Branching fractions for D0→K+K- and D0→π+π-, and a search for CP violation in D0 decays

Using the large hadroproduced charm sample collected in experiment E791 at Fermilab, we have measured ratios of branching fractions for the two-body singly-Cabibbo-suppres sed charged decays of the D-0* Gamma(D-0 --> K+ K-)/Gamma(D0 --> K- pi(+)) = 0.109 +/- 0.003 +/- 0.003 Gamma(D-0--> K+K-)/Gamma(D0 --> K-K+) = 0.040 +/- 0.002 +/- 0.003, and Gamma(D0 --> K+K-)/Gamma(D-0 --> pi(+)pi(-)) = 2.75 +/- 0.15 +/- 0.16. We have looked for differences in the decay rates of D-0 and (D) over bar(-0) to the CP eigenstates K+K- and pi(+)pi(-), and have measured the CP asymmetry parameters A(CP)(K+ K-) = -0.010 +/- 0.049 +/- 0.012 and A(CP)(pi(+) pi(-)) = -0.049 +/- 0.078 +/- 0.030, both consistent with zero. (C) 1998 Elsevier Science B.V.