Lattice QCD calculation of the proton decay matrix element in the continuum limit -: art. no. 111501

We present a quenched lattice QCD calculation of the a and b parameters of the proton decay matrix element. The simulation is carried out using the Wilson quark action at three values of the lattice spacing in the range a0.1-0.064 fm to study the scaling violation effect. We find only mild scaling violation when the lattice scale is determined by the nucleon mass. We obtain in the continuum limit, (NDR,2 GeV)=0.0090(09)(+5-19) GeV3 and (NDR,2 GeV)=0.0096(09)(+6-20) GeV3 with a and b in a relatively opposite sign, where the first error is statistical and the second is due to the uncertainty in the determination of the physical scale.