Many-body theory for positronium scattering and pickoff annihilation in noble-gas atoms

Abstract

The many-body-theory approach to positronium-atom interactions developed in [Phys. Rev. Lett. \textbf{120}, 183402 (2018)] is applied to the sequence of noble-gas atoms He-Xe. The Dyson equation is solved separately for an electron and positron moving in the field of the atom, with the entire system enclosed in a hard-wall spherical cavity. The two-particle Dyson equation is solved to give the energies and wave functions of the Ps eigenstates in the cavity. From these, we determine the scattering phase shifts and cross sections, and values of the pickoff annihilation parameter ${}^1{Z}_{\text{eff}}$ including short-range electron-positron correlations via vertex enhancement factors. Comparisons are made with available experimental data for elastic and momentum-transfer cross sections and ${}^1{Z}_{\text{eff}}$. Values of ${}^1{Z}_{\text{eff}}$ for He and Ne, previously reported in [Phys. Rev. Lett. \textbf{120}, 183402 (2018)], are found to be in near-perfect agreement with experiment, and for Ar, Kr, and Xe within a factor of 1.2.

arXiv comment22 pages

References in corpus (13)

• Many-body theory of positron-atom interactions
• Positron scattering and annihilation on noble gas atoms
• Many-body theory of positron binding in polyatomic molecules
• Scattering of positronium by H, He, Ne, and Ar
• $\gamma$-ray spectra and enhancement factors for positron annihilation spectra with core-electrons
• o-Positronium scattering off H and He
• Formation of positron-atom bound states in collisions between Rydberg Ps and neutral atoms
• Ps-atom scattering at low energies
• Positronium-Atom Collisions
• Many-body theory for positronium-atom interactions
• Calculations of positronium-atom scattering using a spherical cavity
• Positronium collisions with rare-gas atoms
• Effective radius of ground- and excited-state positronium in collisions with hard walls

Cited by in corpus (3)

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