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Two-loop electroweak top corrections: are they under control?

The assumption that two-loop top corrections are well approximated by the O(G_mu^2 mt^4) contribution is investigated. It is shown that in the case of the ratio neutral-to-charged current amplitudes at zero momentum transfer the O(G_mu^2 mt^2 M_Z^2) terms are numerically comparable to the m_t^4 cont...

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Detalles Bibliográficos
Autores principales: Degrassi, G., Fanchiotti, S., Feruglio, F., Gambino, P., Vicini, A.
Lenguaje:eng
Publicado: 1994
Materias:
Acceso en línea:https://dx.doi.org/10.1016/0370-2693(95)00268-P
http://cds.cern.ch/record/274401
Descripción
Sumario:The assumption that two-loop top corrections are well approximated by the O(G_mu^2 mt^4) contribution is investigated. It is shown that in the case of the ratio neutral-to-charged current amplitudes at zero momentum transfer the O(G_mu^2 mt^2 M_Z^2) terms are numerically comparable to the m_t^4 contribution for realistic values of the top mass. An estimate of the theoretical error due to unknown two-loop top effect is presented for a few observables of LEP interest.