EPJ

2023 Impact factor 4.2
EPJ C - Particles and Fields
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

Abstract
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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