The transverse-spin asymmetry $A_{UUT}^{\sin {\varphi }_{S_{\Lambda }}}$ in $\Lambda$ production in SIDIS within the collinear framework

Abstract

We investigate the transverse-spin asymmetry $A_{UUT}^{\sin {\varphi }_{S_{\Lambda }}}$ for transversely polarized $\Lambda$ production in semi-inclusive deep inelastic scattering with an unpolarized electron beam and an unpolarized nucleon target. The spin-dependent asymmetry is sensitive to the twist-3 T-odd quark-gluon-quark fragmentation function ${\tilde{D}}_T$, which describes the correlation between an unpolarized fragmenting quark and the transverse polarization of the produced hadron. We calculate ${\tilde{D}}_T$ of the $\Lambda$ hyperon within a diquark model and investigate its contribution to the asymmetry. We determine the model parameters by fitting the fragmentation functions $D_1$ and $G_1$ to the DSV parametrization. Using the numerical results of the model and the available parametrization of the unpolarized parton distribution function $f_1$, we predict the asymmetry in the electroproduction of the $\Lambda$ hyperon in the kinematic regions of the EIC and the EicC. We also examine the impact of including the strange-quark contribution on the transverse-spin asymmetry. In our phenomenological analysis, we include the QCD evolution of the parton distribution function $f_1$ and the fragmentation function ${\tilde{D}}_T$. The results show that the asymmetry is sizable and can be significantly modified by the strange-quark contribution.

Comments: 11 pages, 7 figures