Highlights of the SiD -Iowa Particle Flow Algorithm

1. Highlights of the SiD-Iowa Particle Flow Algorithm • Previous (LOI) version of PFA was for up to 500 GeV collider energy. • Even at 500 GeV performance sufficient, but could be improved. • Established a ground-up approach: • Targeted diagnostics for each piece of the algorithm to evaluate each piece. • Photon reconstruction: • Once photons are reconstructed, the hits are taken out from use. • An anti veto is in place which checks “photon-hits” for fakes and treats them as hadrons. • Sub-cluster categories (clump purity) • Clump (sub-cluster) purity was not good enough: make smaller (don’t use NN). • Linking probabilities of sub-clusters (discriminating variables, likelihood) • Use identical clustering for linking probability and shower reconstruction. • Add likelihood method with several discriminating variables. • Shower reconstruction (two passes):  IN PROGRESS • Form a high purity skeleton with all tracks treated similarly. • Add hits in second pass with adjudication between nearby showers.

2. Highlights of the SiD-Iowa Particle Flow Algorithm Clump reconstruction performance Variables in likelihood used for linking Discrimination improves significantly when angles b and c are added in the likelihood