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Electron tagging possibilities with current data

Electron tagging possibilities with current data. Georg Steinbr ü ck B id meeting. Tracks. Reminder: tagging b jets with electrons relies on projecting tracks into the calorimeter and looking at calorimeter cells around the track: Road Method

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Electron tagging possibilities with current data

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  1. Electron tagging possibilities with current data Georg Steinbrück B id meeting 14-Mar-2002

  2. Tracks • Reminder: tagging b jets with electrons relies on projecting tracks into the calorimeter and looking at calorimeter cells around the track: Road Method • Question: How well can we do with the current state of the detector and tracking • Specially: CFT axial only trackingh has to come from SMT • ptrel calculated from track momentum: Momentum resolution of these tracks? 14-Mar-2002

  3. SMT only (Monte Carlo) 14-Mar-2002

  4. SMT->CFT axial (Monte Carlo) • (h) = 0.003 s (Q)=0.003 • (z) = 2.7 mm s(f) = 0.003s(rf)=2.7 mm EM Cell size= 0.05x0.05 in (h,f) dz(Cell) = 4.6 cm at EM3 (91cm) and h = 0 d(rf) (Cell) = 4.6 cm Pointing well within a EM cell 14-Mar-2002

  5. Default global tracks (Monte Carlo) 14-Mar-2002

  6. y Other issues • SMT alignment 20-30 mm • ½ of SMT is shifted by 1mm • Shift of tracker wrt calorimeter: 2.9 cm in z • The last shift is comparable to the cell size and should/has to be dealt with. • Otherwise: Lower efficiencies • Calorimeter Cells in root tupleCould develop road method running at the root level: Might be hard. • rereco with that shift taken into account: p11 • Port into private version of p10? 14-Mar-2002

  7. y Other issues • Chpart_reco uses 401 tracks • in p10, 401 tracks choose best chi sq tracks: CFT only preferred over 11 hit tracks • Fixed in p11 until then: use 333 (SMTCFT) • Could rerun (private version of) chpart_reco in p10 with 333 tracks? 14-Mar-2002

  8. Momentum resolution • ptrel depends on px, py, pz of track. • E/p: Ia’s studies under way. Results encouraging • Avto’s studies look very encouraging: • J/Psi Mass resolution 50 MeV (pt>3 GeV) • Fake rates a few % (SMT only ~50%) 14-Mar-2002

  9. y Conclusion • Monte Carlo studies of angular resolutions suggest that the road method should perform well with SMTCFT (axial) tracks • Momentum resolution (important for ptrel) being studied: Probably ok • Might need to rereco p10 files because of z shift and 401 problem • electron tagging should be feasible with current data in p11: 401 tracks include 333 + 2.8 cm z shift taken into account • Started to look into p10 data: Should one try to make a private version of p10 with fixes? 14-Mar-2002

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