Charge symmetry violation: An NNLO study of partonic observables

Charge and isospin symmetry violations to valence and sea distribution functions in the nucleon are evaluated (at low resolution scale) by means of a meson cloud model and light-cone quark wave functions. Their perturbative evolution is implemented at next-to-next-to-leading order (NNLO) using an original evolution code in order to include the perturbatively generated strange–antistrange asymmetry typical for the three loop evolution expansion. Charge symmetry violating QED effects are also added and the distributions, evolved at the experimental scale, are compared with available information. The role of non-perturbative effects is emphasized in the interpretation of the, so-called, NuTeV anomaly and new experiments at very high energy.