We discuss the determination of deep-inelastic hadron structure in lattice QCD. By using a fictitious heavy-quark, direct calculations of the Compton scattering tensor can be performed in Euclidean space that allow the extraction of the moments of structure functions. This overcomes issues of operator mixing and renormalization that have so far prohibited lattice computations of higher moments. This approach is especially suitable for the study of the twist-two contributions to isovector quark distributions, which is practical with current computing resources. While we focus on the isovector unpolarized distribution, our method is equally applicable to other quark distributions and to generalized parton distributions. By looking at matrix elements such as $⟨{\pi }^{\pm }|T[V^{\mu }(x)A^{\nu }(0)]|0⟩$ (where $V^{\mu }$ and $A^{\nu }$ are vector and axial-vector heavy-light currents) within the same formalism, moments of meson distribution amplitudes can also be extracted.

• Received 21 July 2005

DOI:https://doi.org/10.1103/PhysRevD.73.014501