Speaker
Description
The dominant contribution to the theoretical uncertainty in the extracted weak parameters of the Standard Model comes from the hadronic uncertainties in the electroweak box diagrams, i.e. $\gamma-W^\pm/Z$ exchange diagrams. A dispersive analysis relates the box diagrams to the parity-odd structure function, $F_3$, for which the experimental data either do not exist or belong to a separate isospin channel. Therefore a first-principles calculation of $F_3$ is highly desirable.
In this contribution, I report on the QCDSF Collaboration's calculation of the moments of the $F_3^{\gamma Z}$ structure function from the forward Compton amplitude at the SU(3) symmetric point. We focus on the first moment of $F_3^{\gamma Z}$ for a range of $Q^2$ values. We discuss the implications of our results for the electroweak box diagrams along with the possibility of a determination of the strong coupling constant via the Gross-Llewellyn Smith sum rule.
