Search for the flavor changing neutral current decay top quark going to quark-Z boson in proton-antiproton collisions at center of mass energy = 1.96 TeV.

摘要

This dissertation presents a blind search for the flavor changing neutral current decay of the top quark t → qZ in pp collisions at s = 1.96TeV using a data sample corresponding to an integrated luminosity of 1.12 fb-1 collected by the Collider Detector at Fermilab (CDF), This decay is extremely rare in the standard model, and a signal at the Tevatron would be an indication of new physics. Dividing candidate events with a Z boson and four or more jets into a sample of those which have a heavy flavor jet identified by a secondary vertex algorithm and those which do not, we observe data yields consistent with background expectations. We set a 95% C.L. upper limit on the branching fraction B (t → qZ) of 11.3%, consistent with an expected upper limit of 7.8% +/- 3.3%.