Low-energy quenching of positronium by helium

Abstract

Very low-energy scattering of orthopositronium by helium has been investigated for simultaneous study of elastic cross section and pick-off quenching rate using a model exchange potential. The present calculational scheme, while agrees with the measured cross section of Skalsey et al, reproduces successfully the parameter $^ 1Z_{\makebox{eff}}$, the effective number of electrons per atom in a singlet state relative to the positron. Together with the fact that this model potential also leads to an agreement with measured medium energy cross sections of this system, this study seems to resolve the long-standing discrepancy at low energies among different theoretical calculations and experimental measurements.

4 latex pages, 3 postscript figures

References in corpus (2)

• Electron exchange model potential: Application to positronium-helium scattering
• Positronium-hydrogen-atom scattering in a five-state model

Cited by in corpus (9)

• Effect of H${}^{-}$ ion formation on Positronium-Hydrogen elastic scattering
• Differential cross sections for elastic and inelastic positronium-hydrogen-atom scattering
• Differential and partial cross sections of elastic and inelastic positronium-helium-atom scattering
• Variational calculation of positronium-helium-atom scattering length
• S-, P- and D-wave resonances in positronium-sodium and positronium-potassium scattering
• Low-energy direct muon transfer from H to Ne${}^{10+}$, S${}^{16+}$ and Ar${}^{18+}$ using two-state close-coupling approximation to Faddeev-Hahn-type equation
• Positronium scattering by atoms and molecules at low energies
• Resonances in positronium-rubidium and positronium-cesium scattering
• Quenching of $para$-H${}_2$ with an ultra-cold anti-hydrogen atom ${\bar{H}}_{1s}$