1 ORCA Muon Seeding Rick Wilkinson

2 Pattern Recognition Pattern: group of segments representing a single muon Start from pairs of segments from different DetLayers Try to add segments from other DetLayers Segments can’t be used for more than one pattern Single-segment seeds allowed in cracks at ||= 0.2, 1.6, and 1.7

3 Direction Estimate Use some heuristic to pick the “best” segment –  2, # of hits, direction w.r.t. origin – Can probably be optimized more Get the  direction from that segment – The whole muon depends on one segment! Use the direction to the origin for the  direction

4 Momentum Estimation DT: – Use a weighted mean of all segment pairs, based on  – Custom p T parametrization seems to work better than Shih- Chuan’s CSC: – Use Shih-Chuan’s parametrization, based on  and  – Only use pair from innermost stations Since magnetic field dies off so fast Better to take weighted mean of ME1-ME2 and ME1-ME3? Overlap – Make separate seeds for DT-DT, DT-CSC, and CSC-CSC pairs – Use Shih-Chuan’s p T parametrization – For DT-CSC pair, take best segment from endcap To avoid 2-D DT segments

5 Interfaces MuonSeedVPatternRecognition: – Input is DT & CSC segment labels, from the ParameterSet – Output is a vector MuonSeedVFinder: – Input is a MuonRecHitContainer, representing a pattern – Output is a vector MuonSeedPtExtractor: – Wraps Shi-Chuan’s parametrization – Returns a p based on two input segments MuonSeedVCleaner: – Modifies a TrajectorySeedCollection Driver code in plugins/MuonSeedGenerator.cc

6 Conclusion ORCA Seed Generator already conforms to what could be the standard virtual interfaces.