10 10 s −1 .

Measurement of the vector form factor in the decay KL → πev

Abstract The Λp, Λn, Λ p, and Λ n total cross-sections were measured in the Λ momentum interval 6–21 GeV/ c . Within the experimental uncertainties the cross-sections are momentum-independent in this interval and the momentum-averaged cross-sections are found to be: σ ( Λp ) = 34.6 ± 0.4 mb : σ ( Λn ) = 34.0 ± 0.8 mb ; σ ( Λp ) = 56 ± 11 mb ; σ ( Λn ) = 46 ± 20 mb . The first two results are in agreement with charge symmetry, and with simple quark model sum rules applied to previous results on pp, K - n, and π + p total cross-sections.

Determination of the Σ± → Λe±ν decay parameters

AbstractThe decay modesΣ±→nπ±γ, Σ+→pγ,Σ+→pe+e}- were studied in the 81 cm Saclay hydrogen bubble chamber. In the radiative decayΣ±→nπ±γ only low momentum pions which stop in the chamber were accepted.We obtain the following branching ratios:(1)