Electromagnetic effects in eta --> 3 pi
arXiv:0910.0210
Abstract
We re-evaluate the electromagnetic corrections to eta --> 3 pi decays at next-to-leading order in the chiral expansion, arguing that effects of order e^2(m_d-m_u) disregarded so far are not negligible compared to other contributions of order e^2 times a light quark mass. Despite the appearance of the Coulomb pole in eta --> pi+ pi- pi0 and cusps in eta --> 3 pi0, the overall corrections remain small.
9 pages, 5 figures, talk given at 6th International Workshop on Chiral Dynamics, Bern, Switzerland, July 6-10, 2009