Positronium-Ion Decay

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-)=2.087 963(12)/ns. We include O(alpha2) 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.

Experimental progress in positronium laser physics

“…This method is not very efficient, converting only 0.028% of the incident positrons into Ps − ions [509]. The same methodology as developed by Mills was used in further decay rate measurements carried out by researchers at Heidelberg University [540][541][542], who obtained Γ = 2.0875(50) ns −1 , in very good agreement with the calculated value of Γ = 2.087963(12) ns −1 [520]. In all of these experiments a d.c. positron beam was used to produce Ps − ions that are immediately accelerated by a large electric field.…”

“…The most accurate calculated Ps − decay rate is Γ = 2.087963(12) ns −1 [520]. The spatial Ps − wave function is symmetric with respect to the two electrons, and so for the total wave function to be antisymmetric the electrons must be in a singlet state.…”

“…[516,517]). Ps ions have been the subject of much theoretical work since Wheeler's paper [16], including studies of their decay rates [514,[518][519][520] and binding energies [521][522][523][524][525][526].…”

Positronium negative ion experiments – formation, photodetachment and production of an energy tunable positronium beam–

“…Although Mills did not obtain the final result, Fleischer et al [16] determined the decay rate using the same method in 2006. Their value was 2.089(15)ns −1 , which is consistent with recent theoretical results [8,10].…”

“…Since the prediction by Wheeler, many theoretical studies have been performed to explore the nature of Ps − . For example, the ground-state energy and the annihilation rate have been calculated [3]- [10] and the photodetachment process has been studied [11]- [13]. However, measurements of the decay rate have been the only experiments performed for many years [14]- [16] because of extremely low Ps − intensities.…”