A Silicon Vertex Detector for CDF

The major reason for building a vertex detector for CDF is the tagging of decay vertices of particles with lifetime in the 10-13/10-12 sec. range. This is a complementary approach to heavy flavour physics with respect to missing Et and large Pt leptons. The method can be best applied to tag hadronic decays of heavy flavours, which have the largest branching ratios, but have eluded any specific tagging until now. It also works, although with somewhat reduced efficiency, in events with a semileptonic decay. All in all it promises to be a powerful tool in the search of rather elusive processes like Higgs, top, or fourth generation quark production [1]. The additional information provided by the vertex detector will also improve significantly the resolution of the CDF central tracking system [2].