Hadronic contributions to the muon (g-2) from lattice QCD and searches for new physics beyond the Standard Model – gm2lattice

One of the most promising quantities for the search of physics beyond the Standard Model is the anomalous magnetic moment of the muon. A discrepancy of about 3.5 standard deviations is observed between the theory and its experimental determination. New experiments aim at reducing the error by a factor of 4 and a similar effort, to reduce the theory error, is highly desired. The latter is completely dominated by hadronic uncertainties. The non-perturbative nature of the strong interaction forbids the use of standard techniques based on perturbation theory and Lattice QCD, which relies on a rigorous definition of the path integral well suited to massively parallel numerical simulations, is a promising tool. We plan to compute the hadronic light-by-light contribution to the muon anomaly, which dominates the theory error. This is of major importance to fully benefit from the new experimental results expected in the next few years, and could lead to the first unambiguous sign of new physics