Backward production of the B meson in K−p interactions at 4.2 GeVc

The backward production of the B(1235) meson is studied in the reaction K^?p→Σ^?π⁺ω. This reaction is observed in the final state Σ^?π⁺π⁺π^?π⁰. A π⁺ω mass enhancement is visible in the region of the B meson for events with small |u|K^? →Σ^?) squared four-momentum transfer. The properties of the enhancement agree with those of the B meson. The cross section for K^?p→Σ^?B⁺ at $\text{4.15}\text{GeV}\text{c}$ incident K^? momentum is (3.2 ± 0.5) μb. The backward production of the B meson is compared with similar baryon exchange productions of the A₁ and C(Q₁) axial vector mesons observed in the same experiment.     

Anomalous conductivity effects in (Na,K) mixed crystals of the β-Al2O3 type

Anomalous behavior has been observed in the ionic conductivity of (Na,K) mixed crystals of the alkali gallates and aluminate of the β-Al₂O₃ type fast ion conductors. The conductivity goes through a minimum at some intermediate composition as a consequence of a maximum in the activation energy, and is most pronounced in the (Na,K)-β-gallate, followed by (Na,K)-β-Al₂O₃ and (Na,K)-β“-gallate. The effect is similar to the well-known “mixed alkali effect” in glasses. A second anomaly consisting of a pronounced increase in conductivity over about a 70° temperature range, without any permanent change in activation energy, was observed for some compositions of (Na,K)-β“-gallate.     

Electroproduction of π0 mesons in the resonance region at q2=1.0 (GeV/c)2

Data are presented for the reaction ep → epπ⁰ at a nominal momentum transfer squared of 1.0 (GeV/c)². The data were obtained using an extracted electron beam from NINA and two magnetic spectrometers for coincidence detection of the electron and proton. Differential cross sections have been measured for isobar masses in the range 1.19–1.73 GeV/c².     

Studies of prereactions during MOVPE growth of wide band-gap II/VI semiconductors: the effect of pyridine upon the gas-phase reactions between H2S and Me2Zn

The effect of pyridine addition upon the gas-phase reactions of hydrogen sulphide (H₂S) with dimethylzinc (Me₂Zn) in the presence of pyridine has been investigated and compared with results from reactions of H₂S with Me₂Cd. The deposits of ZnS which form have been analysed and consist of particles in the nanocrystalline size range of mainly the hexagonal phase. The average particle size within the deposits depends on both the concentration of pyridine in the gas phase and the temperature at which the reactants are mixed. Pyridine may bind through the lone pair of the nitrogen to surface metal atoms of growing particles, inhibiting further growth of the particle.     

Digermanium polycobalt carbonyls formed by addition reactions of GeH bonds: [Co4(CO)13Ge(GeMe2)] and [Co6(CO)20Ge2]

GeMe₂H₂ reacts under mild conditions with [{Co₂(CO)₇}₂Ge] to replace one bridging CO and give [Co₄(CO)₁₃Ge(GeMe₂)]. GeH₄ similarly yields a trace of [Co₆(CO)₂₀Ge₂], which may be made in high yield from [Co₂(CO)₈] and Ge₂H₆ or Me₂Si(GeH₃)₂. Spectroscopic evidence suggests structures of linked GeCo₂ triangles.     

π − ω interference in the reactions K− p → π+ π− (Λ, ϵ0) at 4.2 GeV/c

π ? ω interference is studied in the reactions K^? p → π⁺ π^? (Λ⁰, ?) at 4.2 GeV/c using data from a high statistics experiments in the CERN 2m HBC. The phenomenon is analysed in terms of the conventional formalism as well as in terms of a new model for π ? ω interference proposed by Earles and Srivastava. Satisfactory agreement with the data is found for both models. The rate of ω → 2π obtained in the latter model is in agreement with the VMD (Vector Meson Dominance) prediction for ω → γ → ? → 2π.