Quark Sivers Function at Small-$x$: Leading contribution from the Spin-Dependent Odderon

TL;DR

This paper calculates the leading contribution to the quark Sivers function at small-$x$ using high energy scattering and operator formalism, highlighting the role of the spin-dependent odderon, and provides a small-$x$ estimate within the diquark model.

Contribution

It introduces a novel calculation of the dominant small-$x$ contribution to the quark Sivers function from the spin-dependent odderon, using an operator formalism and diquark model.

Findings

Dominant contribution from the spin-dependent odderon identified.

Agreement with previous results by Dong, Zhen, and Zhou.

Small-$x$ estimate of the Sivers function obtained.

Abstract

We present the calculation of the leading contribution to the quark Sivers function at small-Bjorken $x$. This calculation uses the high energy scattering approximation and operator formalism developed by Kovchegov and Sievert to obtain a dominant contribution to the quark Sivers function coming from the spin-dependent odderon, in agreement with the results of Dong, Zhen, and Zhou. We then calculate this dominant contribution in the diquark model of the proton to obtain a small-$x$ estimate for the Sivers function.