Jet Plus Tracks Subgroup of Jet MET RDMS

Jet Plus Tracks Sub-group of Jet. MET: RDMS members: I. Vardanyan, N. Ilina, O. Kodolova, A. Nikitenko (convener) AN 2009 -031, PAS JME-09 -002 1. A. Nikitenko (IC/ITEP), RDMS meeting, 2. March. 2009

Jet+tracks algorithm The goal of algorithm: correct calorimeter jet energy to the energy of particles at vertex. out-of-calo-cone track in-calo-cone track Basic algorithm steps: Df. 5 =0 Df= 0. 5 Jet axis 0. ZSP and PU off-set corr. 1. Subtract average expected response of “in-calo-cone” tracks from calo jet energy and add track momentum 2. Add momentum of “out-of-cone” tracks

Step 0: ZSP corrections To be extracted from non ZSP data usingle jet triggers

Step 1: correction for response of in-calo-cone tracks EJet = EJetcalo – S<Etrkcalo> + Sptrk , <Etrkcalo> from data without ZSP

Response of pions from TB 06 no zero suppression

In-calo-cone tracks corrections with TB “jets” Jet was formed from charged pions (p-) randomly selected from the data. Number of pions in jet is fixed: jet consists of 6 pions of 2 Ge. V 4 pions of 3 Ge. V 2 pion of 4 Ge. V 1 pion of 5 Ge. V thus true jet energy is 37 Ge. V Average particle response (see previous slide) was subtracted from jet raw energy and replaced by track momentum

Single particle response: effect of ZSP (MC study) Input to JPT: non ZSP response of single pions Effect of ZSP on single pion response

Step 2: adding out-of-calo-cone tracks EJet = EJet+ Sptrk (trks 1, 2, 3 in fig)

Steps 0 -2 in one plot

Take into account tracker inefficiency (I) DEin-cone = ntrkin-cone(p. Tbin, hbin) x (1 -etrk)/etrk x (<pbin> - <Ecalo>) DEout-of-cone = ntrkout-of-cone(p. Tbin, hbin) x (1 -etrk)/etrk x <pbin> etrk = F(p. Tbin, hbin) – track finding efficiency

Jet Energy Scale and tracker inefficiency

JES uncertainty due to single particle response

Performance for |h|<1. 4 Jet Enery Scale ETreco / ETgen Resolution: s(ETreco / ETgen)/m(ETreco / ETgen)

Performance for 1. 4<|h|<2. 0 Jet Enery Scale ETreco / ETgen Resolution: s(ETreco / ETgen)/m(ETreco / ETgen)

Current JES vs h Still need to take into account ECAL crystal calibration and more accurate response function

Calo vs PF vs JPT ET >40 Ge. V, barrel Performance in CMSSW_2_2_3, full sim. after L 2 L 3 corrections; “Official” Jet. MET plot ET> 40 Ge. V, barrel Latest PF improvements for 31 X vs JPT and calo in 2_2_3 (see more in Michele’s talk) Plot provided by P. Janot, no L 2 L 3 corrections applied

Work in progress to improve JPT for 31 X releases It was Monte-Carlo. Need time to commission JPT using real data: ZSP, single particle response, tracker efficiency from data;

Track-corrected MET Frank Golf et al. tc. MET = MET(corrected for m) – p + 〈E〉 CMSSW_1_6_X (Replacing expected calorimeter response with track momentum) momentum Case where we don’t expect MET … Case where we have true MET … tc. MET N(MET>30) ≈ 3 N(tc. MET>30) N(MET>30) ≈ N(tc. MET>30) Missing Energy (Ge. V) # of evts with MET>30 Ge. V (in Z’s) faked by detector resolution and other effects: reduced by factor ~3, while # of W’s almost unaffected as expected. Meeting with LHCC referees Jan 19, 2009 18

Performance for |h|<1. 4 Jet Enery Scale ETreco / ETgen Resolution: s(ETreco / ETgen)/m(ETreco / ETgen) ZSP corrections: corrections for zero suppression on calo sells