Tests of a Particle Flow Algorithm with CALICE test beam data

The studies presented in this paper provide a first experimental test of the Particle Flow Algorithm (PFA) concept using data recorded in high granularity calorimeters. Pairs of overlaid pion showersfrom CALICE2007 test beam data are reconstructed by the PandoraPFA program developed to implement PFA for a future lepton collider. Recovery of a neutral hadron's energy in the vicinity of a charged hadronis studied. The impact of the two overlapping hadron showerson energy resolution is investigated. The dependence of the confusion error on the distance between a 10 GeV neutral hadronand a charged pionis derived for pionenergies of 10 and 30 GeV which are representative of a 100 GeV jet. The comparison of these test beam data results with Monte Carlo simulation is done for various hadron showermodels within the GEANT4 framework. The results for simulated particles and for beam data are in good agreement thereby providing support for previous simulation studies of the power of Particle Flow Calorimetry at a future lepton collider.