Measurement of CP asymmetries and branching-fraction ratios for B ± → DK ± and Dπ ± with D → K S 0 $$ {K}_{\textrm{S}}^0 $$ K ± π ∓ using Belle and Belle II data

Abstract We measure CP asymmetries and branching-fraction ratios for B ± → DK ± and Dπ ± decays with D → K S 0 $$ {K}_{\textrm{S}}^0 $$ K ± π ∓, where D is a superposition of D 0 and D ¯ $$ \overline{D} $$ 0. We use the full data set of the Belle experiment, containing 772 × 106 B B ¯ $$ B\overline{B} $$ pairs, and data from the Belle II experiment, containing 387 × 106 B B ¯ $$ B\overline{B} $$ pairs, both collected in electron-positron collisions at the Υ(4S) resonance. Our results provide model-independent information on the unitarity triangle angle ϕ 3.