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

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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 &gt; 25 GeV

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### 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

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)

v94: q*dM/MzID parameters

small

ID mis alignments

ID parameters v94

Yellow band dpT/pT = +- 0.20 (pT/TeV)

v94: q*dM/MzCB parameters

Phi modulation due to ID-MS mis alignment

Better than Tier0 processing

CB parameters v94

Yellow band dpT/pT = +- 0.20 (pT/TeV)

v94: q*dM/MzSA parameters

Compare to next slide

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

### 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

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)

v93: q*dM/MzID parameters

small

ID mis alignments

ID parameters v93

Yellow band dpT/pT = +- 0.20 (pT/TeV)

v93: q*dM/MzCB parameters

Phi modulation due to ID-MS mis alignment

Similar to Tier0 processing

CB parameters v93

Yellow band dpT/pT = +- 0.20 (pT/TeV)

v93: q*dM/MzSA parameters

Compare to next slide

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