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.


http://indico.cern.ch/getFile.py/access?contribId=0&resId=0&materialId=slides&confId=108398

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)


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


Results from Run2010A era

Global muon reconstruction efficienciesBarrelBarrel EndcapsEndcaps



Arbitrated tracker muon id. efficiencies

BarrelBarrel EndcapsEndcaps



Tracker muon LastStationAngTight efficienciesBarrelBarrel EndcapsEndcaps



Tight (VBTF) muon id. efficienciesBarrelBarrel EndcapsEndcaps


Global muon reconstruction efficiencies

Average EffiencyData: 98.8 ± 1.1

%MC: 98.79 ± 0.04

%


%MC: 98.79 ± 0.04

%


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

%



Tight (VBTF) muon id. efficiencies



%MC: 95.99 ± 0.07

%


%MC: 95.99 ± 0.07

%


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


Run2010B vs Run2010A

Global muon reconstruction efficienciesBarrelBarrel EndcapsEndcaps




BarrelBarrel EndcapsEndcaps



Tracker muon LastStationAngTight efficienciesBarrelBarrel EndcapsEndcaps



Tight (VBTF) muon id. efficienciesBarrelBarrel EndcapsEndcaps


Global muon reconstruction efficiencies

Average EffiencyNew: 98.7 ± 1.1

%Old: 98.8 ± 1.1

%


%Old: 98.8 ± 1.1

%








%Old: 100 − 0.1

%


%Old: 100 − 0.1

%



Tight (VBTF) muon id. efficiencies



%Old: 96.3 ± 1.2

%


%Old: 96.3 ± 1.2

%



• 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)


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)

MuBW 28.09.2010 G. Petrucciani (UCSD) 22

Documents

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