Muon reco . efficiency status: from J/psi to Z T&P

Muon reco. efficiency status: from J/psi to Z T&P

Giovanni Petrucciani (UCSD)

Outline

• Introduction• Results for the “Run2010A” period

(before the last technical stop; about 3/pb)– Turn on curves from J/Psi– Efficiency on the plateau from Z

• New results for the “Run2010B” period(last week of running; integrated luminosity about 2/pb for Z and 1/pb for J/Psi)

MuBW 28.09.2010 2G. Petrucciani (UCSD)

Introduction

• The Tag & Probe method allows to measure the muon reconstruction efficiencies using di-muons from resonances like J/Psi and Z(see Zoltan’s talk Monday at this workshop)

• In this talk, I will discuss about the offline muon reconstruction and id. efficiencies.

MuBW 28.09.2010 3G. Petrucciani (UCSD)

Reconstruction efficiencies

• The efficiency to reconstruct a muon using also the inner tracker can be parametrized aseff(mu) = eff(inner track) * eff(track -> mu)

• The efficiency to reconstruct the inner track is approx. 100% for all muons from J/Psi and Z, so we will measure only eff(track -> mu)

• The measurement of the standalone reco. efficiency is more complex, as one has to handle the matching. Studies are ongoing (D. Trocino)

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Triggers and selections

• In order to collect (muon + track) pairs in an unbiased way:– For Z, we just require that the muon fires the Mu9

trigger (still unprescaled in the 2E31 menu)– For J/Psi, the situation is more difficult:

At trigger level, use Mu5_Track0_Jpsi triggerAt offline level, require the track to be a calo muon in order to reduce the background from muon + hadron pairs

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Results from Run2010A era

Global muon reconstruction efficienciesBarrelBarrel EndcapsEndcaps

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Results from Run2010A era

Arbitrated tracker muon id. efficiencies

BarrelBarrel EndcapsEndcaps

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Results from Run2010A era

Tracker muon LastStationAngTight efficienciesBarrelBarrel EndcapsEndcaps

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Results from Run2010A era

Tight (VBTF) muon id. efficienciesBarrelBarrel EndcapsEndcaps

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Global muon reconstruction efficiencies

Average EffiencyData: 98.8 ± 1.1

%MC: 98.79 ± 0.04

%

Average EffiencyData: 98.8 ± 1.1

%MC: 98.79 ± 0.04

%

Results from Run2010A era

PT > 20 GeVPT > 20 GeV

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Results from Run2010A era

Arbitrated tracker muon id. efficiencies

PT > 20 GeVPT > 20 GeV

Average EffiencyData: 100.0 − 0.8

%MC: 99.52 ± 0.02

%

Average EffiencyData: 100.0 − 0.8

%MC: 99.52 ± 0.02

%

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Results from Run2010A era

Tight (VBTF) muon id. efficiencies

PT > 20 GeVPT > 20 GeV

Average EffiencyData: 96.3 ± 1.2

%MC: 95.99 ± 0.07

%

Average EffiencyData: 96.3 ± 1.2

%MC: 95.99 ± 0.07

%

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New results from Run2010B era

Disclaimers:• These runs have not yet been certified yet.

What I’ve used is:– DCS status flags of all subdetectors– Manual certification flag for Muon only

(DPG flags were sometimes inconsistent beween between online and offline flags)

• I didn’t process 3.8.X MC yet, so I’ll show only plots of Run2010A data vs Run2010b data

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Run2010B vs Run2010A

Global muon reconstruction efficienciesBarrelBarrel EndcapsEndcaps

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Run2010B vs Run2010A

Arbitrated tracker muon id. efficiencies

BarrelBarrel EndcapsEndcaps

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Run2010B vs Run2010A

Tracker muon LastStationAngTight efficienciesBarrelBarrel EndcapsEndcaps

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Run2010B vs Run2010A

Tight (VBTF) muon id. efficienciesBarrelBarrel EndcapsEndcaps

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Global muon reconstruction efficiencies

Average EffiencyNew: 98.7 ± 1.1

%Old: 98.8 ± 1.1

%

Average EffiencyNew: 98.7 ± 1.1

%Old: 98.8 ± 1.1

%

Run2010B vs Run2010A

PT > 20 GeVPT > 20 GeV

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Run2010B vs Run2010A

Arbitrated tracker muon id. efficiencies

PT > 20 GeVPT > 20 GeV

Average EffiencyNew: 99.8 ± 0.2

%Old: 100 − 0.1

%

Average EffiencyNew: 99.8 ± 0.2

%Old: 100 − 0.1

%

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Run2010B vs Run2010A

Tight (VBTF) muon id. efficiencies

PT > 20 GeVPT > 20 GeV

Average EffiencyNew: 96.3 ± 1.2

%Old: 96.3 ± 1.2

%

Average EffiencyNew: 96.3 ± 1.2

%Old: 96.3 ± 1.2

%

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Run2010B vs Run2010A

• In general, good agreement between Run2010A (3.6.X) and Run2010B (3.8.X).Two visible differences:– Large increase in tracker muon efficiency in the

endcaps for pT = 1-2 GeV (?)

– Improvement in the turn on curve for tight muon efficiency (plateau value on Z unaffected)

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Conclusions

• Muon reconstruction efficiencies have been measured on data using J/Psi and Z.

• At the current luminosities, a few days of data-taking are enough to get good quality measurements of the turn on and plateau.

• In general, there is good agreement between new data (3.8.X), old data (3.6X) and MC.Some differences for soft tracker muons, but in the good direction (3.8.X > 3.6.X > MC)

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