Longitudinal–transverse double-spin asymmetries in single-inclusive leptoproduction of hadrons

We analyze the longitudinal–transverse double-spin asymmetry in lepton–nucleon collisions where a single hadron is detected in the final state, i.e., ℓ→N↑→hX. This is a subleading-twist observable in collinear factorization, and we look at twist-3 effects in both the transversely polarized nucleon and the unpolarized outgoing hadron. Results are anticipated for this asymmetry from both HERMES and Jefferson Lab Hall A, and it could be measured as well at COMPASS and a future Electron–Ion Collider. We also perform a numerical study of the distribution term, which, when compared to upcoming experimental results, could allow one to learn about the “worm-gear”-type function g˜(x) as well as assess the role of quark–gluon–quark correlations in the initial-state nucleon and twist-3 effects in the fragmenting unpolarized hadron.