1 / 23

Close tracks

Analyzing close track reconstruction in ALEPH experiment by Bolek Pietrzyk and Gerald Rudolph with detailed data-MC comparison and systematic uncertainty assessment.

beverlygomez
Download Presentation

Close tracks

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Close tracks Bolek Pietrzyk LAPP Annecy-le-Vieux Gerald Rudolph Innsbruck Bolek Pietrzyk, Gerald Rudolph close tracks

  2. ALEPH BE results with W-pairs Do we have problem with reconstruction of close tracks in ALEPH? Bolek Pietrzyk, Gerald Rudolph close tracks

  3. Gerald’s tuning at Z Excellent agreement Data – BE MC Presented on November 12th Bolek Pietrzyk, Gerald Rudolph close tracks

  4. Gerald’s tuning Not perfect agreement Data – BE MC Presented on November 12th 0.04<Q<0.2  Bolek Pietrzyk, Gerald Rudolph close tracks

  5. Gerald’s tuning • (pi,pj) in successive 200 MeV • wide intervals up to • 0.8 GeV New Bolek Pietrzyk, Gerald Rudolph close tracks

  6. Comment on angular distribution The 2-particle angle distributions show the small data-MC difference in all 200 MeV Q intervals up to 1 GeV, but the mean is moving up from about 10 degrees to 50 degrees and also the discrepancy is moving to larger angles. So these angles are surely not small, confirming that the small data-MC difference is related to the tuning of the generator and not to the ALEPH apparatus. Next : q and f plots – the same conclusion Bolek Pietrzyk, Gerald Rudolph close tracks

  7. Gerald’s tuning q (pi,pj) in successive 200 MeV wide intervals up to 0.8 GeV New Bolek Pietrzyk, Gerald Rudolph close tracks

  8. Gerald’s tuning f(pi,pj) in successive 200 MeV wide intervals up to 0.8 GeV New Bolek Pietrzyk, Gerald Rudolph close tracks

  9. Systematic uncertainties Re-weighting of pairs in alpha plot could destroy agreement data – BE MC in the Q plot - refit would be necessary. But, let’s take extreme approach and look what is the effect of “correcting” only alpha plot (page 3). The difference data - BE MC is of similar size as the difference between BE and noBE MC. The effect of replacing noBE MC by BE(I) MC was shown at the May 14th, WW meeting (see page 9 and 10 here). With noBE MC “no effect” distribution is shown by the blue points, with BEI MC by the blue line. The difference between data points and blue points on the one hand side and data points and blue line on the other side is practically the same – certainly negligible in comparison with total uncertainty of our results which is 27% for D’ and 35% for Dr’.  double ratio is very robust !!! (see detailed numbers on pages 11,12,13) Bolek Pietrzyk, Gerald Rudolph close tracks

  10. Dr ‘ Divided by standard MC by BEI Bolek Pietrzyk, Gerald Rudolph close tracks

  11. D’ Divided by standard MC by BEI Bolek Pietrzyk, Gerald Rudolph close tracks

  12. Double ratio with MC standard D’ (data,BEB)-BEI Dr’ S2ch = 0-200 MeV, S6ch = 0-600 MeV Bolek Pietrzyk, Gerald Rudolph close tracks

  13. Double ratio with MC BEI D’ (data,BEB)-BEI Dr’ Bolek Pietrzyk, Gerald Rudolph close tracks

  14. Difference MC standard, MC BEI D’ Dr’  close track systematics is below 5% of total uncertainty • Comment from management : • This is valid argument for BEI not for BE between pions • from different Ws. • It is necessary to repeat the analysis with 3 deg. cut between tracks Bolek Pietrzyk, Gerald Rudolph close tracks

  15. Dr ‘ RedHat 7 RedHat 6 Bolek Pietrzyk, Gerald Rudolph close tracks

  16. D’ RedHat 7 RedHat 6 Bolek Pietrzyk, Gerald Rudolph close tracks

  17. Dr ‘ Aachen 2003 3deg. cut Bolek Pietrzyk, Gerald Rudolph close tracks

  18. D’ Aachen 2003 3deg. cut Bolek Pietrzyk, Gerald Rudolph close tracks

  19. Comparison Data-MC with 3 deg. cut Status Aachen 2003 3 deg. cut Bolek Pietrzyk, Gerald Rudolph close tracks

  20. Dr’ Aachen 2003 3 deg. cut -0.124 ± 0.148 ± 0.200 BEB 0.720 ± 0.0553.3s -0.127 ± 0.145 ± 0.200 BEB 0.699 ± 0.0543.3s Bolek Pietrzyk, Gerald Rudolph close tracks

  21. D’ Aachen 2003 3 deg. cut Bolek Pietrzyk, Gerald Rudolph close tracks

  22. D’ fits Aachen 2003 3 deg. cut 2-parameter fit • = -0.001 ± 0.015 ± 0.014 BEB 0.077 ± 0.0063.7s DmW = 9 MeV (LEP 13 MeV) • = -0.002 ± 0.011 ± 0.014 BEB 0.081 ± 0.0044.6s DmW = 7 MeV (LEP 13 MeV) 3-parameter fit 0.0101 ± 0.0047 ± 0.0042 BEB 0.0261 ± 0.0016 1.6s above zero 0.0052 ± 0.0049 ± 0.0042 BEB 0.0311 ± 0.00165s 0.8s above zero Bolek Pietrzyk, Gerald Rudolph close tracks

  23. Conclusions There is no problem with close track simulation for this analysis. Bolek Pietrzyk, Gerald Rudolph close tracks

More Related