Positronium-ion decay

TL;DR

This paper provides a highly precise theoretical prediction for the decay width of the negative positronium ion, including second-order quantum electrodynamics effects, and prepares for experimental validation.

Contribution

It presents the first calculation of second-order corrections to the decay of a three-particle bound state, specifically the negative positronium ion.

Findings

Predicted decay width: 2.087 085(12)/ns

Includes O(alpha^2) effects of virtual photons

First second-order correction for three-particle bound state

Abstract

We present a precise theoretical prediction for the decay width of the bound state of two electrons and a positron (a negative positronium ion), Gamma(Ps^-) = 2.087 085(12)/ns. We include O(alpha^2) effects of hard virtual photons as well as soft corrections to the wave function and the decay amplitude. An outcome of a large-scale variational calculation, this is the first result for second-order corrections to a decay of a three-particle bound state. It will be tested experimentally in the new positronium-ion facility in Garching in Germany.