Measurement of the branching ratio of the double Dalitz decayK L →e+e−e+e− and the CP parity of theK L -meson

Data from the NA31 experiment at CERN have been used to measure the branching ratio of the double Dalitz decay of the long-lived neutral kaon. Eight events have been found with negligible background. The measured distribution of the angle between the planes of the two e⁺e^?-pairs favours aCP=?1 state for the long-lived neutral kaon.     

The thiolate anion as a nucleophile part X. Reactions of some nitrofluoroaromatics

The reactions of various nitrofluorobenzenes, C₆H_xF_yNO₂, with sodium methanethiolate have been studied in ethylene glycol/pyridine mixture as solvent. All the fluorine atoms, but not the nitrogroups, could be substituted by the methylthio group. The reactions have also been studied with the addition of a deactivating group, either methyl or amino, on the aromatic nucleus. Some of the methylthio groups in the products were oxidized to the corresponding sulfones. The new compounds isolated have been characterized and their spectra (IR, NMR and mass) examined.     

Experimental limits on the form factors in K°μ3 decay

An analysis of 1385 K°_μ3 decays observed in a heavy liquid bubble chamber is presented, and limits are obtained on the form factors ξ(0) and λ₊. Assuming λ₊ to be 0,025, ξ(0) is found to be ?0.90 ± 0.45.     

The thiolate anion as a nucleophile Part IX. Reactions of some fluoroaromatics

The reactions of some halogenoaromatic compounds, mainly fluoroaromatics C₆F_xH_6-x with the methanethiolate anion have been studied in DMF or an HMPA/THF mixture. Complete replacement of fluorine occurred forming C₆(SMe)_xH_6-x. Attempts to prepare C₆(SEt)₆ and compounds such as C₆(SEt)₂(SMe)₄ are described. Other new compounds isolated included C₆(SMe)₅SH and C₆F₂(SMe)₂(SEt)₂. Details of the spectra, particularly NMR, are given.     

Mass spectra of the thioethers C6F5SC6H4X

The mass spectra of a number of thioethers of the type p-XC₆H₄SC₆F₅ (X = H, Cl, NO₂, SC₆F₅, CO₂C₂H₅, C₆H₅) have been examined. These spectra have been compared with those of (C₆H₅)₂S and (C₆F₅)₂S. Fragmentation patterns have been deduced from metastable peaks. The spectrum of p-ClC₆H₄SC₆F₅ has been studied in more detail.