In Situ Jet Energy Scale Calibration of Large Radius Jets

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1 In Situ Jet Energy Scale Calibration of Large Radius Jets Matthew Epland Duke University Nov. 3, 2016 US LUA, LBNL Matthew Epland In Situ JES of Large Radius Jets Nov. 3, / 7

2 X Why Calibrate Large Radius Jets? Heavy objects decaying to multiple quarks are conveniently reconstructed as large radius jets Substructure tagging opens a window on processes like X t t, V V, HH Without a calibrated Jet Energy Scale (JES) discoverable features would be smeared and measurements would be off W + W q q q q Large Radius Jets Events / 0.1 ev Pull ALAS Preliminary -1 s = 13 ev, 15.5 fb WW selection Data Fit bkg estimation HV Model A m=1.5 ev HV Model A m=2.4 ev Fit exp. stats error M JJ [ev] Begin by calibrating JES from Monte Carlo (MC) simulations: MC, Reco MC, ruth MC Calibration = p /p Matthew Epland In Situ JES of Large Radius Jets Nov. 3, / 7 [1]

3 In Situ Calibration Methods After initial MC calibration, derive additional in situ calibrations from data t t (Forward Folding) Multi Jet γ+jet p [GeV] γ+jet Multi Jet Forward Folding J γ 2% uncertainty j2 j3 2% uncertainty j1 MC Data (µ, σ ) (µ, σ) Fit µ /µ σ /σ Valid on GeV 2.1% uncertainty Matthew Epland In Situ JES of Large Radius Jets Nov. 3, / 7

4 γ+jet Direct Balance Method B = p J /p ref R ( p J ) = BData /B MC p γ p ref = pγ cos ( φ) φ π p J Extra Radiation, Veto! Large radius jet: anti k t R = 1.0, trimmed Extra radiation: anti k t R = 0.4 Matthew Epland In Situ JES of Large Radius Jets Nov. 3, / 7

5 γ+jet Balance ref / p lead jet p Data15 Pythia8 Stat. Syst. ALAS Work in Progress -1 s=13 ev, L dt = 3.2 fb lead jet γ-jet Events, η < 0.8 anti-k t R = 1.0, LC rimmed Events / Data15 Data15 Fit Pythia8 Pythia8 Fit 350 < p µ Data15 µ Pythia8 ref [GeV] < 400 ALAS = ± Work in Progress = ± Data / MC ref p [GeV] B Matthew Epland In Situ JES of Large Radius Jets Nov. 3, / 7

6 γ+jet Systematics Fractional Variation Stat. Syst. Statistical MC Modeling φ Selection Event opology Selection γ Purity γ Energy Scale and Res. ALAS Work in Progress -1 s=13 ev, L dt = 3.2 fb lead jet γ-jet Events, η < 0.8 anti-k t R = 1.0, LC rimmed ref p [GeV] Matthew Epland In Situ JES of Large Radius Jets Nov. 3, / 7

7 Summary Uncertainty in the JES calibration is a major systematic for many large radius jet analyses, such as diboson resonance searches Combining the in situ methods should produce a calibration with 2% uncertainty he new in situ calibration will be approximately a factor of two improvement over the current calibration Matthew Epland In Situ JES of Large Radius Jets Nov. 3, / 7

8 Backup Matthew Epland In Situ JES of Large Radius Jets Nov. 3, / 7

9 γ+jet Event Selection Photons p γ > 180 GeV η γ < 1.37 ight identification and isolation (E 40 < 0.022p GeV) Large Radius Jets (J 1 ) p J1 > 20 GeV η J 1 < 0.8 Overlap removal: R γ, J1 > 0.2 Small Radius Jets (j 2 ) Cleaned + JV 0.59 Overlap removal: R γ, j2 > 0.4, R J1, j 2 > 1.0 opological Selections φ > 2.8 p j2 < max ( ) 15 GeV, 0.1 p ref Matthew Epland In Situ JES of Large Radius Jets Nov. 3, / 7

10 γ+jet B vs p ref B ALAS Work in Progress -1 s=13 ev, L dt = 3.2 fb lead jet γ-jet Events, η < 0.8 anti-k t R = 1.0, LC rimmed Data Events / ( GeV x 0.1) ref p [GeV] 0 Matthew Epland In Situ JES of Large Radius Jets Nov. 3, 2016 / 7

11 Small Radius In-Situ JES /Response Response MC Data anti-k t R=0.4, EM+JES Data γ+jet Z+jet Multijet ALAS Preliminary s = 13 ev, 3.2 fb η <0.8 otal uncertainty Statistical component 3 p jet [GeV] [2] Matthew Epland In Situ JES of Large Radius Jets Nov. 3, / 7

12 References [1] Search for resonances with boson-tagged jets in 15.5 fb 1 of pp collisions at s = 13 ev collected with the ALAS detector, ech. Rep. ALAS-CONF , CERN, Geneva, Aug, [2] Public plots: Jet energy scale uncertainties updated for ICHEP 2016 using full 13 ev 2015 dataset, Aug, Matthew Epland In Situ JES of Large Radius Jets Nov. 3, / 7