First measurement of the CKM angle phi(3) with B-+/--> D(K-S(0)pi(+)pi(-)pi(0)) K-+/- decays

We present the first model-independent measurement of the CKM unitarity triangle angle phi(3) using B-+/--> D(K-S(0)pi(+)pi(-)pi(0)) K-+/- decays, where D indicates either a D-0 or (D) over bar (0) meson. Measurements of the strong-phase difference of the D -> K-S(0)pi(+)pi(-)pi(0) amplitude obtained from CLEO-c data are used as input. This analysis is based on the full Belle data set of 772 x 10(6)B (B) over bar events collected at the gamma(4S) resonance. We obtain phi(3) = (5.7(-8.8)(+10.2)+/- 3.5 +/- 5.7)(degrees) and the suppressed amplitude ratio r(B) = 0.323 +/- 0.147 +/- 0.023 +/- 0.051. Here the first uncertainty is statistical, the second is the experimental systematic, and the third is due to the precision of the strong-phase parameters measured from CLEO-c data. The 95% confidence interval on phi(3) is (-29.7, 109.5)(degrees), which is consistent with the current world average.