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, 2016 1 / 7
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 4 3 2 1 1 2 0 ALAS Preliminary -1 s = 13 ev, 15.5 fb WW selection Data 2015+2016 Fit bkg estimation HV Model A m=1.5 ev HV Model A m=2.4 ev Fit exp. stats error 2 1 1.5 2 2.5 3 3.5 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, 2016 2 / 7 [1]
In Situ Calibration Methods After initial MC calibration, derive additional in situ calibrations from data t t (Forward Folding) Multi Jet γ+jet 0 150 500 700 00 1500 2000 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 200 350 GeV 2.1% uncertainty Matthew Epland In Situ JES of Large Radius Jets Nov. 3, 2016 3 / 7
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, 2016 4 / 7
γ+jet Balance ref / p lead jet p 1.08 1.06 1.04 1.02 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 / 0.1 140 120 Data15 Data15 Fit Pythia8 Pythia8 Fit 350 < p µ Data15 µ Pythia8 ref [GeV] < 400 ALAS = 0.955 ± 0.006 Work in Progress = 0.980 ± 0.002 1 0 0.98 0.96 0.94 80 60 Data / MC 0.92 1.02 1 0.98 0.96 0.94 0 0 200 300 400 500 600 700 800 900 00 ref p [GeV] 40 20 0 0.6 0.8 1 1.2 1.4 B Matthew Epland In Situ JES of Large Radius Jets Nov. 3, 2016 5 / 7
γ+jet Systematics Fractional Variation 0.04 0.035 0.03 0.025 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 0.02 0.015 0.01 0.005 0 0 0 200 300 400 500 600 700 800 900 00 ref p [GeV] Matthew Epland In Situ JES of Large Radius Jets Nov. 3, 2016 6 / 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, 2016 7 / 7
Backup Matthew Epland In Situ JES of Large Radius Jets Nov. 3, 2016 8 / 7
γ+jet Event Selection Photons p γ > 180 GeV η γ < 1.37 ight identification and isolation (E 40 < 0.022p + 2.45 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, 2016 9 / 7
γ+jet B vs p ref B 2 1.8 1.6 1.4 1.2 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 Data15 140 120 0 Events / ( GeV x 0.1) 1 0.8 0.6 0.4 0.2 80 60 40 20 0 0 0 200 300 400 500 600 700 800 900 00 ref p [GeV] 0 Matthew Epland In Situ JES of Large Radius Jets Nov. 3, 2016 / 7
Small Radius In-Situ JES /Response Response MC Data 1.1 1.05 1 0.95 0.9 0.85 0.8 anti-k t R=0.4, EM+JES Data 2015 20 30 2 2 2 γ+jet Z+jet Multijet ALAS Preliminary s = 13 ev, 3.2 fb η <0.8 otal uncertainty Statistical component 3 p jet -1 3 2 [GeV] [2] Matthew Epland In Situ JES of Large Radius Jets Nov. 3, 2016 11 / 7
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-2016-055, CERN, Geneva, Aug, 2016. http://cds.cern.ch/record/2206137. [2] Public plots: Jet energy scale uncertainties updated for ICHEP 2016 using full 13 ev 2015 dataset, Aug, 2016. https://atlas.web.cern.ch/atlas/groups/physics/plos/jem-2016-0/. Matthew Epland In Situ JES of Large Radius Jets Nov. 3, 2016 12 / 7