Conservation Laws in the Isotopic Spin Space and Their Violation by the Electromagnetic Interaction

The SIGMA /sup +/- SIGMA /sup -/ mass difference and the electromagnetic correction on the DELTA I = 1/2 law for non-leptonic hyperon snd K-meson decays are discussed, based on the assumption of charge independence for strong interactions. Simple calculation for the two phenomena reveals the difficulty that larger electromagnetic effects are needed. Various approximate conservation laws in the isotopic spin space and their implications for the understanding of non-leptonic decays are likewise discussed. (auth)