  By determining the quark momentum fractions of the octet baryons from N_f=2+1
lattice simulations, we are able to predict the degree of charge symmetry
violation in the parton distribution functions of the nucleon. This is of
importance, not only as a probe of our understanding of the non-perturbative
structure of the proton but also because such a violation constrains the
accuracy of global fits to parton distribution functions and hence the accuracy
with which, for example, cross sections at the LHC can be predicted. A
violation of charge symmetry may also be critical in cases where symmetries are
used to guide the search for physics beyond the Standard Model.
