Nucleon charge symmetry breaking and parity violating electron-proton scattering

Abstract

The consequences of the charge symmetry breaking effects of the mass difference between the up and down quarks and electromagnetic effects for searches for strangeness form factors in parity violating electron scattering from the proton are investigated. The formalism necessary to identify and compute the relevant observables is developed by separating the Hamiltonian into charge symmetry conserving and breaking terms. Using a set of SU(6) nonrelativistic quark models, the effects of the charge symmetry breaking Hamiltonian are considered for experimentally relevant values of the momentum transfer and found to be less than about 1%. The charge symmetry breaking corrections to the Bjorken sum rule are also studied and shown to vanish in first-order perturbation theory.