Contributions from gamma Z box diagrams to parity violating elastic e-p scattering
Physical Review D
Parity-violating elastic electron-proton scattering measures Q weak for the proton, Q(W)(p). To extract Q(W)(p) from data, all radiative corrections must be well-known. Recently, disagreement on the gamma Z-box contribution to Q(W)(p) has prompted the need for further analysis of this term. Here, we support one choice of a debated factor, go beyond the previously assumed equality of electromagnetic and gamma Z structure functions, and find an analytic result for one of the gamma Z-box integrals. Our numerical evaluation of the gamma Z box is in agreement within errors with previous reports, albeit somewhat larger in central value, and is within the uncertainty requirements of current experiments.
Rislow, Benjamin C., Contributions from gamma Z box diagrams to parity violating elastic e-p scattering (2011). Physical Review D, 83(11).