I do not get the concepts of the parity change and how do I find the deta (l) for beta decay. Please Help!! Classify the following decays according to their degree of forbiddenness, all ground states decays. 89Sr (5/2+) -> 89Y (1/2-) 26Al (5+) -> 26Mg (2+) 97Zr (1/2+) -> 97Nb (1/2-) What are theirs change in parity and deta (L)? How do you calculate it? Thanks again!