  One of the most important requirements for a detector at the ILC is good jet
energy resolution. It is widely believed that the particle flow approach to
calorimetry is the key to achieving the ILC goal of a di-jet invariant mass
resolution sigma_m/m < Gamma_Z/m_Z. This paper describes the current
performance of the PandoraPFA particle flow algorithm. For simulated light
quark jets in the Tesla TDR detector, the jet energy resolution achieved is
better than sigma_E/E ~ 3.4% for jet energies in the range 45-250 GeV. This
represents the first demonstration that Particle Flow Calorimetry can reach the
ILC jet energy resolution goals.
