Electromagnetic corrections in eta --> 3 pi decays
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 e2(mu-md) disregarded so far are not negligible compared to other contributions of order e2 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.
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