Speaker
Description
Understanding the nuclear structure, for example by means of form factors, is a key
prerequisite in the search for new physics. A prominent role is played by the famous
proton radius puzzle, whose solution requires precise knowledge of the electromag-
netic factors at small momentum transfer. But also other current investigations
rely on detailed knowledge of nuclear, and hence, nucleon structure, such as high
precision determinations of the weak mixing angle or next-generation neutrino
experiments. Due to the hadronic nature of nucleons, a perturbative treatment
of the strong interaction is not possible and phenomenological approaches typi-
cally rely strongly on experimental data. Lattice QCD, in contrast, can provide
non-perturbative, theory predictions of hadronic quantities from first-principles,
making it an important tool to investigate nucleon form factors and compare the
results with experimental findings. In this talk we will take a closer look at the
calculations of the electromagnetic form factors conducted by the Mainz Lattice
QCD group. First, the results of the 2024 analysis on the isovector and isoscalar
contributions to the electromagnetic form factors will be discussed, including a
comparison of various lattice results for the proton radii. Second, an outlook will
be provided, showing how the efforts towards obtaining the flavor decomposition
of electromagnetic form factors including strange and charm quark effects are pro-
ceeding.