Evidence for the rare decay B+→Ds+π0

The authors have searched for the rare decay B{sup +} {yields} D{sub s}{sup +}{pi}{sup 0}. The analysis is based on a sample of 232 million {Upsilon}(4S) {yields} B{bar B} decays collected with the BABAR detector at the PEP-II e{sup +}e{sup -} storage ring. They find 19.6 signal events, corresponding to a significance of 4.7 {sigma}. The extracted signal yield including statistical and systematic uncertainties is 20.1{sub -6.0-1.5}{sup +6.8+0.4}, and they measure {Beta}(B{sup +} {yields} D{sub s}{sup +}{pi}{sup 0}) = (1.5{sub -0.4}{sup +0.5} {+-} 0.1 {+-} 0.2) x 10{sup -5}, where the first uncertainty is statistical, the second is systematic, and the last is due to the uncertainty on the D{sub s}{sup +} decay and its daughter decay branching fractions.