Electron tagging possibilities with current data

1
Electron tagging possibilities with current data

• Georg Steinbrück
• B id meeting

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?

3
SMT only (Monte Carlo)
4
SMT-gtCFT 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

5
Default global tracks (Monte Carlo)
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?

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?

8
Momentum resolution

• ptrel depends on px, py, pz of track.
• E/p Ias studies under way. Results encouraging
• Avtos studies look very encouraging
• J/Psi Mass resolution 50 MeV (ptgt3 GeV)
• Fake rates a few (SMT only 50)

9
Conclusion

• y

• 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?