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Particles and Fields
Eur. Phys. J. C 29, 191-195 (2003)
DOI: 10.1140/epjc/s2003-01212-7

General formulae for $f_1 \to f_2 \gamma$

L. Lavoura

Universidade Técnica de Lisboa, Centro de Física das Interacções Fundamentais, Instituto Superior Técnico, 1049-001 Lisboa, Portugal

(Received: 24 February 2003 / Revised version: 26 March 2003 / Published online: 2 June 2003)

At one-loop level the decay $f_1 \to f_2 \gamma$, where f1 and f2 are two spin- 1/2 particles with the same electric charge, is mediated by a boson B and a spin- 1/2 fermion F. The boson B may have either spin 0 - interacting with the fermions through the Dirac matrices 1 and $\gamma_5$ - or spin 1 - with V+A and V-A couplings to the fermions. I give general formulae for the one-loop electroweak amplitude of $f_1 \to f_2 \gamma$ in all these cases.

© Società Italiana di Fisica, Springer-Verlag 2003