Missing E T Reconstruction in ATHENA Using Reconstructed Objects

1. Missing ET Reconstruction in ATHENA Using Reconstructed Objects Bryan Caron (Jim Pinfold) University of Alberta Calibration Workshop -- Ringberg July 2002

2. Calculating Etmiss Using Reconstructed Objects • Calculate Etmiss using reconstructed objects. • Introduce new additional TOP Level Algorithm: MissingETRecObjectBuilder • Access contents of reconstructed object containers for e/gamma, Jets (Kt + cone), Taus, EG: egammaContainer, etc. • For now keep to existing calorimeter objects • Expand to include muon information, etc. • Use the structure of other reconstruction packages ( egammaREec, tauRec) as a foundation Calibration Workshop -- Ringberg July 2002

3. Calibration Using Reconstructed Objects • Four basic kinds of reconstructed objects will be used: e/gamma, jets (Kt + Cone), taus, muons. • Next look at cells outside of the reconstructed objects and study their origin, eg: • Tails from reconstructed objects? • Isolated MIPs, track-able from the ID (using energy flow)? Etc? • Expand the definition of reconstructed object (e/g, jet,t,m) for Etmiss calibration, if necessary. Calibration Workshop -- Ringberg July 2002

4. Looking at Cells Outside of Reconstructed Objects • Define optimal method to ID cells outside of clusters • Calibrate cells outside of “reconstructed objects” (or “redefined” reconstructed objects) using Minimum Bias events. Calibration Workshop -- Ringberg July 2002

5. Where are we now? • Currently debugging creation of the new TOP LEVEL algorithm and methods of access to reconstructed object containers. • The method we are following is complementary to the approach of Donatella and Sylvia…BUT longer term • Perform calibration by minimizing missing energy resolution using as elements the energy of the reconstructed objects plus those cells NOT in the reconstructed objects. Where are we going Calibration Workshop -- Ringberg July 2002