1. Z Segmentation Update (improving reconstruction of non- prompt tracks with the SiD) Lori Stevens (SLAC/UCSC) August 21, 2007 ILC Simulation Reconstruction Meeting

2. AxialBarrelTrackFinder1 Bug Phi requirement: phi coordinate of all hits must be within π/2 of each other Bug in my version of code caused phi requirement to be too restrictive Fixed bug and found improvement in both efficiency and number of fake tracks when using z segmentation

3. Comparing Z Segmentation Before and After Fix Sample: pythiaZPolebbbar-0-1000_SLIC_v1r9p3_sidaug05.slcio NoneNone no bug 30cm 30cm30cm no bug 10cm 10cm10cm no bug 5cm5cm 1cm1cm #MCPs304304304304304304304304304304 Found with 5 hits 145155144161157162156157126126 Found with 4 hits 112115110113115115117117106107 Missed47345030322731307271 Fake15865156554817221041

4. Some other studies (collisions at 500GeV) panpyuds_nobeam_nobrem-1-500_SLIC_v2r0p6_sidaug05.slciopanpyuds_nobeam_nobrem-3-500_SLIC_v2r0p6_sidaug05.slciopanpyuds_nobeam_nobrem-7-500_SLIC_v2r0p6_sidaug05.slcio

5. panpyuds_nobeam_nobrem-1- 500_SLIC_v2r0p6_sidaug05.slcio No segments 30cm segments 10cm segments 5cm segments 1cm segments # MCPs 3333333333 Found with 5 hits 1515151614 Found with 4 hits 1311151614 Missed57315 Fake5961373018

6. panpyuds_nobeam_nobrem-3- 500_SLIC_v2r0p6_sidaug05.slcio No segments 30cm segments 10cm segments 5cm segments 1cm segments # MCPs 169169169169169 Found with 5 hits 7984808164 Found with 4 hits 6666697173 Missed2419201732 Fake26225516112852

7. panpyuds_nobeam_nobrem-7- 500_SLIC_v2r0p6_sidaug05.slcio No segments 30cm segments 10cm segments 5cm segments 1cm segments # MCPs 150150150150150 Found with 5 hits 6973737257 Found with 4 hits 4644535456 Missed3433242337 Fake25223915710052

8. Combining the 3 data sets No segments 30cm segments 10cm segments 5cm segments 1cm segments # MCPs 352352352352352 Found with 5 hits 163172168169135 Found with 4 hits 125121137141143 Missed6359474174 Fake573555355258122

9. ZPole vs. 500GeV collisions 1cm5cm10cm30cm 1cm5cm10cm30cm

10. Conclusion The use 4 hit tracks may depend on the jet energy Will 10cm segmentation make a difference? Tyler Rice and Chris Meyer are doing a study using variable segmentation in Dima Onoprienko's Garfield Tracker…this may help find some answers

11. HelicalTrackFitter improvements Does not currently fit hits in tracker barrel Improving to fit hits in all regions Will use various fitting methods such as circle fitting, line fitting, 2D hit consistency checks, and Rich Partridge’s z segmentation code Presentation next Friday (8/31/07)