Nonfactorizable QCD and Electroweak Corrections to the Hadronic Z Boson Decay Rate

TL;DR

It is found that the naive factorization of QCD and electroweak corrections does not describe correctly the two-loop effects and the nonfactorizable corrections shift the width of the Z boson and increase the central value of the strong coupling constant determined at the CERN LEP.

Abstract

We present an analysis of two-loop mixed QCD and electroweak corrections to the decay of the Z boson into light quarks. We find that the naive factorization of QCD and electroweak corrections does not describe correctly the two-loop effects. The nonfactorizable corrections shift the width of the Z boson by approximately -0.55(3) MeV and increase the central value of the strong coupling constant determined at LEP by 0.001.

Figures (4)

• Figure 1: One-loop electroweak corrections to the width of the $Z$ boson
• Figure 2: QCD corrections to the diagram 1(a)
• Figure 3: QCD corrections to the diagram 1(b)
• Figure 4: QCD corrections to the diagram 1(c)