A new experimental limit for the decay k+ → π+γγ

A search for K+ → π+γ, π+γγ, π+γγγ was made detecting pions from stopped kaons in the kinetic energy region between 117 MeV and 127 MeV. New limits of 1.4 x 10-6 and 1.0 x 10-4 for the branching ratio were obtained assuming a phase-space spectrum on the pion energy. The first limit also applies to another process K+ → π+ + a, where a is a light meson with mass smaller than 100 MeV/c2 and decays into nγ's with lifetime less than 10-9 s. (orig.)