1. The Physics of Generations Don Lincoln f

2. Four Fermion General ‘Theory’ Theory consists of all terms of any chiral combinations Drell-Yan Only

3. Tevatron Run I Limits Drell-Yan QCD Units: TeV

4. Topics Currently Covered All p p  two particles –p p      (p  resolution limited) –p p  e  e   visa problems) –p p  e  (MET questions) –p p  b b (two tagging approaches) –p p  jet-jet (most robust) –d  /dM & d  /d(cos  *)

5. Run II Projected: Dijet Mass Spectrum Dramatic increase in high p T cross sections Large gains in statistics

6. Run II: Drell-Yan Constructive Interference Destructive Interference Projected Limits (Bayesian) PRL 82 4769 (1999)

7. 2VTX Tagging High P  b Jets Don Lincoln f Isn’t that two there? Kapow!

8. Motivation Fit to CDF qQCD calculation CDF: PRL 82 (1999) 2038 High mass b b pairs can be sign of new physics (compositeness ?) Problem –~100:1 QCD:b b Solutions  tagging –2 nd VTX tagging –Impact parameter

9. Current Work DCA Decay Length Key Calorimeter Jet b hadron Secondary vertex Primary vertex Particles of Interest Question: Is failure to reconstruct secondary vertex due to tracking efficiency or vertex algorithm? Many variables have been tried for 2 VTX tag Decay length & significance (2D & 3D) Vertex Mass   R etc. Only decay length and related quantities works. Consider other tags eventually. RR Impact Parameter

10. What if ? We know that one can find secondary vertices by accident in light quark initiated events Estimate Eff(right) ~ Eff(found) - Eff(light) No light statistics at high pt Reality could be worse Eyeball trends and guess. Eff(found) = Eff(luck) + Eff(right) Efficiency only that of finding a ‘good’ secondary vertex

11. Decay Length (found and 2VTX) Found = found track 2VTX = used in secondary vertex Ptmin(track) = 500 MeV Efficiency = 2VTX/found Efficiency ~ Pt and flavor-initiator independent

12.  R (real and found) Found = correct + fake Ptmin(track) = 500 MeV Efficiency = found/real Light quark jets has better tracking efficiency in core.

13. Tracking ‘Efficiency’ vs Pt.

14. Summary Several different high mass di-object searches underway In b b –Need to understand tracking efficiency in core of jets –Need to look more at muon tagging (but low mass reach) –Need to better understand b quark content from parton showers. Active effort Need more people thinking about it.