Particle Flow Calorimetry and ILC Detector Design - Center for High ...

CCAST-Tsinghua School, 26/4/2009 Mark Thomson 23iii) Topological Cluster AssociationBy design, clustering errs on side of cautioni.e. clusters tend to be splitPhilosophy: easier to put things together than split them upClusters are then associated together in two stages:• 1) Tight cluster association – clear topologies• 2) Loose cluster association – fix what’s been missedPhoton IDPhoton ID plays important roleSimple “cut-based” photon ID applied to all clustersClusters tagged as photons are immune from associationprocedure – just left aloneWon’t mergeWon’t mergeCould get mergedγγγ