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Fast Simulation of the Dirc with Pravda. Rolf Andreassen / B. Meadows University of Cincinnati. Outline. Dirc Photon Ring Dictionary Some performance Plots Adaptability Summary. What Do We Simulate?. The Dirc must provide PID information. This means ( , , N ) for each track.
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Fast Simulation of the Dirc with Pravda Rolf Andreassen / B. Meadows University of Cincinnati Rolf Andreassen/Brian Meadows, U. Cincinnati
Outline • Dirc Photon Ring Dictionary • Some performance Plots • Adaptability • Summary Rolf Andreassen/Brian Meadows, U. Cincinnati
What Do We Simulate? • The Dirc must provide PID information. This means (, , N) for each track. • These quantities can be combined into a probability where <> is expected Cherenkov angle (depends on particle hypothesis, of course) and is the expected number of photons. • is the hardest quantity to simulate! Rolf Andreassen/Brian Meadows, U. Cincinnati
Dirc Ring Dictionary • This was invented to provide the efficiency for photons to be detected and reconstructed given (p,,) at entry to bar. • Why is this important? • Without this, the Dirc efficiency shows dips in efficiency just above the Cherenkov thresholds. • Measurement of number of photons N is important in these regions Rolf Andreassen/Brian Meadows, U. Cincinnati
Value Added by Ring Dictionary? • Full Geant4 simulation used • Tracks swum out to Dirc • Photons generated during swim through bar (multiple scattering) • Photons tracked through bar and H2O stand-off box (SOB) to PMT’s Rolf Andreassen/Brian Meadows, U. Cincinnati
Value Added by Ring Dictionary? • Event fully reconstructed using BaBar code • Effect of event environment is included. • = # of reconstructed photons £ cos/sin2 (radians) (degrees) Tabulated by azimuth , dip at bar and Cherenkov. Rolf Andreassen/Brian Meadows, U. Cincinnati
# Tracks # Photons Performance – First Look 10,000 B0 +- and recoil Momentum (GeV/c) Cos Rolf Andreassen/Brian Meadows, U. Cincinnati
# Tracks # Photons Performance – First Look Rolf Andreassen/Brian Meadows, U. Cincinnati
Performance – First Look Average # Photons Cos Rolf Andreassen/Brian Meadows, U. Cincinnati
Performance – First Look Average # Photons Cos Rolf Andreassen/Brian Meadows, U. Cincinnati
Performance – First Look # Photons Azimuth (radians) Rolf Andreassen/Brian Meadows, U. Cincinnati
Performance – First Look Cherenkov Angle (radians) Momentum p (GeV/c) Rolf Andreassen/Brian Meadows, U. Cincinnati
Performance • Rolf’s plots here: Rolf Andreassen/Brian Meadows, U. Cincinnati
Adapt to Different Dirc ? • Change detector: • If no change in time resolution, can simply scale using new QE: • In general, event environment in new time window will differ significantly Probably need to make ring dictionary using (NEW) full Geant4. Rolf Andreassen/Brian Meadows, U. Cincinnati
Summary • We have a simulation that is fast and (with work) somewhat realistic. • Experience in physics studies is still required • A few questions in implementation remain. • It works with the present Dirc (with H2O SOB and PMT’s) • Upgrade in Dirc readout will require a new, full Geant4 production of new ring dictionary. Rolf Andreassen/Brian Meadows, U. Cincinnati