Coulomb-Nuclear Interference in polarized pA scattering

TL;DR

This paper investigates the Coulomb-nuclear interference effects in polarized proton-nucleus scattering, focusing on how short-range hadronic interactions modify electromagnetic interactions and influence single-spin asymmetries at small angles.

Contribution

It introduces a novel approach by treating short-range hadronic interactions as corrections to electromagnetic interactions, affecting Coulomb-nuclear interference analysis.

Findings

Short-range hadronic interactions significantly alter Coulomb phase calculations.

The approach explains the unusual t dependence of single-spin asymmetry observed in experiments.

Coulomb-nuclear interference is crucial for understanding spin asymmetries at small angles.

Abstract

We made the first attempt to understand the observed unusual t dependence of single-spin asymmetry observed in the HJET experiment at RHIC. Usually, the interaction of hadrons is presented as a long-range Coulomb interaction and a short-range strong interaction with Coulomb corrections. Such a division gives rise to a Coulomb phase of the hadronic term. Conversely, here we consider short-range hadronic interaction as a correction to the long-range electromagnetic term, i.e., we treat it as an absorptive correction. This significantly affects the Coulomb-nuclear interference, which is a source of single-spin azimuthal asymmetry at small angles.