Observation of the Doubly Cabibbo-Suppressed Decay D-s(+)-> K+K+pi(-)

Abstract

We report the first observation of the doubly Cabibbo-suppressed decay D-s(+)-> K+K+pi(-) using 605 fb(-1) of data collected with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. The branching ratio with respect to its Cabibbo-favored counterpart B(D-s(+)-> K+K+pi(-))/B(D-s(+)-> K+K-pi(+)) is (0.229 +/- 0.028 +/- 0.012)%, where the first uncertainty is statistical and the second is systematic. We also report a significantly improved measurement of the doubly Cabibbo-suppressed decay D+-> K+pi(+)pi(-), with a branching ratio B(D+-> K+pi(+)pi(-))/B(D+-> K-pi(+)pi(+))=(0.569 +/- 0.018 +/- 0.014)%.