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

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

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

6. 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

7. 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

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%)
G. Steinbrück
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 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