Electromagnetic corrections to gamma pi(+/-)->pi(0)pi(+/-) - art. no. 094009

The amplitude for the anomalous transitions gamma pi (+/-) --> pi (o)pi (+/ -) is analyzed within chiral perturbation theory including electromagnetic interactions. The presence of a t-channel one-photon exchange contribution induces sizable O(e(2)) corrections which enhance the cross section in the threshold region and bring the theoretical prediction into agreement with a vailable data. In the case of the crossed reaction gamma pi (o) --> pi (+)p i (-), the same contribution appears in the s channel and its effects are s mall.