Measurement of the branching fractions of (B)over-bar → D(*)K-K(*)0(S) and (B)over-bar → D(*)D-s decays at Belle II

We present measurements of the branching fractions of eight (B) over bar -> (D(*)+K-K()*()0)((S)), B- -> D-(*(K-K()-K-)0*()0)((S)) decay channels. The results are based on data from SuperKEKB electron-positron collisions at the Upsilon(4S) resonance collected with the Belle II detector, corresponding to an integrated luminosity of 362 fb(-1). The event yields are extracted from fits to the distributions of the difference between expected and observed B meson energy, and are efficiency-corrected as a function of m((K-K()*()0)((S))) and m(D-(*K-)(()*()0)((S))) in order to avoid dependence on the decay model. These results include the first observation of (B) over bar (0) -> (D+K-KS0), B- -> D*(K-KS0)-K-0, and (B) over bar (0) -> D*(+K-KS0) decays and a significant improvement in the precision of the other channels compared to previous measurements. The helicity-angle distributions and the invariant mass distributions of the (K-K()*()0)((S)) systems are compatible with quasi-two-body decays via a resonant transition with spin-parity J(P) = 1(-) for the (K-KS0) systems and J(P) = 1(+) for the K-K*(0) systems. We also present measurements of the branching fractions of four (B) over bar (0) -> D-(*D-)+(s)-, B- -> D-(*D-)0(s)- decay channels with a precision compatible to the current world averages.