- Search for e+e- -> t qbar (Monica Pepe-Altarelli) ---------------------------------------------- Monica showed a earch for single top production via F.C.N.C. This may occur either with a photon or Z0 propogator in s-channel. CDF has very poor limits for these two possibilities from top decay. Their limits imply a cross-section at 183 GeV of < 0.1 pb. A MC program has been written to generate the signal events. The b and qbar are joined by a string. The W decays independently. The analysis looks for 4-jet events, tagging b jet from top decay and making cuts on the energy of the b jet and the reconstructed W mass. Cutting on the reconstructed top mass doesn't help. A second analysis also looks for signal events with a leptonic decay of the W. The selection efficiency is 13%. 1 event seen in data. 2.4 background events expected. => sigma < 0.6 pb. Not competitive with CDF, but should do better next year.
- Bhabha Monte Carlos at LEP2 (Marc Swynghedauw) ---------------------------------------------- Marc took a look at how well various Monte Carlos simulate Bhabhas at LEP2. BHWIDE does well. UNIBAB produces far too many events with hard ISR photons. It is therefore unreliable if the outgoing e+e- are not very back to back. Marc took at look at the UNIBAB code, and indeed the part used to simulate ISR looks very simplistic. BHAGEN96 is a new Monte Carlo - no results yet.
- Next meeting --->
Guenther Dissertori
Fri March 13, 17:30:38 MET DST 1998