Higher-twist contribution to pion structure function: 4-Fermi operators Original Research Article

We present quenched lattice QCD results for the contribution of higher-twist operators to the lowest non-trivial moment of the pion structure function. To be specific, we consider the combination F2π++F2π−−2F2π0 which has I=2 and receives contributions from 4-Fermi operators only. We introduce the basis of lattice operators. The renormalization of the operators is done perturbatively in the MS scheme using the ʹt Hooft–Veltman prescription for γ5, taking particular care of mixing effects. The contribution is found to be of O(fπ2/Q2), relative to the leading contribution to the moment of F2π+.