1. Analysis Meeting – April 17 '07 Status and plan update for single hadron scale check with minimum bias events N. Davidson

2. Status Using official production Minimum bias at 14TeV (no pile-up)  approx 50,000 events  Athena version 11.0.42 Minimum bias at 900GeV  approx 100,000 events  Athena version 11.0.5 Single 3GeV pions  approx 100,000 events  Athena version 11.0.41 AOD data dumped to an Ntuple. Code runs over the Ntuple to match extrapolated tracks to caloTopoClusters

3. Status Status from JetRec Presentation:  900 GeV minimum bias sample gave E/p approx 4% greater than single pion sample after cuts.  14 TeV minimum bias gave E/p approx 8% higher than single pions sample after cuts. Cuts only made to remove contamination to the energy of the clusters.

4. Misidentified Pions Pions only make up around 70% of tracks  other hadrons: don't seem to bias the E/p too much  electron: only make up < 3% of tracks deposit more energy as they are electromagnetic cause a bias in the E/p of approx 2% in both 900GeV and 14TeV sample Identification of electron tracks  Energies too low to use the usual identification  In minimum bias sample they come from conversion of photons in the inner detector.

5. Electron Idenfitication Electrons produced after the first ID layer x,y truth production position for pions x,y truth production position for electrons

6. Electron Identification Require at least one hit in B Layer Could also use TRT high threshold hits Leave cuts soft for the moment as csc statistics are low Number of B Layer hits electrons pions electrons pions Ratio of TRT high threshold hits

7. E/p after electron identification E/p minimum bias 14TeV E/p minimum bias at 900GeV minimumbias 3GeV single pion minimum bias single pions

8. Ideas to try Started working with the ESDs:  looking at strip width to removed charged + neutral contamination.  looking at track segments. Improve track isolation cut. remove charged contamination not leaving a full track. Old ideas  Just measure and subtract background. Need to remove cluster based cuts. Tried before and didn't look too good, but could still improve the E/p?

9. Other Plans Short term:  Only looked at 3GeV single pions so far. Will produce single pions from 1GeV upwards to see the E/p and bias at each energy range  Need to re-reconstruct minimum bias data with Athena version 12.0.6 Use Calibrated TopoClusters (default in 12?) Look at trigger effects Longer term:  Looks at pion jet reconstruction For pions over 10GeV. Will need to use atlfast or stats are too low.