$O({\alpha }^2\Gamma ,{\alpha }^3\Gamma )$ binding effects in orthopositronium decay

We present a new, simplified analysis of the low-energy electron-positron interaction, and use the resulting effective theory to calculate the binding effects that contribute to the decay rate $\Gamma$ of orthopositronium through $O\left({\alpha }^3\ln \alpha \Gamma \right).\mathrm{}$ We express the total decay rate in terms of the annihilation rate for a free electron and positron at threshold, which has just recently been computed to sufficient precision. Our $O\left({\alpha }^2\Gamma \right)$ result corrects errors in a previous analysis.