Study of K^0 \to pi^- e^+ nu_e e^+ e^- in chiral perturbation theory

K. Tsuji, T. Sato

K^0 \to pi^- e^+ nu_e e^+ e^- decay is studied up to the next-to-leading order O^4 in chiral perturbation theory. It is found that the O^4 terms appreciably modifiy the shape of th…