Leading Isospin Breaking effects in nucleon and $\Delta$ masses

TL;DR

This paper presents a lattice QCD+QED calculation of the leading isospin breaking effects on nucleon and Delta resonance masses, accounting for electromagnetic and quark mass difference contributions.

Contribution

It provides the first lattice computation of leading isospin breaking corrections to baryon masses including both QED and quark mass difference effects.

Findings

Quantifies electromagnetic contributions to nucleon and Delta masses.

Determines quark mass difference effects on baryon mass splittings.

Offers insights into isospin symmetry breaking in QCD.

Abstract

We present a lattice calculation of the leading corrections to the masses of nucleons and $\Delta$ resonances. These are obtained in QCD+QED at $1$st order in the Isospin Breaking parameters $\alpha_{EM}$, the electromagnetic coupling, and $\frac{{\hat{m}}_d - {\hat{m}}_u}{\Lambda_{QCD}}$, coming from the mass difference between $u$ and $d$ quarks.