2021 Impact factor 4.991
Particles and Fields
Eur. Phys. J. C 5, 535-543
DOI 10.1007/s100529800864

Some $\textstyle\protect\rm O(\alpha^2)$annihilation type contributions
to the orthopositronium width

V. Antonelli1 - V. Ivanchenko2 - E. Kuraev3 - V. Laliena1

1 Institute for Theoretical Physics, University of Bern, Sidlerstrasse 5, 3012 Bern, Switzerland
2 Institute of Nuclear Physics, Siberian Division, 630090 Novosibirsk, Russia
3 JINR, 141980 Dubna, Russia

Received: 10 December 1997 / Published online: 24 March 1998

We consider some radiative corrections to the lowest order annihilation diagram for the orthopositronium decay rate. The insertion of the renormalized vertex correction in the annihilation graph gives $1.6278 \ (\alpha/\pi)^2\,
\Gamma_0$. We compute also the contribution of the square of the lowest order annihilation amplitude, which turns out to be $0.1702\,(\alpha/\pi)^2\,\Gamma_0$.Finally, we obtain a term $\alpha^2\,\ln\alpha\,\Gamma_0$ arising from the correction to the light-light scattering block due to the exchange of one coulombic photon, in agreement with earlier computations.

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