Top and Higgs decays: looking for quantum SUSY signatures in hadron colliders

Abstract

I present an updated discussion of the one-loop corrections to the standard top quark decay, t-> W^+ b, and to the charged Higgs mode, t-> H^+ b, within the framework of the MSSM. These higher order contributions to the top width are compared with the direct top decays into 2 and 3 real SUSY particles. It turns out that whereas the SUSY effects on t-> W^+ b add up to those from standard QCD, they tend most likely to erase the conventional QCD corrections to t-> H+ b. However, in the latter case the full (strong plus electroweak) SUSY quantum effects are generally so large that the QCD corrections effectively come out with the ``wrong sign''. A qualitatively distinct, and quantitatively significant, ``quantum signature'' of that type might constitute a most sought-after imprint of ``virtual'' Supersymmetry, which remains sizeable enough even in the absence of any direct top decay into SUSY particles. Similar considerations are made for the hadronic partial widths of the Higgs bosons of the MSSM. While a first valuable test of these effects could possibly be performed at the upgraded Tevatron, a more precise verification would most probably be carried out in future experiments at the LHC.