Extraction of finite-energy contributions to the Sivers asymmetry from the analysis of exclusive proton-proton scattering

TL;DR

This paper investigates how scalar and spin-orbit rescattering effects contribute to the Sivers asymmetry in proton-proton collisions at moderate energies, using an extended Glauber model fitted to elastic scattering data.

Contribution

It introduces an ultrarelativistic Glauber formalism to connect elastic scattering data with inclusive asymmetries, highlighting a potential higher-twist contribution to the Sivers effect.

Findings

Rescattering interactions produce a significant nonzero analyzing power in inclusive processes.

Phenomenological interactions explain the nonzero analyzing power observed in elastic scattering.

Potential higher-twist effects are relevant for understanding the Sivers asymmetry.

Abstract

I study the effect of scalar and spin-orbit rescattering terms, in the production of a nonzero Sivers-like asymmetry in proton-proton collisions (nclusive production and Drell-Yan) at moderate center of mass energies $\sqrt{s}$ $<$ 15 GeV and transverse momentum up to 3 GeV/c. An ultrarelativistic generalization of the Glauber formalism is here used to (i) fit the scalar and spin-orbit interaction terms on proton-proton elastic scattering data, including analyzing power, (ii) transfer such information to inclusive proton-proton scattering. It is shown that the phenomenological interactions responsible for the nonzero analyzing power in proton-proton elastic scattering produce a relevant nonzero analyzing power in inclusive processes associated with proton-proton collisions. This could represent a relevant (possibly higher-twist) contribution to the Sivers asymmetry.