Testing lorentz symmetry using chiral perturbation theory

We consider the low-energy effects of a selected set of Lorentz- and CPT-violating quark and gluon operators by deriving the corresponding chiral effective lagrangian. Using this effective lagrangian, low-energy hadronic observables can be calculated. We apply this to magnetometer experiments and derive the best bounds on some of the Lorentz-violating coefficients. We point out that progress can be made by studying the nucleon-nucleon potential, and by considering storage-ring experiments for deuterons and other light nuclei.Portuguese Foundation for Science and Technology (FCT) [SFRH/BPD/101403/2014]program POPH/FS

Question of Lorentz invariance in muon decay

Possibilities to test the Lorentz invariance of the weak interaction in muon decay are considered. We derive the general Lorentz-violating muon-decay rate and discuss measurements of the directional and boost dependence of the Michel parameters and of the muon lifetime as function of absolute velocity. The current data on the muon lifetime at rest and in flight appear to be inconsistent. We make suggestions for dedicated reanalyses of the pertinent data and for future experiments. An interpretation in the Lorentz-violating Standard Model Extension is given