Etaprime and Eta Mesons with Connection to Anomalous Glue

TL;DR

This paper reviews eta and etaprime meson physics as probes of gluon dynamics in low-energy QCD, covering production mechanisms, medium modifications, bound states, and decay measurements, highlighting recent experimental and theoretical developments.

Contribution

It synthesizes recent experimental data and theoretical insights on eta and etaprime mesons, emphasizing their role in understanding gluon interactions and low-energy QCD phenomena.

Findings

Production mechanisms of eta and etaprime mesons in proton-nucleon collisions.

Observation of eta and etaprime effective mass shifts in nuclear media.

Searches for eta and etaprime bound states in nuclei.

Abstract

We review the present understanding of etaprime and eta meson physics and these mesons as a probe of gluon dynamics in low-energy QCD. Recent highlights include the production mechanism of eta and etaprime mesons in proton-nucleon collisions from threshold to high-energy, the etaprime effective mass shift in the nuclear medium, searches for possible eta and etaprime bound states in nuclei as well as precision measurements of eta decays as a probe of light-quark masses. We discuss recent experimental data, theoretical interpretation of the different measurements and the open questions and challenges for future investigation.