中国物理学会高能物理分会第十一届全国会员代表大会暨学术年会

We study the transverse-momentum-dependent parton distribution functions (TMDs) up to twist-4 in the MIT bag model. Besides the TMDs defined from the quark-quark correlator, we have also calculated those defined via quark-$j$-gluon-quark correlators and four-quark correlators for the first time. All the T-even and T-odd TMDs are computed to the $\alpha_{s}^{1}$ level. Furthermore, we quantitatively evaluate the azimuthal asymmetries in SIDIS resulted from those TMDs. The numerical results show that twist-4 contributions can provide 20 percent corrections to the leading twist correction for the $\langle \sin(\phi-\phi_{S})\rangle_{UT}$ and $\langle \cos(\phi-\phi_{S})\rangle_{LT}$ asymmetries and the twist-3 effects varies between a few percent and 20 percent at low-$Q^{2}$.