Fundamental interactions between electrons and protons, coupling between photons and Z bosons, and the underlying substructure of the proton, can all be probed through scattering experiments designed to measure the parity-violating asymmetry due to a mixing of electromagnetic and weak forces. Our research involves testing the limits of the standard model in search of new physics, by comparing high precision theoretical predictions of this asymmetry, along with the proton's weak charge and the weak mixing angle, to recent experimental measurements. We were ultimately able to achieve results consistent with experimental observations, by accounting for radiative corrections beyond single boson exchange. Our calculations include up to first-order Feynman diagrams containing 1 loop integrals, soft-photon bremsstrahlung, and we account for additional box diagram corrections. We also consider the addition of a new weakly-interacting dark Z boson (Z') to the Standard Model, and investigate how it affects the calculated asymmetry.