Using Genetic Programming Event Selection The FOCUS Collaboration

We apply a genetic programming technique to search for the doubly Cabibbo suppressed decays Λc → pKπ− and Ds → KKπ−. We normalize these decays to their Cabibbo favored partners and find BR(Λc → pKπ)/BR(Λc → pKπ+) = (0.05 ± 0.26 ± 0.02)% and BR(Ds → KKπ)/BR(Ds → KKπ+) = (0.52 ± 0.17 ± 0.11)% where the first errors are statistical and the second are systematic. Expressed as 90% confidence levels (CL), we find < 0.46% and < 0.78% respectively. This is the first successful use of genetic programming in a high energy physics data analysis.