High Energy Physics Group

Lattice QCD & Flavor Physics

The Lattice QCD research program at the University is focused on calculations that support experimental physics (mainly, but not exclusively) at the Intensity frontier, where new physics searches proceed by comparing precision measurement with the Standard Model theory. A discrepancy between the two would then be an indirect observation of new physics. In order to know the extent to which Intensity frontier measurements are (in)compatible with Standard Model theory, one needs theoretical predictions with completely quantified and reliably estimated uncertainties. However, many observables receive important contributions from nonperturbative QCD effects, which are notoriously difficult to calculate reliably. When the resulting theory errors are larger than experimental uncertainties, they limit the potential impact of the corresponding measurements.

Lattice QCD is a general purpose tool for calculating such nonperturbative effects, and recent years have brought enormous progress, improving the accuracy and reliability of lattice calculations. We have produced the most precise results to date for a number of hadronic matrix elements relevant for weak kaon, D- and B-meson processes, with significant reductions in the quoted uncertainties compared to previous results. We plan to build on and extend this work with projects that include new calculations of similar weak hadronic matrix elements with even better precision and of quantities relevant for muon g-2 and neutrino experiments, and precision measurements of Higgs decay rates.