Formation of positron-atom bound states in collisions between Rydberg Ps and neutral atoms

TL;DR

This paper proposes a new experimental method to detect positron-atom bound states using Rydberg positronium collisions, providing theoretical estimates of cross sections and feasibility for experimental observation.

Contribution

It introduces a novel scheme for observing positron-atom bound states through Rydberg Ps collisions and provides detailed cross section calculations for experimental validation.

Findings

Estimated charge-transfer cross sections for various atoms and energies.

Predicted Ps ionization cross sections under different conditions.

Feasibility analysis for experimental detection of bound states.

Abstract

Predicted twenty years ago, positron binding to neutral atoms has not yet been observed experimentally. A new scheme is proposed to detect positron-atom bound states by colliding Rydberg positronium (Ps) with neutral atoms. Estimates of the charge-transfer reaction cross section are obtained using the first Born approximation for a selection of neutral atom targets and a wide range of incident Ps energies and principal quantum numbers. We also estimate the corresponding Ps ionization cross section. The accuracy of the calculations is tested by comparison with earlier predictions for Ps charge transfer in collisions with hydrogen and antihydrogen. We describe an existing Rydberg Ps beam suitable for producing positron-atom bound states and estimate signal rates based on the calculated cross sections and realistic experimental parameters. We conclude that the proposed methodology is capable of producing such states and of testing theoretical predictions of their binding energies.