Speaker: Min Jeong Kim (CHEP Korea / FNAL)

Date: Wed Apr 11, 2001, 4.30 pm 
Location: Wean 7316

Title: A Search for R-parity Violating Scalar Top Quark Decays 
       in Proton-Antiproton Collisions 


Abstract: 
We present a search for the lightest scalar top quark a supersymmetric
partner of the top quark, using proton-antiproton collision data collected
in 1992-95 by the CDF detector at sqrt{s} = 1.8 TeV.
We assume the scalar top quarks are produced in pairs, followed by the 
R-parity violating decays into a tau lepton and a bottom quark via a
non-zero lambda'_333 coupling. Therefore, the experimental signature is two
tau leptons and two b quark jets. Events are inclusively selected by
requiring a letpon, where the lepton is an electron or a muon, a
hadronically decaying tau lepton, and two jets. We observed no candidate
events in the data using our event selection criteria, which are consistent
with the Standard Model expectations. We set a 95% confidence level lower
limit of the mass of stop quarks at 119 GeV by comparing our measurement to
the next-to-leading order theoretical calculations.