1. November 6, 2004Carl Bromberg, FNAL LAr Exp. Workshop Nov. 4-6, 20041 Particle ID, energy resolution, neutrino flavor tagging, efficiencies, backgrounds, and the kitchen sink Carl Bromberg Michigan State University & Fermilab (2004) What have we learned from MC and event display scanning?

2. November 6, 2004Carl Bromberg, FNAL LAr Exp. Workshop Nov. 4-6, 20042 MC  interactions A.P. generated –Electromagnetic showers due to an electron, pi-zero, or  –(NeuGen) -interactions in LAr: Charged Current Neutral Current with energy spectrum of the off-axis neutrino beam GEANT simulation of energy deposited by produced particles as they propagate (or decay) in LAr. Record “drift” distance and charge (within 5 mm of drift of a track) on 5 mm pitch wire planes. Instructions on FLARE website to DISPLAY -events www-off-axis.fnal.gov/flare/detector_simulation.htm

3. November 6, 2004Carl Bromberg, FNAL LAr Exp. Workshop Nov. 4-6, 20043 Sample e -> e + hadrons

4. November 6, 2004Carl Bromberg, FNAL LAr Exp. Workshop Nov. 4-6, 20044 What NC rejection is needed? Most (80%) NC events have observed energies below 1.5 GeV or above 3 GeV Near 2 GeV, rejecting 95% of the NC events reduces this background to half the beam e contamination.

5. November 6, 2004Carl Bromberg, FNAL LAr Exp. Workshop Nov. 4-6, 20045 NC events (E observed, 1.5 - 3.5 GeV)

6. November 6, 2004Carl Bromberg, FNAL LAr Exp. Workshop Nov. 4-6, 20046 Scanning rules Develop scanning rules to classify events as CC e –Select events with observed energy between 1.5 to 3.5 GeV –Where is the primary vertex? back track to common point beware of backward moving tracks vertex obscuration, can we afford to reject? –How many clear tracks leave the vertex and travel for at least 2 cm with a minimum ionizing signature –Do any of these tracks develop into electromagnetic shower? Train scanners to apply scanning rules Evaluate CC efficiency and NC rejection

7. November 6, 2004Carl Bromberg, FNAL LAr Exp. Workshop Nov. 4-6, 20047 Rejection of coherent  0 Feared background: coherent production Use MC generated “events” -- EM showers. Start at earliest hit and add energy depositions for 2 cm of track Cut around 1 mip (2 MeV/cm) –82% efficient for e –91% rejection of  0 –93% rejection of  electron showers Energy deposited in first 2 cm  0 -> 2  - showers  - showers

8. November 6, 2004Carl Bromberg, FNAL LAr Exp. Workshop Nov. 4-6, 20048 Outlook First look is very encouraging If full scanning tests confirm –need to code and tune the rules –show automatic scanning gives the same results on new events May convince skeptics of advantages offered by LAr technology