Principal Investigator: Kálmán Szabó, University of Wuppertal and Forschungszentrum Jülich, Germany
HPC Platform used: JUWELS of JSC, SuperMUC and SuperMUC-NG of LRZ
Local Project ID: chfz04, pn56bu
Today, large-scale computations of lattice QCD can easily reach a precision of 1% and below—a level at which it is necessary to factor in isospin breaking arising from 1. the presence of the electromagnetic interaction, and 2. the mass difference between up and down quarks. The most prominent consequence of these effects is the mass difference of the neutron and the proton as its numerical value influences the stability of matter: were this difference a bit different from what is measured in experiments, matter would become unstable so that no atoms, molecules and more complex structures could be formed. It was successfully demonstrated that this mass difference can be computed in a common lattice framework of a full QCD + QED calculation.