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Developments with the Cone Algorithm in Run II

Developments with the Cone Algorithm in Run II. John Krane Iowa State University. Part I: Data vs MC, interpreted as physics Part II: Data vs MC, interpreted as a tuning problem. MC Workshop Oct. 4 2002, Fermilab. Lost Jets and Search Cones. CDF: Matthais Toennesmann DØ: John Krane

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Developments with the Cone Algorithm in Run II

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  1. Developments with the Cone Algorithm in Run II John Krane Iowa State University Part I: Data vs MC, interpreted as physics Part II: Data vs MC, interpretedas a tuning problem MC Workshop Oct. 4 2002, Fermilab

  2. Lost Jets and Search Cones • CDF: Matthais Toennesmann • DØ: John Krane Cones can iteratate away from “small” Energy clusters • There is a reason I’m showing the CDF image John Krane -- DØ

  3. Best Description of Procedure • Use a small cone to find jets and iterate locations • Expand cone size to full 0.7 and save • Find midpoints • Iterate 0.7 size midpoint jets • Wanted to check CDF’s solution and provide feedback John Krane -- DØ

  4. Results on selected sample (45 evts) Each point was a seed Seed tracking on a sample of 45 suspicious events Distance of nearestfound jet from original seed Symmetric in y-f, so just use R... Abs f drift Abs y drift John Krane -- DØ

  5. Drift distance for 0.7 cones, pT>15 GeV • If a seed is too close (R/2) to existing jet, ignore it • Standard cones can drift very long distances! • Search cone R/2 limits drift to R John Krane -- DØ

  6. R=0.5 Cones Same comments apply... John Krane -- DØ

  7. R=0.3 cones Again... John Krane -- DØ

  8. Normalize drift distances by R • R=0.5 cones,scaled distance John Krane -- DØ

  9. x-axes have suppressed zero John Krane -- DØ

  10. CPU Requirements John Krane -- DØ

  11. Conclusions for Search Cones • Cones can drift quite far from the seed, even for reasonably high-pT Jets >15 GeV • This doesn’t mean a jet is “lost” every time this happens (I have yet to find a lost jet in DØ data) • Search cones can limit drift as much as we like • R/2 works well (almost perfectly) "R John Krane -- DØ

  12. Suggestions for Future Work • Run full Reco tests for CPU time and consistency • Consult CDF and try to converge on a parameter • Informally, Joey Huston thinks R/2 works well • Would like permission to show this talk externally John Krane -- DØ

  13. Inclusive Jet and Dijet Mass John Krane -- DØ

  14. Integrated Luminosity for Moriond John Krane -- DØ

  15. Current Jet Triggers John Krane -- DØ

  16. Future Jet Triggers John Krane -- DØ

  17. John Krane -- DØ

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