Update on Secondaries and Backtracking Validation Bruce Schumm UC Santa Cruz February 22, 2008 Inner Detector Software Meeting

Keeping Statistics on Secondaries Nomenclature: Particle: MC object. “Secondaries” are non- prompt particles. Track: Reconstructed pattern in detector, may or may not be clearly associated with a particle Most reconstructed tracks are not due to secondary particles  generally doesn’t make sense to calculate fraction of tracks due to secondaries It is useful to ask what fraction of secondaries are reconstructed, and properties of associated tracks

Definition of Secondary Particle We have defined a secondary as a particle that originates at a displaced location with either 25mm < r < 360mm 200mm < z < 2000mm but also, the secondary must terminate with r > 1000mm or z > 2300 mm We use the usual  boundaries of Barrel 0 < |  | < 0.8 Transition 0.8 < |  | < 1.6 Endcap1.6 < |  | < 2.5

Statistics for Secondary Tracks TrackCollection "ConvertedXKalmanTracks" (TrackAuthors: xKalmanLegacyCnv ), TrackTruthCollection "ConvertedXKalmanTracksTruth" tracks hits/track. n/event eff. total PIX1 PIX2 PIX3 SCT1 SCT2 SCT3 SCT4 SCT5to9 Straws total in barrel in trans in endcap TrackCollection "ConvertedIPatTracks" (TrackAuthors: iPatLegacyCnv iPatLegacyCnvBremFit ), TrackTruthCollection "ConvertedIPatTracksTruth" tracks hits/track.. n/event eff. total PIX1 PIX2 PIX3 SCT1 SCT2 SCT3 SCT4 SCT5to9 Straws total in barrel in trans in endcap Sample Secondaries Statistics We have yet to include this in the default InDetRecStat output, but plan to soon.

Under Development: automated BackTrackRTT package based on the InDetRecStat ntuple 1 1 We will shortly have a discussion about merging InDetRecStat and TrkValidation

For now, using ResolvedTRTSeededTracks (require track parameter fit for residuals, fake rates, so can’t use more efficiency TRTSeededTracks). Developing two validation samples: E t = 20 GeV Gamma Conversions P t = 10 GeV K S 0 decays Initial analysis script is modest: residuals hit distributions efficiencies fake rates.

Defining “trackable” tracks For non-prompt tracks, include “z exit ” and “r org ” as performance parameters, along with p  and .

Tracking effic- iency vs. p t and vs. r org may be most interesting (use p t cut of 1 GeV/c for all but p t distribution, and z exit cut of 3000).

PP PP   All Findable ParticlesMissed by Backtracking All Findable ParticlesMissed by Backtracking

Back to validation… As mentioned, need to explore inclusion of TRT segments in InDetRecStat Thoughts about Validation Material Current data files: single muon, multi muon, Z   all probably useful. Might add 20 GeV photons for monitoring coversion recovery. Thinking still nascent and we are open to suggestions.