June 2022
Strong interaction in view
“As a theoretical particle physicist, I try to predict the properties of certain particles as precisely as possible. Through comparison with the corresponding experiments, we want to find out where the standard model has weaknesses. Many experimental results today are only subject to very small uncertainties. The aim is to be able to keep pace with this in our theoretical predictions.
We are particularly interested in the strong interaction because it is the most complicated to calculate - we can no longer do this with pen and paper. The strong interaction binds quarks together within the atomic nucleus and is mediated by gluons. In order to predict their dynamics, we need supercomputers and have to simplify the real world. For this purpose, we use lattice field theory.
©: Angelika Stehle
In the first step, we restrict ourselves to a finite section of reality: we consider a cube that must be large enough so that bound states of quarks and gluons, for example pions, protons and neutrons, can exist in it without their properties being noticeably affected by the fact that the cube is not infinitely large. We then place individual lattice points inside the cube.
Now we simulate many different configurations of how the gluons interact with themselves and the quarks on the lattice points. Hundreds to thousands of such snapshots form an ensemble. We use the same set of 25 ensembles in almost all projects in Mainz: it is our toolbox, so to speak, and we can use it to calculate the anomalous magnetic moment of the muon, for example.
A new experimental value caused quite a stir last year, as the current theoretical value deviates significantly. With new innovative lattice calculations, which have only been possible for a few years, we want to continue to refine our predictions. This is only possible within the framework of a large network and makes research very exciting in these times.”
Dr. Simon Kuberski has been a postdoc in Professor Hartmut Wittig's group since October 2020. What fascinates him most about his research is how it is possible to describe a great deal of physics with just a few basic equations and parameters - so simple on the one hand and so complex on the other.