Quark model of nucleon based on an analogy with polaron

TL;DR

This paper proposes an analogy between polaron physics and non-perturbative QCD to model nucleons, leading to accurate predictions of nucleon properties and insights into quark contributions.

Contribution

It introduces a novel polaron/QCD correspondence that yields quantitative predictions for nucleon mass and sigma term, bridging solid state physics and strong interaction theory.

Findings

Predicted nucleon mass and sigma term match experimental data.

Constituent quark accounts for one-third of nucleon mass, consistent with lattice results.

Provides a new physical perspective on non-perturbative QCD phenomena.

Abstract

We demonstrate that the polaron theory from solid state physics can serve as an interesting analogue model for non-perturbative QCD, at least in the description of nucleons and related low-energy physics of strong interactions. By drawing explicit analogies between polaron physics, arising for an electron moving in an ionic crystal, and physics of pion-nucleon interactions, certain rules for the "polaron/QCD correspondence" are proposed. In polaron theory, the effective fermion mass as a function of the coupling constant is known both in the weak and strong coupling limits. The conjectured "polaron/QCD correspondence" translates these results into strong interactions. It is then shown how application of these rules leads to unexpectedly good quantitative predictions for the nucleon mass and the pion-nucleon sigma term. The polaron approach also predicts that the quark degrees of freedom in the form of the constituent quark account for one-third of the nucleon mass, consistent with lattice predictions. We discuss possible physical reasons underlying the observed quantitative similarity between polaron physics and non-perturbative QCD.