Four-Loop Anomalous Dimensions for Radiative Flavour-Changing Decays

We evaluate the complete four-loop anomalous dimension matrix that is necessary for determining the effective flavour-changing neutral current couplings qbar-q'-gamma and qbar-q'-g at the next-to-next-to-leading order in QCD. The resulting O(alpha_s^2(mu_b)) correction to the B -> X_s g...

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Detalles Bibliográficos
Autores principales: Czakon, M, Haisch, U, Misiak, M
Lenguaje:eng
Publicado: 2006
Materias:
Particle Physics - Phenomenology
Acceso en línea:https://dx.doi.org/10.1088/1126-6708/2007/03/008
http://cds.cern.ch/record/1007759
Descripción
Sumario:We evaluate the complete four-loop anomalous dimension matrix that is necessary for determining the effective flavour-changing neutral current couplings qbar-q'-gamma and qbar-q'-g at the next-to-next-to-leading order in QCD. The resulting O(alpha_s^2(mu_b)) correction to the B -> X_s gamma branching ratio amounts to around -2.9% for mu_b = 5 GeV, and -4.4% for mu_b = 2.5 GeV

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