First precise test of flavor symmetries in D decays

So far first order SU(3) breaking corrections have been estimated roughly in D meson decay amplitudes. U spin is an SU(2) subgroup of SU(3). We study U spin breaking in these amplitudes up to third order and first order isospin breaking. A high precision amplitude relation is obtained whose violation would indicate physics beyond the standard model.An experimental precision around 0.3% in this amplitude relation has been achieved largley due to an experiment at the LHC.