Rare Exclusive Decays of Electroweak Bosons in QCD Factorization
Matthias Koenig
Mainz U.
I will discuss the rare, exclusive hadronic decays of Z, W and Higgs bosons in the framework of QCD factorization. The factorization formula is derived in Soft-Collinear Effective Theory, exploiting the scale separation between the hard scattering scale and hadronization scale. Due to the fact that the hard scale is set by the decaying heavy boson, power corrections are well under control. Additionally, RG effects lower the sensitivity of the amplitude to the hadronic input parameters. This means that at a possible future Z-factory, decays like Z -> M gamma can be used to test the QCD factorization approach in a theoretically clean environment. I will also discuss the case of hadronic Higgs decays, where cancellations between different diagram topologies lead to interesting sensitivities to possible new physics effects in Higgs couplings.