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Momentum scale in the 2012 data in v94: improved MS alignment

Momentum scale in the 2012 data in v94: improved MS alignment. Niels van Eldik, Peter Kluit, Alan Poppleton MCP/MATF meeting 1November 10 October / 20 May 2012. Introduction. Use Z skimmed data periods 2012 v94: Currently used at Tier 0 Standard selection of two CB muons pT > 25 GeV

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Momentum scale in the 2012 data in v94: improved MS alignment

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  1. Momentum scale in the 2012 datain v94: improved MS alignment Niels van Eldik, Peter Kluit, Alan Poppleton MCP/MATF meeting 1November 10 October / 20 May 2012

  2. Introduction Use Z skimmed data periods 2012 v94: Currently used at Tier 0 Standard selection of two CB muons pT > 25 GeV Basic idea: use the Z mass as probe Mass = (Combined parameters, SA parameters) and vice versa Plot dM/Mz = (Mass(eta SA, phi sector MS)-Mz)/Mz dM/Mz -> observe B field effects q*dM/Mz -> sensitive to MS calibration and alignment Extrapolate the q dM/M number to 1 TeV from pT = 40 GeV. So express systematic curvature offset as alpha (typically 0.10): dpT/pT = alpha pT TeV-1 @ 1 TeV Use therefore a factor 2*1000/40 = 50 to go from dM/M to alpha. Reason for factor 2: 2*dM/M = dp/p (M2 = p1*p2 etc)

  3. v94: q*dM/MzID parameters small ID mis alignments

  4. ID parameters v94 Yellow band dpT/pT = +- 0.20 (pT/TeV)

  5. v94: q*dM/MzCB parameters Phi modulation due to ID-MS mis alignment Better than Tier0 processing

  6. CB parameters v94 Yellow band dpT/pT = +- 0.20 (pT/TeV)

  7. v94: q*dM/MzSA parameters Compare to next slide

  8. SA parameters v94

  9. v94: q*dM/MzSA best parameters • Best selection: • No BEE/EEL/EES • - 3 stations • 2 phi layers • no Barrel-Endcap

  10. SA best parameters v94

  11. v94: no q dM/MzID parameters

  12. v94: no q dM/MzCB parameters

  13. Conclusions Relevant for the Higgs are the CB and ID momentum resolutions Observe some misalignments in ID in endcaps both all smaller than dpT/pT < 20% @ 1 TeV Some structure in the CB in the endcap (eta >0). Similar to structure observed in Tier0 processing. Maximally dpT/pT ~20% @ 1 TeV. Note that the structure in the mass (slides 11-12) is much smaller (due to cancellation of + and – charges). Likely cause of structure in (positive eta) endcap is ID-MS misalignment. Means that v94 is better for MS alignment. However, an additional ID-MS alignment is needed to reduce the momentum bias of less than ~20% @ 1 TeV.

  14. Momentum scale in the 2012 datain v93: improved MS alignment Niels van Eldik, Peter Kluit, Alan Poppleton MCP/MATF meeting 1November 10 October / 20 May 2012

  15. Introduction Use Z skimmed data periods 2012 v93 Standard selection of two CB muons pT > 25 GeV Basic idea: use the Z mass as probe Mass = (Combined parameters, SA parameters) and vice versa Plot dM/Mz = (Mass(eta SA, phi sector MS)-Mz)/Mz dM/Mz -> observe B field effects q*dM/Mz -> sensitive to MS calibration and alignment Extrapolate the q dM/M number to 1 TeV from pT = 40 GeV. So express systematic curvature offset as alpha (typically 0.10): dpT/pT = alpha pT TeV-1 @ 1 TeV Use therefore a factor 2*1000/40 = 50 to go from dM/M to alpha. Reason for factor 2: 2*dM/M = dp/p (M2 = p1*p2 etc)

  16. v93: q*dM/MzID parameters small ID mis alignments

  17. ID parameters v93 Yellow band dpT/pT = +- 0.20 (pT/TeV)

  18. v93: q*dM/MzCB parameters Phi modulation due to ID-MS mis alignment Similar to Tier0 processing

  19. CB parameters v93 Yellow band dpT/pT = +- 0.20 (pT/TeV)

  20. v93: q*dM/MzSA parameters Compare to next slide

  21. SA parameters v93

  22. v93: q*dM/MzSA best parameters • Best selection: • No BEE/EEL/EES • - 3 stations • 2 phi layers • no Barrel-Endcap

  23. SA best parameters v93

  24. v93: no q dM/MzID parameters

  25. v93: no q dM/MzCB parameters

  26. Conclusions Relevant for the Higgs are the CB and ID momentum resolutions Observe some misalignments in ID in endcaps both all smaller than dpT/pT < 20% @ 1 TeV Some structure in the CB in the endcap (eta >0). Similar to structure observed in Tier0 processing. Maximally dpT/pT ~20% @ 1 TeV. Note that the structure in the mass (slides 11-12) is much smaller (due to cancellation of + and – charges). Likely cause of structure in (positive eta) endcap is ID-MS misalignment. Means that v93 is better for MS alignment. However, an additional ID-MS alignment is needed to reduce the momentum bias of less than ~20% @ 1 TeV.

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