Eigenvalue Decomposition of Meson Correlators

Abstract

Euclidean space hadronic correlators are computed in quenched QCD at small quark mass using truncations of quark propagators which include or exclude low eigenvalue eigenmodes of the Dirac operator. High modes provide the dominant contribution to parity averaged correlators, especially at short distances. Differences of correlators of opposite parity receive most of their contributions from low modes and are much smaller in size than parity averages at short distances. The pion propagator in any correlator to which it couples receives a large contribution from low modes, while the tensor meson correlator receives a tiny contribution from low eigenmodes.