First test of $O(\alpha ^{2})$ correction of the orthopositronium decay rate

TL;DR

This paper reports the first experimental validation of the second-order quantum electrodynamics correction to the orthopositronium decay rate, confirming theoretical predictions with high precision measurements.

Contribution

It provides the first experimental test of the $O(\alpha^2)$ correction in orthopositronium decay, aligning experimental results with advanced theoretical calculations.

Findings

Measurement accuracy of 150 ppm confirms second-order correction

Results are consistent with recent theoretical predictions

First validation of $O(\alpha^2)$ correction in orthopositronium decay

Abstract

Positronium is an ideal system for the research of the bound state QED. New precise measurement of orthopositronium decay rate has been performed with an accuracy of 150 ppm. This result is consistent with the last three results and also the 2nd order correction. The result combined with the last three is 7.0401$\pm0.0007\mu \mathrm{sec}^{-1}$ (100 ppm), which is consistent with the 2nd order correction and differs from the 1st order calculation by 2.6$\sigma$ It is the first test to validate the 2nd order correction.