One of the central goals of particle physics is to test how well the Standard Model describes nature. A particularly sensitive way to do this is through extremely precise measurements of particles’ magnetic properties. The muon, a heavier cousin of the electron, behaves like a tiny magnet. Experiments have measured this magnetic behavior, known as the muon magnetic moment, with stunning accuracy. To fully exploit this achievement, theorists must match this precision in their calculations. Only then can even tiny deviations reveal the presence of new, yet-undiscovered particles or interactions.
A key part of the theoretical prediction involves understanding how the strong force influences the muon. This contribution is called the hadronic vacuum polarization (HVP). It can only be calculated reliably using lattice quantum chromodynamics (lattice QCD), a numerical approach that simulates the strong force by representing space and time on a grid. However, these simulations are extremely demanding: achieving higher precision requires much finer and larger grids, which rapidly increases the computational effort needed to obtain reliable results.
The HiCoLat project set out to address this challenge. Its objective was to develop and apply improved computational methods that reduce noise and control systematic uncertainties in high-resolution lattice QCD simulations. With these enhanced tools, the project aimed to produce a more precise and reliable determination of the HVP contribution to the muon magnetic moment. In addition, the project explored how the same techniques could benefit other areas of particle physics, including studies of heavy quarks that play a role in current searches for physics beyond the Standard Model.
