Study of the reactione + e −→K + K − in the energy range1350 \leqq \sqrt s \leqq 2400 MeV

Thee ⁺ e ^?→K ⁺ K ^? cross section has been measured from about 750 events in the energy interval \(1350 \leqq \sqrt s \leqq 2400 MeV\) with the DM2 detector at DCI. TheK ^± form factor |F _F ^±| cannot be explained by the ρ, ω, ? and ρ′(1600). An additional resonant amplitude at 1650 MeV has to be added as suggested by a previous experiment.     

The electron-hole mechanism for sticking of adsorbates: A soluble model

It is shown that in the low temperature limit the electron hole dissipation mechanism recently considered by Nørskov and Lundqvist leads to a limiting sticking probability independent of adsorbate mass but dependent on adsorbate-substrate coupling strength. The dependence of sticking probability on initial adsorbate kinetic energy is also determined.     

Radiative decay ofJ/ψ into γ π+ π−

The radiative decayJ/ψ → γ π⁺ π^? has been studied using the 8.6 millionJ/ψ produced in the DM2 experiment at the DCIe ⁺e^? storage rings at Orsay. The π⁺ π^? mass spectrum shows a cleanf ₂ (1270) signal, and the possible presence of two other states at thef ₂ (1720) andf ₄ (2030) masses. For thef ₂ (1270), the branching ratio BR(J/ψ →γf)xBR(f→π⁺ π^?) is measured to be (7.50±0.30±1.12)×10^?4, and the spin analysis prefers theJ=2 assignment, with helicity parametersx=0.83±0.06 andy=0.01±0.06. The existence of higher mass states is discussed.     

Non-planar smoulder propagation governed by diffusion

The steady propagation of a thin smouldering front in a half-spacehas been considered. A suitable coordinate transformation hasallowed the region near the leading edge of the front to beexamined for both a maintained planar surface and with surfacecollapse due to material shrinkage. The change in the oxidizerconcentration for a small increment in the propagation speedfor large time and surface collapse has been determined. Theinfluence of two types of nonlinear diffusion on the shape ofthe smouldering front has been found; other cases can be dealtwith in a similar manner.     

Absorption losses in glasses and glass fibre waveguides

Glasses prepared from high purity starting materials were used for pulling optical waveguide fibre by a double crucible technique. The observed optical loss of the glasses and fibres can be accounted for by absorption bands arising from the presence of traces of transition metal ion impurities and the low energy tails of u.v. absorption bands. The relatively high loss of the fibres is attributed to leaching of impurities from the platinum crucibles.     

Relaxation shifts and plasmon excitation in absorption spectroscopy of adsorbed atoms

The excitation probability for surface plasmons, and the level shift due to the image force, are investigated when an electron is excited from a core level to an unoccupied virtual level of the adatom. The results differ strongly from the corresponding ones in XPS, in a manner depending on the energy variation of the width of the virtual level.