Sivers function of sea quarks in the light-cone model

Abstract

We calculate the Sivers function of u¯ and d¯ quarks using the overlap representation within the light-cone formalism. The light-cone wave functions of the proton are obtained in terms of the |q¯qB〉 Fock states motivated by the meson-baryon fluctuation model. We consider the final-state interaction at the level of one gluon exchange. In a simplified scenario, the Sivers function of u¯ and d¯ can be expressed as the convolution of the Sivers function of the pion inside the proton and the unpolarized distribution of q¯ inside the pion. The model parameters are fixed by fitting the unpolarized sea quark distributions to the known parameterizations. We present the numerical results for f1⊥u¯/p(x,kT2) and f1⊥d¯/p(x,kT2). The first transverse moment of the sea quark Sivers functions in our model are find to be negative and the magnitude is about 0.004 at most.