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The general iterative tracking steps are outline below. The main idea of iterative tracking is to find different collections of tracks and remove them from the list of track candidates used in the next iteration/step. Only steps 0-4 are used in the online version of iterative tracking. Pixel tracks are used as seeds for iterative tracking, which produces full tracks.
Steps:
0: prompt tracks, high pT
seeds: pixel tripletstriplets (pT>0.6 GeV)
1: prompt tracks, low pT
seeds: pixel tripletstriplets (pT>0.2 GeV)
2: prompt tracks, high pT (recovery)
seeds: pixel pairs + vertexvertex (pT>0.6 GeV)
3: displaced tracks
seeds: pixel triplets (pT>0.3 GeV, d0<1.5cm)
4: displaced tracks - barrel
seeds: pixel-strip mixed tripletstriplets (pT>0.6 (0.4) GeV, d0<1.5cm)
5: displaced tracks
seeds: TIB, TID, TEC pairspairs (pT>0.7 GeV, d0<2.5cm)
6: displaced tracks (more displaced)
seeds: TOB, TEC pairspairs (pT>0.6 GeV, d0<6cm)
9: Muons
seeds: standalone muonsmuons (pT>2 GeV)
10: Muons
seeds: tracker muonsmuons (pT>10 GeV)