Search for CP violation in the decays D+ → KSπ+ and D+ → KSK+ -: art. no. 041602

A high-statistics sample of photoproduced charm from the FOCUS experiment has been used to search for direct CP violation in the decay rates for D+ --> K(S)pi(+) and D+ --> KSK+. We have measured the following asymmetry parameters relative to D+ --> K- pi(+) pi(+): A(CP)(K(S)pi(+)) = (-1.6 +/- 1.5 +/- 0.9)%, A(CP)(KSK+) = (+6.9 +/- 6.0 +/- 1.5)%, and A(CP)(KSK+) = (+7.1 +/- 6.1 +/- 1.2)% relative to D+ --> K(S)pi(+). We have also measured the relative branching ratios and found Gamma(D+ --> (K) over bar K-0(+))/Gamma(D+ --> (K) over bar (0)pi(+))/Gamma(D+ --> K- pi(+) pi(+)) = (30.60 +/- 0.46 +/- 0.32)%, Gamma(D+ --> (K) over bar K-0(+))/Gamma(D+ --> K- pi(+) pi(+)) = (6.04 +/- 0.35 +/- 0.30)%, and Gamma(D+ --> (K) over bar K-0(-))/Gamma(D+ --> (K) over bar (0)pi(+)) = (19.96 +/- 1.19 +/- 0.96)%.