Electromagnetic proton-neutron mass difference

TL;DR

This paper evaluates the electromagnetic contribution to the proton-neutron mass difference using the Cottingham formula, incorporating modern experimental data and decomposing the contributions into various terms.

Contribution

It provides a detailed, phenomenologically grounded calculation of the electromagnetic mass difference, including a novel evaluation of the subtraction function from experimental input.

Findings

Quantitative estimate of the electromagnetic proton-neutron mass difference.

Decomposition of the mass difference into Born, inelastic, and subtraction contributions.

Use of up-to-date low-Q^2 data for the Born term evaluation.

Abstract

We discuss the Cottingham formula and evaluate the proton-neutron electromagnetic mass difference exploiting the state-of-the-art phenomenological input. We decompose individual contributions to the mass splitting into Born, inelastic and subtraction terms. We evaluate the subtraction-function contribution from the experimental input only and the Born term accounting for the modern low-$Q^2$ data.