Bad News from Cracks

1
(Bad) News from Cracks
Robert Zitoun Stony Brook and LAPP CAT Force
Meeting May 27, 2003
2
New Track Matching

• Rewrite track matching code to allow for better
  resolution
• h modulation 5 mm. Period 0.05 (EM3 period)
• j modulation 5 mm. Period 0.2 (crack period)
• Note extrapolation made with ET.Have to correct
  ET in the crack torecover same field integral

3
How wide is the crack

• Crack with calo position(standard)
• Correct calo position
• Extrapolate tracks and plot track j (mod
  0.2)Loss smaller than previously thought
• Moreover analyzed clusters are matched
• by present tracking (might be even better)

cluster angle
corrected cluster angle
track angle
4
Energy Loss in the Crack

• Oleg gauss(20, s 15mrad)
• Best (mass) gauss(21, s 16mrad)
• mine gauss(20, s 7mrad)

cluster angle
corrected cluster angle
track angle
5
Detailed Crack Study

• Shower shape affected by crack
• Correct cell with gauss(20, 8 mrad)

6
Energy correction in the crack

• Brute or cell correction equivalent
• Not perfect
• No effect above 0.02 mrad
• (even in not corrected angle)

track angle
cluster angle
7
Z mass

• p13.05 p13.06 r13.06 (jonas)
• certified matched
• still 1.7 GeV mass differenceclose/far crack
• not the crack itself? statistics?

cracklt0.05 89.6 GeV 3.60.2