Beam single spin asymmetry $A_{LU}^{\sin {\varphi }_R}$ of the dihadron production in SIDIS process

Abstract

We study the longitudinal beam single-spin asymmetry $A_{LU}^{\sin {\varphi }_R}$ of dihadron production in semi-inclusive deep inelastic scattering process with a polarized electron beam scattering off an unpolarized proton target. The asymmetry arises from the convolutions of twist-3 PDF $e(x)$ and twist-2 DiFF $H_1^{\sphericalangle }$ as well as twist-2 PDF $f_1(x)$ and twist-3 DiFF ${\tilde{G}}^{\sphericalangle }$. Using the spectator model calculations for the twist-3 PDF $e(x)$, the DiFFs $D_1,H_1^{\sphericalangle }$, and ${\tilde{G}}^{\sphericalangle }$, we estimate the BSA $A_{LU}^{\sin {\varphi }_R}$ at the kinematical configuration of CLAS and CLAS12. We find good agreement with $z$- and $M_h$-dependencies data, though $x$- and $Q^2$- dependencies show discrepancies. We include DGLAP evolution of $e(x)$ and provide predictions for COMPASS, EIC, and EicC. The negligible contribution from $f_1(x)\otimes {\tilde{G}}^{\sphericalangle }$ supports the Wandzura-Wilczek approximation, while our results highlight the importance of QCD evolution in twist-3 PDF analyses.

Comments: 15 pages