This proposal funds the research activities of Assistant Professor Jack Laiho at Syracuse University. Laiho's research focuses on precision studies of the interactions of quarks via the strong and weak nuclear forces. These forces are a part of the enormously successful Standard Model of particle physics. In order to compare the predictions of the Standard Model with experimental observations large-scale supercomputer calculations are required to correctly account for the effects of the strong nuclear force using an approach called Lattice Quantum Chromodynamics (QCD). Theoretical predictions of the Standard Model are compared with experimental results obtained from particle accelerator experiments, thus testing our understanding of the laws of nature. So far, good agreement has been found. While it is satisfying that the current framework describes matter and its interactions so well, it is known from cosmology that there is physics not accounted for within the Standard Model. The discovery of discrepancies between the Standard Model predictions and experiments done at particle colliders would be very exciting, as such results could lead to an understanding of the mysteries that are not explained in the current framework, including why there is as much matter in the universe as there is. A broader impact of this research is that the Lattice QCD ensembles used by the PIs are made publicly available and are used by other researchers studying quark interactions throughout the world. Additionally, knowledge of computational methods and problem solving skills needed to perform research in lattice field theory are useful assets for graduate students, whether they continue in academic research positions or get jobs in the private sector.
Laiho's research focuses on calculations using Lattice QCD that are needed to maximize the impact of high-energy particle physics experiments. This includes lattice calculations of heavy-light and light-light weak matrix elements, quantities where one needs to control the effects of non-perturbative QCD. This work makes use of high performance computing facilities throughout the US, and is used for calculations of Standard Model predictions that are needed for comparisons with experimental observations as part of the search for new physics. Laiho also has an interest in applying lattice methods to the study of quantum gravity to try to determine whether or not a quantum field theory of gravity is renormalizable when formulated nonperturbatively. The Lattice QCD calculations funded by this grant are essential to make best use of the existing and planned experimental facilities including LHCb and Belle II. They can help to uncover new physics beyond the Standard Model, and they provide insight into the workings of the strong nuclear force and quark interactions. The research on gravity might lead to an understanding of how to handle another nontrivial theory using lattice methods in the non-perturbative regime.