Double-Spin Asymmetry ALTcosϕS in the Lambda Production SIDIS Process Within the Collinear Framework

We study the longitudinal–transverse double-spin asymmetry ALTcosϕS in semi-inclusive deep inelastic scattering (SIDIS) with Λ hyperon production, where a longitudinally polarized beam scatters off a transversely polarized proton target. After integrating over the final-state hadron transverse momentum, the asymmetry contributes in two parts: the convolution of the twist-3 distribution function gT(x) of the proton target with the unpolarized fragmentation function D1(z) for Λ, and the convolution of the transversity distribution h1(x) of the proton target with the twist-3 fragmentation function E˜(z) for Λ. We present predictions for the cosϕS asymmetry in CLAS12, COMPASS, and EicC kinematical regions. The numerical results are sizeable. In particular, E˜(z) dominates in the large-z region, suggesting that measuring the ALTcosϕS asymmetry will offer a promising way to access the twist-3 fragmentation function of the Λ hyperon as well as the flavor separation of the distribution functions.