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arXiv · hep-ph/0305251

Two-loop corrections to the decay rate of parapositronium

Gregory S. Adkins·Nathan M. McGovern·Richard N. Fell·J. Sapirstein
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Abstract

Order $α^2$ corrections to the decay rate of parapositronium are calculated. A QED scattering calculation of the amplitude for electron-positron annihilation into two photons at threshold is combined with the technique of effective field theory to determine an NRQED Hamiltonian, which is then used in a bound state calculation to determine the decay rate. Our result for the two-loop correction is $5.1243(33)$ in units of $(α/π)^2$ times the lowest order rate. This is consistent with but more precise than the result $5.1(3)$ of a previous calculation.

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Gregory S. Adkins, Nathan M. McGovern, Richard N. Fell, J. Sapirstein. 2003-05-22. Two-loop corrections to the decay rate of parapositronium. https://doi.org/10.1103/physreva.68.032512

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