Twist-3 T-odd fragmentation functions G⊥ and G˜⊥ in a spectator model

We present a calculation of the twist-3 T-odd chiral-even fragmentation functions G⊥G⊥ and G˜⊥ using a spectator model. We consider the effect gluon exchange to calculate all necessary one-loop diagrams for the quark–quark and quark–gluon–quark correlation functions. We find that the gluon loops corrections generate non-zero contribution to these two fragmentation function. We numerically calculate their half-kTkT moments by integrating over the transverse momentum and also verify the equation of motion relation among G⊥G⊥, G˜⊥ and the Collins function.