MissingETComposition Object Adam Yurkewicz (Stony Brook) Donatella Cavalli (Milan) Peter Loch (Arizona) Silvia Resconi (Milan) Rolf Seuster (MPI) Thanks also to Pierre-Antoine Delsart, Marcin Nowak, Scott Snyder

Motivation for a New MissingET Data Structure Useful to have more MissingET information available than just final sums (MET_RefEle, MET_RefJet, MET_CellOut, …) – i.e. would like to easily answer the question “What muons were used to build the MissingET muon term?” Improve infrastructure to properly remove overlaps between different types of objects inside the MET algorithm Provide information needed to calculate MET significance Simplify analysis; this should usually be the one and only object users retrieve from the AOD for MissingET information 2

MissingETComposition Structure Object PointerWeight (px) [float] Weight (py) [float] Weight (pt) [float] Status Word [Unsigned short] Jet 1Wpx_jet_1Wpy_jet_1Wet_jet_1P4SignalState:: CALIBRATED Jet 2Wpx_jet_2Wpy_jet_2Wet_jet_2P4SignalState:: CALIBRATED Muon 1Wpx_muon_1Wpy_muon_1Wet_muon_1COMBINED Muon 2Wpx_muon_2Wpy_muon_2Wet_muon_2 SPECTROMETER Electron 1Wpx_ele_1Wpy_ele_1Wet_ele_1EM Cluster 1Wpx_clus_1Wpy_clus_1Wet_clus_1P4SignalState:: CALIBRATED …………… 3

MissingETComposition Structure 3 weights per object are object’s contribution to MissingET, sumet – Weight is product of all differences between reconstructed object’s stored px,py,pz, and what is used by MissingET algorithm 16-bit status word holds flags about object calibration/state information (most bits currently unused) From the MissingETComposition object, can calculate the MET terms: /////////////////////////// const MissingETComposition *metcomp; storeGate->retrieve(metcomp,”MET_RefComposition”); MissingETComposition::const_iterator fJet(metcomp->beginIterator ()); MissingETComposition::const_iterator lJet(metcomp->endIterator ()); float my_METRefJet_x = 0.0; for (; fJet != lJet; fJet++) { my_METRefJet_x -= (*fJet)->px()*fJet.getParameter().wpx(); } 4

Keep incremental sums METRefEleTool MET_RefEle_1 Weight_1= -RefEle1/ele_1 MET_RefEle_1+2 Weight_2= [RefEle_1 –RefEle_2]/ele_2 MET_RefEle Weight n= [RefEle_n-1 - RefEle_n]/ele_n Ele_1, weight_ele_1, status_word_ele_1 Ele_2, weight_ele_2, status_word_ele_2 …. Ele_n, weight_ele_n, status_word_ele_n Register information in METComposition object Jet_1, weight_jet_1, status_word_jet_1 Jet_2, weight_jet_2, status_word_jet_2 …. Jet_n, weight_jet_n, status_word_jet_n METRefJetTool …. METRef*** Backnav to cells Select electrons from input electron container ele_1 ele_2 ele_n ele_3 Set status words with calibration/state information sw_1 sw_2sw_n Compute weights that objects contribute to MET Input Electron Collection … METComposition Object 5

Current Status Code in svn, nightly – MissingET – MissingETEvent METComposition object not written to ESD/AOD by default; can be switched on in job options – Muons not filled into METComposition object yet, coming soon Size on disk: 3.1 kb/ev over 1000 J3 events, – MET_CellOut ~200 clusters/event 6

Validation 7 Sanity check: Read back MissingETComposition map from AOD and calculate each MET term, compare to standard METRef* containers

Jet Weights in J3 Sample 8 Weights for jets with pt > 20 GeV for J3 sample Difference from 1 from overlap removal and fact that numerical inversion not applied in MET algorithm

Example Usage Run , event , MET_RefFinal_MET = 50 GeV From METComposition, know 21 topo clusters contribute to MET_CellOut term (+ have all kinematic information) 2 jets contribute to MET_RefJet term (+ have all jet info) METComposition can be used by ATLAS event displays to show which objects contribute to MET terms (and how much) 9

Future Finish muon tool After that, it’s ready for use – Would like to backport into 15.6.x to make available for coming data Provide some user-friendly access methods 10