| Abstract: |
At present we are at the confluence of two exciting developments in the field of muon capture. For the first time, experiments on hydrogen and the lightest nuclei are approaching sub-percent precision based on the novel active target technique developed by our collaboration, surpassing the precision of earlier data by about an order of magnitude. At the same time, effective field theories have been systematically constructed to calculate electro-weak observables for the nucleon and basic few-body systems from first principles. The MuCap experiment clarifies a long-standing puzzle about the pseudoscalar coupling of the proton and provides a basic test of QCD symmetries. In the case of deuterium, the MuSun experiment will allow a comprehensive test of the theoretical description of weak few-body reactions and will determine a low energy constant, which is critical for the calculation of related astrophysics reactions of fundamental interest. |
