1. Feasibility of Detecting Leptoquarks With the CDF Detector Althea Moorhead Mentor: Darin Acosta

2. Outline Background: What is a leptoquark? Leptoquark production and previous work Results & Calculations Conclusions

3. The Standard Model Quarks, leptons, and gauge particles (force carriers) Arranged into three generations Why is there a correlation between quarks and leptons?

4. Leptoquarks Predicted by grand unified theories, supersymmetry, and string theory Would be bosons Would have characteristics of both quarks and leptons

5. Leptoquark Production Gauge Coupling Mediated by gauge bosons Yukawa Coupling Direct fusion of a lepton and a quark

6. The Tevatron Proton-antiproton collider Energy of 1 TeV (most energetic in the world) Run 1: 100 pb -1 Run 2: 2000 pb -1

7. The CDF Detector Tracking chamber maps the trajectories of charged particles Calorimeters measure particle energies

8. Background: Current Leptoquark Limits Leptoquarks decay into a lepton and a quark. Probability of that lepton being charged is the branching ratio . Interested in region of small .

9. Procedure Simulate leptoquark and background events PYTHIA – event simulation cdfSim – detector simulation Production – event reconstruction Stntuple – event analysis Use cuts to differentiate between signal and background

10. Missing Transverse Energy LeptoquarkBackground

11. Table of Expected Events TypeNobs Leptoquark:100 GeV58 150 GeV14 Background:QCD195 W100 W+jets67 Z36 Z+jets20 Top quark7

12. Sensitivity vs. Missing Energy The statistical significance: Statistical significance not very dependent on the missing energy

13. Sensitivity vs. Min. Jet Energy Statistical significance is dependent on the minimum jet energy Peak at about 35 GeV

14. Other Cuts

15. Cross Section Upper Limits Find upper limits on leptoquark events, then:

16. Projected New Limits

17. Mass Limit vs. Luminosity

18. Conclusions Results consistent with previous work Experimental data will change these results somewhat Could be improved with heavy flavor tagging