A new approach to η' on the lattice

We perform an η' mass analysis based on a total of 1130 dynamical gauge field configurations, with 5 different quark mass values on lattices of size 163 x 32 (SESAM) and 243 x 40 (TχL) at β = 5.6. We employ the stochastic estimator technique and spectral methods to deal with the disconnected piece of the flavour singlet correlation function. We demonstrate that very early plateau formation in the local η' mass can be achieved by first ground state projecting the connected piece of its correlator