Continuum limit of proton decay matrix elements in quenched lattice QCD

We present a lattice QCD calculation of the parameters alpha and beta which are necessary in the theoretical estimation of the proton lifetime in grand unified theories (GUTs) using chiral lagrangian approach. The simulation is carried out using the Wilson quark action at three gauge coupling constants in the quenched approximation. We obtain |alpha(2GeV)|=0.0091(08)(^{+10}_{-19})GeV^3 and |beta(2GeV)|=0.0098(08)(^{+10}_{-20})GeV^3 in the continuum limit where the first error is statistical and the second one is due to scale setting.