UPDATE: Study of Direct Photon at CMSindiacms/indiacms-meetings/august... · QCD-10-019:...

India CMS Mee+ng, BARC, Mumbai03/08/12 -‐ 04/08/12

Sudha Ahuja Brajesh Choudhary

University of Delhi, Delhi, India

Outline Published Results: QCD-‐10-‐019, QCD-‐10-‐035 and QCD-‐10-‐037

‣About QCD-‐10-‐037‣About QCD-‐11-‐005 (ongoing)

• Inputs for the measurement• Efficiency Study• Purity esOmaOon• Unfolding• Comparison with theoreOcal predicOons.

Summary & Plans1

UPDATE: Study of Direct Photons at CMS

03/08/12 -‐ 04/08/12 India CMS Mee+ng, BARC, Mumbai

QCD-‐10-‐019First publicaOon with photons21 < ETγ < 300 GeV & |ηγ| < 1.45. Measurement using cluster shape of the photon.Phys. Rev. Le^. 106, 082001 (2011)

2

Inclusive Photon Measurements:

!

Ldt = 2.9pb"1#

!

Ldt = 36pb"1#

QCD-‐10-‐037 (Details in coming slides)Covers 25 < ETγ

< 400 GeV & |ηγ | < 2.5Measurement using Conversion (low ET range) and IsolaOon (high ET range)Phys. Rev. D 84, 052011 (2011)

QCD-‐10-‐035ETγ

1 > 23 GeV & ETγ2 > 20 GeV with ΔR(γ1, γ2) > 0.45

|ηγ1,γ 2| < 2.5 excluding 1.45 < |ηγ1, γ2| < 1.57Signal & background shapes extracted using ECAL isolaOon variable JHEP01 (2012) 133

Diphoton Measurements:

!

Ldt = 36pb"1#

Published Results

QCD-10-019: arXiv:1012.0799 CERN-PH-EP-2010-053 Phys. Rev. Lett. 106 (2011) 082001

First prompt photon measurement from the LHC: dσ/dET for |η|<1.45, ET>21 GeV, 2.9pb-1

EM shower shape used to estimate signal fraction

Comparison to pQCD calculation: JETPHOX (JHEP 0205:028,2002, Phys.Rev. D73:094007,2006, Phys.Rev. D79:114024,2009 )

Differential Cross Sections: γ + XQCD-10-019 and QCD-10-037

C.M. Kuo, V. Chetluru, S.L.Linn, C.Lin, D. d'Enterria, S-S. Yu, S. Ganjour, S. Ahuja, B. Choudhary, S.W. Li, Z.K. Liu, Y.J. Lu, D. Mekterovic, R.S. Lu, V. Gaultney Werner, Y. Kim, Y.J. Lee, C. Jessop, T. Kolberg, N. Marinelli, J. Branson, C. Palmer, M. Pieri, M.Sani, M.Anderson, K. Ocalan, A. Bornheim,M. Gataullin, J. Veverka

http://cms.cern.ch/iCMS/analysisadmin/cadi?ancode=QCD-10-019

3

QCD-10-037: Phys. Rev. D 84, 052011 (2011) R. Tenchini: ‘our record in speed for PRD’ https://twiki.cern.ch/twiki/bin/view/CMSPublic/PhysicsResultsQCD10037

Acceptance extended to dσ/dET for |η|<2.5 in 4 bins, 25 GeV<ET<400 GeV, 35.9 pb-1

Differential Cross Sections: γ + XQCD-10-037

Combined photon Isolation and Converted photon E/p used to estimate signal fraction

Comparison to pQCD calculation: JETPHOX (JHEP 0205:028,2002, Phys.Rev. D73:094007,2006, Phys.Rev. D79:114024,2009 )

C.M. Kuo, V. Chetluru, S.L.Linn, C.Lin, D. d'Enterria, S-S. Yu, S. Ganjour, S. Ahuja, B. Choudhary, S.W. Li, Z.K. Liu, Y.J. Lu, D. Mekterovic, R.S. Lu, V. Gaultney Werner, Y. Kim, Y.J. Lee, C. Jessop, T. Kolberg, N. Marinelli, J. Branson, C. Palmer, M. Pieri, M.Sani, M.Anderson, K. Ocalan,A. Bornheim,M. Gataullin, J. Veverka

https://twiki.cern.ch/twiki/bin/view/CMSPublic/




QCD-10-035: Answers to CWR comments prepared, ready for discussion with ARC

dσ/dQ for Q={mγγ, ptγγ, Δφγγ, cosθ*}, ET >{20, 23 GeV}, |η|<1.44 and |η|<2.5, ΔR(γγ)>0.45, 36pb-1

ECAL isolation variable used to estimate signal fraction

Compared to pQCD predictions to order αsα2: DIPHOX (Binoth, Guillet, Pilon, Werlen) with gamma2MC (Bern,Dixon, Schmidt)

Differential Cross Sections: γγ + XQCD-10-035

S. Ahuja, O. Bondu, H. Brun, N.Chanon, G. Chen, B. Choudhary, M. Dejardin, D. D’Enterria, J. Fan, F. Ferri, S. Gascon-Shotkin, P. Gras, M. Lethuillier, J. Malcles, L. Millischer, J. Tao, H. Xiao


QCD-‐10-‐019• Studied the MC efficiencies for the analysis:

using the loose and the Oght photon ID cuts for the various templates used in the analysis (given below)

๏ Efficiency for Reco Photon matched with a Generated Photon & with GenIso < 5 GeV + ๏ hadronic/EM fracOon < 0.05 && < 0.01 (barrel) OR ESRaOo > 0.1 (endcaps)๏ hadronic/EM fracOon < 0.05 && combined IsolaOon < 5.0 GeV ๏ hadronic/EM fracOon < 0.05 && Track IsolaOon < (2.0 + 0.001* PTγ) GeV && Ecal IsolaOon<

(4.2 + 0.003* PTγ) GeV && Hcal IsolaOon < (2.2 + 0.001* PTγ) GeV

6

QCD-‐10-‐035• Studied the theoreOcal predicOons using Sherpa

• Requirements on photon

ContribuOons

๏ Number of γ ≥ 2 ๏ PTγ

1 > 21 GeV

๏ PTγ2 > 20 GeV

๏ |ηγ1 , γ2| < 2.5

๏ Exclude 1.442 < |ηγ1 , γ2| < 1.556๏ Generator level Iso (γ1) < 5 GeV๏ Generator level Iso (γ2) < 5 GeV๏ ΔR (γ1 & γ2) ≥ 0.45

!

"i#i#

03/08/12 -‐ 04/08/12 India CMS Mee+ng, BARC, Mumbai 7

• Second measurement on inclusive photons in CMS (using full 2010 dataset)

• Covers range 25 < ETγ < 400 GeV & extended up to endcaps: |ηγ | < 2.5

• Measurement divided in 4 photon pseudo-‐rapidity ranges (differenOal) 0.0 < |ηγ | < 0.9 , 0.9 < |ηγ | < 1.44 , 1.57 < |ηγ | 2.1 & 2.1 < |ηγ | < 2.5

• Measurement using Conversion method for low ET range / IsolaOon for high ET range

• Signal and Background discriminaOng variables:

Conversion Method: ET/pT (energy in ECAL / transverse momentum of e+e-‐ pair in tracker)

IsolaOon Method: Iso = IsoTRK + IsoECAL +IsoHCAL

• Weighted average of differenOal cross secOon measured with the two methods reported

• DifferenOal cross secOon is given as:

where-‐ Nγ – signal photon yield-‐ U – bin by bin unfolding correcOons-‐ L – integrated luminosity-‐ ε – product of reco, ID & trigger efficiencies -‐ ΔΕΤγ – ETγ bin; Δηγ – ηγ bin

QCD-‐10-‐037 (I)

!

Ldt = 36pb"1#

Tes

T


• Photon ID requirements:

• ContribuOon: HLT matching criterion studies using the ΔR(HLT object,γ) and ΔET(HLT object,γ)/ET variables. Trigger efficiency studies using the raOos of independent trigger paths. Documented in AN-‐10-‐458: “Photon Plus Jet: Single Photon HLT path efficiency measurements

for the 2010 dataset”. Analysis with 2010 data

QCD-‐10-‐037 (II)

T/pTE

0 0.5 1 1.5 2 2.5 3

Events/0.097

0

100

200

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400

500

T/pTE

0 0.5 1 1.5 2 2.5 3

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Data

Fitted bkg.

Fit result

| < 0.9!| < 30 GeVT25 < E

-1 = 2.4 pbintL = 7 TeVsCMS (a)

ISO [GeV]0 5 10 15 20

Even

ts / 0

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V

0

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1

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310!

DataFit to dataSignalBackground

(a) = 7TeVsCMS

<100 GeVT80 <E|<0.9 ", |-1 = 36 pbintL

candidate)! R(HLT object,"0 1 2 3 4 5 6 7 8 9

-610

-510

-410

-310

-210

-110

1 HLT_Photon20_Cleaned_L1RHLT_Photon30_Cleaned_L1RHLT_Photon50_Cleaned_L1R_v1HLT_Photon70_Cleaned_L1R_v1

s = 7 TeV#

candidates : All!

-1 candidate!

T/pHLT object

Tp

-1 0 1 2 3 4 5 6 7

-510

-410

-310

-210

-110

1 HLT_Photon20_Cleaned_L1RHLT_Photon30_Cleaned_L1RHLT_Photon50_Cleaned_L1R_v1HLT_Photon70_Cleaned_L1R_v1

s = 7 TeV"

candidates : All!

[GeV]T

p45 50 55 60 65 70 75 80 85 90 95

Effi

cien

cy

0

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1.6HLT_Photon50_Cleaned_L1R_v1HLT_Photon70_Cleaned_L1R_v1

IsoCuts I

s = 7 TeV!

CMS Preliminary|<1.444"|


QCD-‐10-‐037 (III)

[GeV]TE30 40 50 210 210!2

[nb/

GeV]

"d T/d

E#2 d

-510

-210

10

410

710810 + X $ %p + p

JETPHOX)6| < 2.5 ( X 10"2.1 < |

)4| < 2.1 ( X 10"1.57 < |)2| < 1.44 ( X 10"0.9 < |

| < 0.9"|

NLO pQCD JETPHOX

T=ERµ=

fµ=

FµCT10 / BFG II,

MPI and hadronization corrected

< 5 GeVisoT

, E-1 = 36 pbintL = 7 TeVsCMS

[GeV]TE30 40 210 210!2

Data

/The

ory

0.0

0.5

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Data / JETPHOX CT10Stat. + syst. uncertaintyScale uncertainty

uncertaintys" #CT10 PDF

-1 = 36 pbint = 7 TeV, LsCMS (a) < 5 GeViso

T| < 0.9, E$|

[GeV]TE30 40 210 210!2

Data

/The

ory

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T| < 1.44, E$0.9 < |

[GeV]TE30 40 210 210!2

Data

/The

ory

0.0

0.5

1.0

1.5

2.0



-1 = 36 pbint = 7 TeV, LsCMS (c) < 5 GeViso

T| < 2.1, E$1.57 < |

[GeV]TE30 40 210 210!2

Data

/The

ory

0.0

0.5

1.0

1.5

2.0



-1 = 36 pbint = 7 TeV, LsCMS (d) < 5 GeViso

T| < 2.5, E$2.1 < |

Ratios of the measured isolated prompt photon differentialcross section to the NLO pQCD predictions

Predictions from the NLO pQCD calculations are consistent with the measured cross sections within uncertainities. The measurement establishes a benchmark for photon identification & background estimation.It determines the rate of one of the background processes affecting new physics.


h@ps://twiki.cern.ch/twiki/bin/view/CMS/QCDGammaPlusJetQCD11005

10

Vasundhara Chetluru, Brajesh Choudhary, A. Murat Guler, Bob Hirosky, Chuanzhe Lin, Darko Mekterovic, Kadir Ocalan, Sudha Ahuja

Validate perturbative QCD.

Constrain PDFs of the proton.

Reducible background to H → γγ.

Background for many new physics searches such as SUSY, extra dimensions, quark compositeness…

Serves as a reference to similar measurements in heavy ion collisions.

QCD-‐11-‐005: “Measurement for the Triple-differential-cross-section for γ + Jets”

https://twiki.cern.ch/twiki/bin/view/CMS/QCDGammaPlusJetQCD11005

https://twiki.cern.ch/twiki/bin/view/CMS/QCDGammaPlusJetQCD11005


• Measurement of triple-‐differenOal-‐cross-‐secOon for events with at least a photon & a jet in various ETγ , ηγ & ηJet bins

• Binnings: ETγ (GeV): 40-‐45, 45-‐50, 50-‐60, 60-‐70, 70-‐85, 85-‐100, 100-‐145, 145-‐300

|ηγ |: 0-‐0.9, 0.9-‐1.4442, 1.566-‐2.1, 2.1-‐2.5 |ηJet|: 0-‐1.5, 1.5-‐2.5

• Analysis: Efficiency measurement, Purity esOmaOon, Unfolding & Comparison with theoreOcal predicOons.

• Comparison with theory: JETPHOX, SHERPA & PYTHIA • Triple-‐differenOal-‐cross-‐secOon calculated using:

11

!

Ldt = 2.19 fb"1#

where,

!

d3"# ,isolateddET

# d$#d$Jet =1

%ET# %$#%$Jet U

NYield#

L *&

QCD-‐11-‐005: “Measurement for the Triple-differential-cross-section for γ + Jets”


MC Samples Used: (complete list in Back-‐up)‣ PYTHIA Summer11 γ + Jet Z2 tune‣ PYTHIA Summer11 QCD di-‐jet Z2 tune‣ Madgraph γ + Jet

Datasets Run rangeRecorded Luminosity

(pb-‐1)

/Photon/Run2011A-‐May10ReReco-‐v1/AOD 160431-‐163869 216.204

/Photon/Run2011A-‐PromptReco-‐v4/AOD 165088-‐167913 934.059

/Photon/Run2011A-‐05Aug2011-‐v1/AOD 170722-‐172619 373.349

/Photon/Run2011A-‐PromptReco-‐v6/AOD 172620-‐173692 667.180

2011 Datasets used:

Corresponding JSON files used:May10ReReco-‐v1 -‐ Cert_160404-‐163869_7TeV_May10ReReco_Collisions11_JSON_v3.txt

PromptReco-‐v4 & v6 -‐ Cert_160404-‐177053_7TeV_PromptReco_Collisions11_JSON.txt

05Aug2011-‐v1 -‐ Cert_170249-‐172619_7TeV_ReReco5Aug_Collisions11_JSON_v2.txt

12

INPUTS for the Measurement (I)


Trigger Paths Used:

HLT trigger path Run rangeRecorded

Luminosity (Eff.)(pb-‐1)

EventspT range (GeV)

HLT_Photon30_CaloIdVL_v1-‐7 160431-‐173692 2190.8 (3.53) 1208139 40-‐60

HLT_Photon30_CaloIdVL_v1-‐3HLT_Photon50_CaloIdVL_v1-‐4

160431-‐165087165088-‐173692 2190.8 (11.67) 1231920 60-‐85

HLT_Photon75_CaloIdVL_v1-‐7 160431-‐173692 2190.8 (276.93) 1756132 85-‐100

HLT_Photon75_CaloIdVL_v1-‐3 HLT_Photon90_CaloIdVL_v1-‐4

160431-‐165087165088-‐173692 2190.8 (361.80) 1844488 100-‐145

HLT_Photon75_CaloIdVL_v1-‐3HLT_Photon125_v1-‐2HLT_Photon135_v1-‐2

160431-‐165087165088-‐166967167039-‐173692

2190.8 (2190.6) 1220065 145-‐300

13

INPUTS for the Measurement (II)


Physics Objects Used:

‣ Photon -‐ reco photons

‣ Photon ID Cuts: • hadronic/EM fraction (H/E < 0.05)

• Shower shape (Barrel) ( < 0.010)

• Shower shape (Endcaps) ( < 0.028)

• No pixel seed required

‣ Jet -‐ AK5 pfJets

‣ Jet ID Cuts: • Neutral hadron frac+on < 0.99

• Neutral EM frac+on < 0.99

• Number of Cons+tuents > 1

• For η < 2.4 and η > -‐2.4,

• Charged hadron frac+on > 0

• Charged mul+plicity > 0

• Charged EM frac+on < 0.99

• Residual jet energy correc+ons applied

• ΔR(γ,Jet) > 0.50

!

"i#i#

!

"i#i#

14

INPUTS for the Measurement (III)

‣ Side band SelecOon Cuts: • hadronic/EM fraction (H/E < 0.05)

• Shower shape (Barrel) (0.011 < < 0.015)

• Shower shape (Endcaps) (0.035 < < 0.040)

• No pixel seed required

!

"i#i#

!

"i#i#


‣ HLT Efficiency (εTrigger): ๏ Data driven, using Tag & Probe

๏ Tag -‐ Electron passing VBTF WP80 ID, PT > 20 GeV, passing single/double electron trigger

๏ Probe -‐ Electron passing offline photon ID, PT > 20 GeV, passing single photon HLT

๏ Pair selec+on -‐ exclude transi+on gap and consider mass window 60 GeV < MZ < 120 GeV.

๏ RaOo technique -‐ using ra+o of independent prescaled trigger paths.

‣ ReconstrucOon efficiency (εRECO):๏ Using simulaOon (PYTHIA)

๏ Eff = Generated Photons matched to a Reconstructed Photon

๏ Generator level isola+on < 5.0 GeV

๏ Efficiency almost 98 -‐ 99 %

) (GeV/c)!(T

p50 60 70 80 90 100 110 120 130 140

Eff

icie

ncy

0

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1

1.2

)"!(T

A RooPlot of "pCMS Preliminary 2011 = 7 TeVs

-1L dt= 216 pb"HLT_Photon75_CaloIdVL

(GeV/c)T

GEN Photon p50 100 150 200 250 300

RE

CO

Eff

icie

nc

y

0.80

0.85

0.90

0.95

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)|<1.4442!("0.9 < |

)|<2.1!("1.566<|

)|<2.5!("2.1<|

CMS = 7 TeVs

15

All Generated Photons

[GeV]T

p55 60 65 70 75 80 85 90 95 100

Eff

icie

nc

y

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HLT_Photon50_CaloIdVLHLT_Photon75_CaloIdVL

s = 7 TeV!CMS

Efficiency Measurement (ε = εTrigger×εRECO×εID×εPMV) (I)


‣ ID Efficiency (εID): (photon ID as given on slide 8)๏ Using both data and simulaOon

๏ Eff = Reconstructed Photons passing photon ID

๏ Difference in MC and data is reported as systema+c uncertainity

‣ Pixel Match Veto Efficiency (εPMV):๏ Inherited from a previous analysis (CMS AN-‐2012-‐043)

๏ Probability for a reconstructed signal photon not to match any reconstructed track in the pixel detector that is consistent with a primary vertex

(GeV/c)T

RECO Photon p50 100 150 200 250 300

ID E

ffic

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y

0.75

0.80

0.85

0.90

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CMS = 7 TeVs

16

All Reconstructed Photons

Efficiency Measurement (ε = εTrigger×εRECO×εID×εPMV) (II)


• IsolaOon Template Used for the measurement:

‣ IsolaOon = (Tracker + ECAL + HCAL) isolaOon

• Signal Template -‐ Obtained from PYTHIA γ+jet MC using Gaussian convoluted with lifeOme funcOon

• Background Template -‐ Obtained from DATA sideband selecOon using inverted ARGUS funcOon

• Signal + Background Template -‐ fit to DATA template w i t h S u m ( I s o ) = N S S ( I s o ) + N B B ( I s o ) [NS -‐ esOmated # of signal events & NB -‐ esOmated # of background events]

• Pile-‐Up reweighOng: Reweight # of pileup interacOon from the simulaOon truth to the target pileup distribuOon for data

17

Purity EsOmaOon (I)

!""#

$#

%&'&#

()*+&,#

-&./*012+3#

Isolation (GeV)0 5 10 15 20 25 30

Even

ts /

( 0.5

)0

500

1000

1500

2000

2500

3000

3500CMS 2011

= 7 TeVs < 100 GeVT

!85 GeV < E| < 0.9000!"0.0000 < |

| < 1.5jet"0.0 < |

Data

Signal Component

Background Component

Fitting Result


• SystemaOcs (All uncertainiOes added in quadrature)‣ Uncertainity on Signal Template from γ+jet MC:

Study signal template of photon objects between Z→μμγ MC and Data events. Fit results from MC and data using the signal template fi�ng funcOon match very well. Difference in value of purity obtained by varying fi�ng parameter up & down is quoted as uncertainity.

‣ Uncertainity on Background Template: Uncertainity due to mis-‐match between sideband and signal like selecOon in QCD events, evaluated using pseudo experiment.

18

Purity EsOmaOon (II)

(GeV)T

p!50 100 150 200 250 300

Pur

ity

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1 CMS 2011 preliminary = 7 TeVs

| < 0.9!"0 < |

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(GeV)T

p!50 100 150 200 250 300

Pur

ity

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ity

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Pur

ity

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| < 2.5!"2.1 < |

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Purity results


• For every differenOal measurement a mapping between measured and true values of the variables has to be evaluated

• In our case 3D unfolding (black: bins used for measurement; red: addiOonal bins used for unfolding):

PTγ : 30-‐40, 40-‐45, 45-‐50, 50-‐60, 60-‐70, 70-‐85, 85-‐100, 100-‐145, 145-‐300, 300-‐500 GeV

|ηγ |: 0-‐0.9, 0.9-‐1.4442, 1.4442-‐1.566, 1.566-‐2.1, 2.1-‐2.5, 2.5-‐2.6

|ηJet|: 0-‐1.5, 1.5-‐2.5, 2.5-‐2.7

• IteraOve (Bayesian) method is employed

• Result consistent with results from bin by bin correcOon method

• UncertainiOes:

“StaOsOcal”, due to the limited size of MC samples

Due to the difference in shape between data and MC distribuOons

Due to the difference in efficiency between data and MC

19

UNFOLDING


๏ JETPHOX

• Program to calculate the reacOons hadron hadron → gamma/hadron + jet + X.• Evaluates cross secOon at NLO accuracy

๏ SHERPA: “SimulaOon of High Energy ReacOons of ParOcles”.

‣ Leading order 2→n hard process generator.

‣ Inbuilt matrix-‐element generators: Comix -‐ default large mulOplicity matrix element generator.

‣ Provides completely unweighted, inclusive and fully hadronized final states.

‣ Main feature’s of Sherpa:

• Provides a be^er descripOon of mulOjets processes.

• Similar technique also extended to the processes involving hard photons. “DemocraOc” extension of QCD ME+PS merging to QED. (Reference -‐ S. Hoche and S. Schumann and F. Siegert, Hard photon producOon and matrix-‐element parton-‐shower merging, Phys. Rev. D81 (2010) 034026 [arXiv:0912.3501]).

• Provides an improved descripOon of Tevatron direct photon measurements.

TheoreOcal PredicOons: JETPHOX/ SHERPA


• Studied the following sources of uncertainiOes:

‣ Scale uncertainiOes

• varied the default values of renormalizaOon(μR) & factorizaOon(μF) scales in range around [1/2,2]

๏ μR = 1/2μR & μF = μF; μR = 1/2μR & μF = 2μF;

๏ μR = μR & μF = 1/2μF; μR = μR & μF = 2μF;

๏ μR = 2μR & μF = μF; μR = 2μR & μF = 1/2μF;

‣ PDF uncertainiOes

• varied PDF sets from the default PDF set

• uncertainity from within error sets in a single PDF

21

SystemaOcs for TheoreOcal predicOons


Results are compared to JETPHOX and SHERPA.

Results are binned in the four photon pseudorapidity regions and two jet pseudorapidity regions under study.

22

Triple-‐differenOal-‐cross-‐secOon (DATA/ SHERPA/ JETPHOX)

‣ Values from Jetphox and Sherpa are close enough. ‣ In low PTγ bins there is dis-‐agreement between the Data and predicOons.

‣ In some high PTγ bins in Endcaps, Sherpa is closer to Data than Jetphox.

(GeV)!

Tp

40 50 60 70 80 210 210"2 210"3

jet

#d! #d! T/d

p$3 d

-210

-110

1

10

210

310

410

510

610

710

810

910

| < 1.5jet#|

CMS Preliminary s = 7 TeV%

JETPHOXSHERPA

| < 0.9!#|)2| < 1.4442 (X10!#0.9 < |

)4| < 2.1 (X10!#1.566 < |)6| < 2.5 (X10!#2.1 < |

(GeV)!

Tp

40 50 60 70 80 210 210"2 210"3

jet

#d! #d! T/d

p$3 d

-310

-210

-110

1

10

210

310

410

510

610

710

810

910

| < 2.5jet#1.5 < |

CMS Preliminary s = 7 TeV%

JETPHOXSHERPA

| < 0.9!#|)2| < 1.4442 (X10!#0.9 < |

)4| < 2.1 (X10!#1.566 < |)6| < 2.5 (X10!#2.1 < |

ObservaOons:


RaOos of Triple-‐differenOal-‐cross-‐secOon (DATA/ SHERPA)

Sherpa follows similar pa^ern as Data in most of the regions.


• “Inclusive photon” (QCD-‐10-‐019 & QCD-‐10-‐037) and “Diphoton” (QCD-‐10-‐035)analysis published in CMS upto now. (Significant contribu.on in QCD-‐10-‐037)

• The current ongoing analysis is QCD-‐11-‐005, “Measurement of the γ+jet events” with 2.19 �-‐1 of data.

• QCD-‐11-‐005 is currently pre-‐approved inside the SMP group and is in compleOon stage of the ARC reviewal process. It will be going for approval soon when ARC gives the green light.

• Plan to complete the reviewal process of QCD-‐11-‐005 and get it approved.• Thesis Structure: Plan a thesis based on QCD-‐10-‐037 (Inclusive Photon

measurement) and QCD-‐11-‐005 (γ + Jets measurement).

24

STATUS & PLANS


• Shi�s: (January-‐June) Took 4 weeks of shi�s as ECAL PFG expert

• Online Z peak calibraOon perform an offline study on electron/photon enriched datasets a�er applying the eID cuts

resolve the Z peak offline using ECAL informaOon only

check the feasibility of the study -‐ Enough staOsOcs to resolve Z peak

calibrate the Z peak in the online DQM with similar set of ECAL only cuts available online

Also check for similar study with other parOcles -‐ π0 and J/ψ

• Status: (January-‐June) Feasibility and offline study ongoing

Move to online study and calibrate the Z peak

25

Service Work


Back-‐UP


Data/Theory with uncertainiOes

(GeV)!

Tp

40 50 60 70 80 90 210 210"2 210"3

data

/theo

ry

0

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0.8

1

1.2

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1.6

1.8

2

| < 2.5jet#1.5 < | | < 1.44!#0.9 < |

CMS Preliminary s = 7 TeV$

JETPHOX scale variation

JETPHOX PDF variation

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| < 1.5jet#| | < 1.44!#0.9 < |




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ry

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| < 2.5jet#1.5 < | | < 0.9!#|




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| < 1.5jet#| | < 0.9!#|





Data/Theory with uncertainiOes

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data

/theo

ry

0

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| < 2.5jet#1.5 < | | < 2.5!#2.1 < |




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Tp

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data

/theo

ry

0

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| < 1.5jet#| | < 2.5!#2.1 < |




(GeV)!

Tp

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data

/theo

ry

0

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| < 2.5jet#1.5 < | | < 2.1!#1.57 < |




(GeV)!

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data

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ry

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| < 1.5jet#| | < 2.1!#1.57 < |





List of MC Datasets


jet in Barrel, opposite η side

jet in Endcap, opposite η sidejet in Endcap, same η side

γ

jet in Barrel, same η side

Tracker

ECALHCAL

|ηjet|<1.45, ηjetηγ>0 |ηjet|<1.45, ηjetηγ<0

1.55<|ηjet|<2.4, ηjetηγ >0 1.55<|ηjet|<2.4, ηjetηγ <0

γ

γ γ

• Different γ+jet orienta+ons (Similar orienta+ons used in D0 study)• Photon required to be in barrel

• Lead jet may be central or forward, and may same sign or opposite sign η to photon

DiagrammaOc View of the OrientaOons considered in raOos


Efficiency Back up

03/08/12 -‐ 04/08/12 India CMS Mee+ng, BARC, Mumbai32

PileUp ReweighOng

UPDATE: Study of Direct Photon at CMSindiacms/indiacms-meetings/august... · QCD-10-019:...

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