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

Abstract 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 F 2 π + + F 2 π − −2 F 2 π 0 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 't Hooft–Veltman prescription for γ 5 , taking particular care of mixing effects. The contribution is found to be of O ( f π 2 / Q 2 ), relative to the leading contribution to the moment of F 2 π + .