Neutron size from high energy scattering data

TL;DR

This paper examines a proposed gauge boson model aimed at explaining the proton charge radius discrepancy and finds that it conflicts with existing neutron and proton scattering data, challenging the model's validity.

Contribution

The paper critically analyzes a sub-GeV U(1)R gauge boson model and demonstrates its inconsistency with empirical neutron and proton scattering data.

Findings

Neutron and proton mass radii are approximately equal within 2%.

The proposed model's assumptions lead to contradictions with scattering data.

Existing data challenges models modifying quark couplings to explain the radius discrepancy.

Abstract

Alvarado, Aranda, and Bonilla propose a sub-GeV U(1)R gauge boson model to explain the proton charge radius discrepancy. Their model assumes opposite sign U(1)R charge assignments for up and down quarks in the nucleon. I point out that might cause a difference between neutron and proton mass radii that contradicts existing p-p and n-p scattering data. Using existing neutron and proton scattering data I show that the neutron and proton mass radii are equal within about 2%. This constitutes a challenge to models that attempt to explain the discrepancy by modifying the quark couplings.