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# Electron tagging possibilities with current data - PowerPoint PPT Presentation

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

Georg Steinbrück

B id meeting

14-Mar-2002

• 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

14-Mar-2002

• (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

14-Mar-2002

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

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

• 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

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