Speaker
Description
Spin-1 deep-inelastic scattering targets admit four tensor-polarised structure functions $b_1$–$b_4$ in addition to those of spin-1/2 systems. We present a theoretical framework for the extraction of the tensor-polarised structure functions of general spin-1 systems from the Compton amplitude calculated using the Feynman–Hellmann method, while accounting for the contamination from certain lighter states. The Feynman–Hellmann method relates the energy shift of momentum-projected target correlators under a vector-current perturbation to the forward Compton amplitude, from which the low moments of the structure functions are extracted via the dispersion relations dictated by crossing symmetry. We report lattice QCD calculations of the tensor structure functions of the $\rho$ meson, where there is a theoretical expectation that $b_1 \sim F_1$, and present a pathway for other spin-1 targets.