Quark quasi-Sivers function and quasi-Boer-Mulders function in a spectator diquark model

We compute the leading -twist T-odd quasidistributions of the proton in a spectator model with scalar and axial -vector diquarks: the quasi-Sivers function %'ii,(x,lci;P,) and the quasi-Boer-Mulders function h,'4,14; Pr). We obtain the quark-quark conelators in the four-dimensional Euclidian space by replacing y+ and in' in the light -cone frame with y, and We show by analytical calculation that the results of l'ILT and k derived from the conelators can reduce to the expressions of the corresponding standard T-odd distributions fiix,ki) and hiL(x,ki) in the limit P, > co. The numerical results for these quasidistributions and their first transverse moments for the u and d quarks in different x and P, regions are also 1(1)presented. We find that :7,L,C1) (x, P,) and (x, P,) in the spectator model are fair approximations to the standard ones (within 20%-30%) in the region 0.1 < x < 0.5 when P, > 2.5-3 GeV. This supports the idea of using T-odd quasidistributions to obtain standard distributions in the region P, > 2.5 GeV as fair approximation.