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

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? G. Steinbrück 14-Mar-2002

SMT only (Monte Carlo) G. Steinbrück 14-Mar-2002

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 G. Steinbrück 14-Mar-2002

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

Other issues y 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? G. Steinbrück 14-Mar-2002

Other issues y 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? G. Steinbrück 14-Mar-2002

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%) G. Steinbrück 14-Mar-2002

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? G. Steinbrück 14-Mar-2002