Photon performance with early 7TeV data

1) photon performance (using f249): data/MinBias MC2) comparison: data / MinBias MC / +jets MC

D. Zhang (IPAS&USTC) &

N. Panikashvili (UM)

Data / MC

• Data:– Run: (f249)153134, 153136, 153159,

153200– LHC stable beam– Pixel SCT green– Same lumiblocks as e/ GRL

• MC:– 105001, Pythia_Minbias– reconstruction tag r1210 (using DB

release 9.6.1)

Trigger & PV selection• Trigger: Require data and MC passing L1_MBTS_1_1

(require a 1-hit-coincidence)• Primary vertices: select event with a good primary

vertex which has at least 3 tracks

Data MC

Total N 3.7M 10M

Efficiency trigger 75% 99%

Efficiency PV 95.6% 97.6%

N events 2.6M 9.6M

Object selection electron:

Author 1 or 3 isEM is tight p

T>5GeV, |η|<2.47 and exclude crack region [1.37, 1.52]

N of pixel hits >1, N of SCT hits > 6 muon (Staco):

combined muon p

T> 5GeV, |η|<2.5

N of pixel hits >1, N of SCT hits > 6 photon:

pT(γ) >5GeV, |η|<2.37 and exclude crack region [1.37, 1.52] ΔR > 0.2 between leptons and γ isEM is loose, tight

jet: AntiKt4H1Topo Jet p

T>20GeV, |η|<3.1

remove jets overlapped with tight electron or tight photon in cone 0.4 remove jets: jet N90 ≤ 2 & SamplingMax = 17

Photon cut flow efficiency

SelectionData MC

All Author = 4 Author = 16 All Author = 4 Author = 16

Overlap removal 11356 5901 5455 90653 49797 40856

isEM loose 2499 (22%) 1508 1007 24449 (26%) 15204 9245

isEM tigth 358 (3.1%) 189 169 5042 (5.6%) 2859 2183

isEM tightIso 5 (0.04%) 2 3 87 (0.096%) 52 35

Cut efficiency with respect to previous cut Overall efficiency

photon pT: all, Author = 4, Author = 16

Overlapremoval

isEM - loose

isEM - tight

photon isEM - loose isEM - tight

all

Author = 4

Author = 16

events with loose photonsJet pT Leading jet pT

Jet multiplicity Jet sum ET

events with tight photonsJet pT Leading jet pT

Jet multiplicity Jet sum ET

MET/sumETisEM - loose isEM - tight

events with loose photons

Δφ (leading jet, MET)Δφ(Leading photon, MET)

Meff

events with tight photons

Δφ (leading jet, MET)Δφ(Leading photon, MET)

Meff

• Compare: – Data: integrated luminosity 347.1μb-1 – MinBias MC: (MinBias) = 48445 μb +jets MC: (+jets) = 1.41 μb

• Events requirement:– At least one jet with pT>20GeV

– One loose/tight photon: pT>10GeV, ||<2.3

events with loose/tight and at least one jet

isEM - loose

isEM - tight

events with tight and at least one jetLeading jet pTJet pT

HTMET

events with tight photons and one jetΔφ (leading jet, MET)Δφ(photon, MET)

Δφ(photon, jet)

Conclusions

• Agreement (in shape of the distributions) between Data/MC

• Continue check performance with new runs

• High fake photons rate in the low pT range