Single Spin Effects in Collisions of Hadrons and Heavy Ions at High Energy

TL;DR

This paper proposes a new mechanism involving quark chromomagnetic interactions to explain single spin effects observed in high-energy hadron and heavy ion collisions, aligning well with experimental data.

Contribution

It introduces a novel model based on quark chromomagnetic moments and spin precession to explain single spin asymmetries in various collision types.

Findings

Model explains oscillations of spin observables with Feynman xF.

Data supports a large negative anomalous chromomagnetic moment of quarks.

Predictions align with experimental results in heavy ion collisions.

Abstract

Experimental data on transverse single-spin asymmetry, hyperon polarization and vector meson alignment in h+h, h+A and A+A-collisions have been analyzed. A new mechanism for the origin of single spin effects is proposed, which takes into account the interaction of massive constituent quarks via their chromomagnetic moment with an effective inhomogeneous chromomagnetic field of strings, produced after the initial color exchange. Quark spin precession in the color field is taken into account, which can be the reason for an oscillation of the single spin observables as a function of Feynman $x_{F}$ and its energy dependence. The model predictions are compared with the experimental data, in particular with the heavy ion collision data. The data are consistent with a large negative anomalous chromomagnetic moment of the constituent quarks which is predicted in the instanton model.