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CPSReco Deghosting

CPSReco Deghosting. John Gardner University of Kansas Feb. 2003. Since p13, deghosting is in CPSReco but turned off. Should it be turned on?. Ghosts. f. z. - four 3D clusters formed: three from tracks, one is a ghost. - remove ghosts by limiting number of times a subcluster can be used.

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CPSReco Deghosting

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  1. CPSReco Deghosting John Gardner University of Kansas Feb. 2003 Since p13, deghosting is in CPSReco but turned off. Should it be turned on?

  2. Ghosts f z - four 3D clusters formed: three from tracks, one is a ghost - remove ghosts by limiting number of times a subcluster can be used - use cuts based on position and energy matching quality to decide what to remove

  3. 2 Matching Qualities for 3D clusters phix - phiuv position) matchquality = resolution u subcluster phix x subcluster phiuv f z v subcluster 2 r2 - 1/3 Ö ) ( E ₢ i i , r = energy) Ematchqual = r (1-r ) E i i i total 3 layers

  4. Parameters and Cuts ttbar MC event - in cases like this, limiting a subcluster to one use is too harsh - to ease cut: -for every 3D cluster, define mq_frac(eq_frac) = best position(energy) match quality of all 3D clusters sharing a subcluster with the 3D cluster position(energy) match quality keep 3D cluster if: deghostpwr deghostpwr mq_frac + eq_frac >= 1 deghostpwr is a parameter

  5. Plots of mq_frac vs eq_frac for Z->ee monte carlo -red lines represent deghostpwrs of 0.5 and 1 -keep everything above red line -large % of 3D clusters cut, but not many electrons 3D clusters matched to electron all 3D clusters

  6. Effects of deghosting vs pT no deghosting deghostpwr = 0.5 (these plots use 3200 p13.03.00 ttbar monte carlo events)

  7. Effects of deghosting vs isolation ratio of electron matches kept vs. number of other tracks within 8cm deghostpwr = 0.3/no deghosting deghostpwr = 0.5/no deghosting

  8. fakes removed vs isolation deghostpwr = 0.5 deghostpwr = 0.3

  9. Choosing deghostpwr Results for p13.03.00 ttbar MC deghostpwr %3d clusters %matching efficiency of e- removed total >20GeV <20GeV 0.3 21 99.5 100.0 99.1 0.4 47 97.4 99.7 95.9 0.5 62 95.2 99.4 92.6

  10. deghostpwr is the same for mq_frac and eq_frac. Why? - it simplifies things and looks close to optimal plot comparing the best points(o's) in the left plot and the equal deghostpwr(x's) plot made by varying deghostpwr separately for mq_frac and eq_frac

  11. monte carlo real zee candidates

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