Non-perturbative renormalisation for overlap fermions

Using non-perturbative techniques we have found the renormalisation factor, Z, in the RI-MOM scheme for quark bilinear operators in quenched QCD. We worked with overlap fermions using the Luescher-Weisz gauge action. Our calculation was performed at β = 8.45 at a lattice spacing of 1/a=2.1 GeV using a value of ρ = 1.4. Our results show good agreement between the vector and the axial vector in the zero mass limit. This shows that overlap fermions have good chiral properties. To attempt to improve the discretisation errors in our results we subtracted the O(a2) terms in one-loop lattice perturbation theory from the Monte Carlo Green functions. In particular we paid attention to the operators for the observable left angle x right angle. We found a value for the renormalisation constants ZMSv2b and ZMSv2a just less than 1.9 at μ = 1/a = 2.1 GeV. (orig.)