Light-Cone Wavefunction Representations of Sivers and Boer-Mulders Distribution Functions

TL;DR

This paper derives light-cone wavefunction representations for the Sivers and Boer-Mulders distribution functions, highlighting the role of complex phases induced by final-state interactions, and compares model-specific results.

Contribution

It introduces a method to represent Sivers and Boer-Mulders functions via light-cone wavefunctions with complex phases, providing explicit calculations in diquark models.

Findings

Sivers function has opposite signs with a factor of 3 difference in magnitude between models.

Boer-Mulders function has the same sign and magnitude in both models.

Results are explained through properties of light-cone wavefunction representations.

Abstract

We find the light-cone wavefunction representations of the Sivers and Boer-Mulders distribution functions. A necessary condition for the existence of these representations is that the light-cone wavefunctions have complex phases. We induce the complex phases by incorporating the final-state interactions into the light-cone wavefunctions. For the scalar and axial-vector diquark models for nucleon, we calculate explicitly the Sivers and Boer-Mulders distribution functions from the light-cone wavefunction representations. We obtain the results that the Sivers distribution function has the opposite signs with the factor 3 difference in magnitude for the two models, whereas the Boer-Mulders distribution function has the same sign and magnitude. We can understand these results from the properties of the light-cone wavefunction representations of the Sivers and Boer-Mulders distribution functions.