JEC performance plots for 2012

Detector performance plot DP-2012/012 .


Figure Caption

Pile-up composition in data. The 'charged pile-up' is PF charged hadrons that are not associated to a primary vertex, and therefore are not removed by the charged hadron subtraction (CHS). Instead, they are handled by pile-up corrections together with neutral contributions.

This plot is produced with the 'Random Cone' method by taking pile-up at NPV=20 and subtracting pile-up at NPV=10 to estimate the average pile-up per vertex. The corrections for data show linear behavior as a function of NPV, while MC has slight quadratic behavior in the end cap regions around fabs(eta)=2.5-3.0.

Average offset and jet area methods compared for data and MC as a function of the number of primary vertices. The Jet Area method is designed to reproduce the Average Offset corrections (including their eta-dependence) in data.

The pile-up dependence on NPV is very linear for data, while MC requires a small quadratic corrections.

PileUp_NPV_jt320.pdf

Distribution of primary vertices observed in data, compared to Monte Carlo after pile-up reweighing based on the true number of generated pile-up interactions.
ClosureVsPt_Overview2_ak5pfl1.pdf Closure test of MC truth-based jet energy corrections (JEC) on MC.
L5Corr.pdf

Jet energy corrections shown separately for different jet flavors. Gluons (g) have a high color charge compared to quarks, which causes them to fragment to more particles than quarks and results in larger JEC. The high mass of heavy quarks (c, b) also results in fragmentation to more particles than for light quarks (uds), in addition to many heavy quarks being produced in gluon-splitting.

The neutrinos produced in semi-leptonic decays of heavy quarks are not included in the generator-level particle jets when computing the corrections.

MCTruth1_PU.pdf Uncorrected jets with PU. This plot demonstrates the large change in jet response at low pT as pile-up is increased.
MCTruth2_noPU.pdf Pile-up corrected jets. Applying pile-up corrections removes dependence on NPV seen in the plot above. The jet response shows some pT dependence, as it would in a sample without pile-up before JEC is applied.
MCTruth3_noPUplusJEC.pdf PU+MC truth corrected jets. After applying the full set of corrections the jet response is stable versus NPV and jet pT (as well as jet eta). The MC truth correction brings the closure back to one.
ResComp_FSRcorr_residuals_Abseta_PF_DiJetData.pdf

Eta-dependent corrections determined from dijet data. The detector modeling is accure, and the eta-dependent residuals for all jet types are below 2.5% at fabs(eta)<2.4. The residual corrections in the end caps outside tracker coverage are slightly larger, and HF modeling requires a 5 to 10% correction.

The main recommended algorithm is PF(chs), but CALO and JPT are also supported.

MPF_pTbalance_vspT2nd_AK5L2L3.pdf

The 'pT balance' method used for determining absolute JEC with photon+jet (shown) and Z+jet samples is biased by additional jet activity, but agrees well with the Missing-ET projection fraction (MPF) method after extrapolating additional jet activity to zero.

The required extrapolation for the data/MC ratio depends on the reference MC, and is fairly large for Herwig++ (used for cross-check studies), small for Pythia Z2 (used for photon+jet and dijet), and negligible for MadGraph+Pythia (used for Z+jet). The MPF method is insensitive to additional jet activity.

ZGammaJet12.pdf

Data/MC ratio for the absolute scale after combining the photon+jet sample with two Z+jet decay modes. The residual correction required for absolute scale is of the order of 1.5% for all subchannels, and shows no significant pT dependence. Possible pT dependence is covered by extrapolation systematics based on a comparison of Pythia and Herwig fragmentation models and on the uncertainty in single particle response propagated to jets.

composition_stack_single_polished.pdf

Jet composition versus jet eta. The composition shows good agreement in the barrel region, but small differences in the more forward regions, consistent with the measured residual corrections.

Vertical lines indicate the reference region fabs(eta)<1.3 used for determining the absolute scale. The pT dependence in this region is shown in the composition plot below.

composition_difference_polished.pdf Difference of jet composition in data and MC shown in the above plot. The difference plot helps to appreciate the good agreement in the barrel region, and small differences in the end caps outside tracking and in HF.
calcFrac_Frac0_MC.pdf

Jet composition versus jet pT in the barrel region fabs(eta)<1.3. The composition shows good agreement across the full pT range from 30 GeV to 1.5 TeV, consistent with the small size of the measured residual correction.

Vertical lines indicate the pT range 49-114 GeV used for the jet composition plot vs eta shown above.

JECUncert2012_AK5PF_Eta00.pdf Jet energy correction uncertainty vs jet pT at fabs(eta)<1.3.
JECUncert2012_AK5PF_Pt100.pdf Jet energy correction uncertainty vs jet eta at pT=100 GeV.

Topic attachments
I Attachment History Action Size Date Who Comment
PDFpdf ClosureVsPt_Overview2_ak5pfl1.pdf r1 manage 142.8 K 2012-07-06 - 09:48 MikkoVoutilainen JEC performance plots
PDFpdf JECUncert2012_AK5PF_Eta00.pdf r1 manage 18.1 K 2012-07-06 - 09:48 MikkoVoutilainen JEC performance plots
PDFpdf JECUncert2012_AK5PF_Pt100.pdf r1 manage 39.3 K 2012-07-06 - 09:48 MikkoVoutilainen JEC performance plots
PDFpdf L5Corr.pdf r1 manage 140.7 K 2012-07-06 - 09:48 MikkoVoutilainen JEC performance plots
PDFpdf MCTruth1_PU.pdf r1 manage 141.3 K 2012-07-06 - 09:45 MikkoVoutilainen Pile-up performance plots
PDFpdf MCTruth2_noPU.pdf r1 manage 131.5 K 2012-07-06 - 09:45 MikkoVoutilainen Pile-up performance plots
PDFpdf MCTruth3_noPUplusJEC.pdf r1 manage 141.6 K 2012-07-06 - 09:45 MikkoVoutilainen Pile-up performance plots
PDFpdf MPF_pTbalance_vspT2nd_AK5L2L3.pdf r1 manage 18.2 K 2012-07-06 - 09:48 MikkoVoutilainen JEC performance plots
PDFpdf PileUp_NPV_jt320.pdf r1 manage 16.5 K 2012-07-06 - 09:45 MikkoVoutilainen Pile-up performance plots
PDFpdf ResComp_FSRcorr_residuals_Abseta_PF_DiJetData.pdf r1 manage 13.4 K 2012-07-06 - 09:48 MikkoVoutilainen JEC performance plots
PDFpdf ZGammaJet12.pdf r1 manage 16.6 K 2012-07-06 - 09:48 MikkoVoutilainen JEC performance plots
PDFpdf calcFrac_Frac0_MC.pdf r1 manage 26.0 K 2012-07-06 - 09:49 MikkoVoutilainen PF composition cross-check
PDFpdf calcFrac_FracDiff0_MC.pdf r1 manage 22.0 K 2012-07-06 - 09:49 MikkoVoutilainen PF composition cross-check
PDFpdf composition_difference_polished.pdf r1 manage 25.7 K 2012-07-06 - 09:49 MikkoVoutilainen PF composition cross-check
PDFpdf composition_stack_single_polished.pdf r1 manage 30.1 K 2012-07-06 - 09:49 MikkoVoutilainen PF composition cross-check
PDFpdf drawPileUpDataVsMC.pdf r1 manage 17.6 K 2012-07-06 - 09:45 MikkoVoutilainen Pile-up performance plots
PDFpdf h_AvgpTinPF5_stacked_8TeV_NPV20-NPV10_all_dataonly.pdf r1 manage 24.0 K 2012-07-06 - 09:45 MikkoVoutilainen Pile-up performance plots
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Topic revision: r7 - 2013-05-02 - FilipMoortgat
 
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