Observation of the isospin-violating decay Ds*+→Ds+π0

Using data collected with the CLEO II detector, we have observed the isospin-violating decay {ital D}{sub {ital s}}{sup *+}{r_arrow}{ital D}{sup +}{sub {ital s}}{pi}{sup 0}. The decay rate for this mode, relative to the dominant radiative decay, is found to be {Gamma}({ital D}{sub {ital s}}{sup *+}{r_arrow}{ital D}{sup +}{sub {ital s}}{pi}{sup 0}) /{Gamma}({ital D}{sub {ital s}}{sup *+}{r_arrow}{ital D}{sup +}{ital s}{gamma}) =0.062{sub {minus}0.018}{sup +0.020}{plus_minus}0.022. {copyright} {ital 1995} {ital The} {ital American} {ital Physical} {ital Society}.