B→D0∗ and Bs→Ds0∗ form factors from QCD light-cone sum rules

We present the first application of QCD light-cone sum rules (LCSRs) with B <inf>(s)</inf>-meson distribution amplitudes to the B(s)→D(s)0∗ form factors, where D(s)0∗ is a charmed scalar meson. We consider two scenarios for the D0∗ spectrum. In the first one, we follow the Particle Data Group and consider a single broad resonance D0∗(2300) . In the second one, we assume the existence of two scalar resonances, D0∗(2105) and D0∗(2451) , as follows from a recent theoretically motivated analysis of B → Dππ decays. The B→D0∗ form factors are calculated in both scenarios, also taking into account the large total width of D0∗(2300) . Furthermore, we calculate the Bs→Ds0∗ form factors, considering in this case only the one-resonance scenario with D<inf>s0</inf>(2317). In this LCSRs calculation, the c-quark mass is kept finite and the s-quark mass is taken into account. We also include contributions of the two- and three-particle distribution amplitudes up to twist-four. Our predictions for semileptonic B→D0∗ℓνℓ and Bs→Ds0∗ℓνℓ branching ratios are compared with the available data and HQET-based predictions. As a byproduct, we also obtain the D0∗ - and Ds0∗ -meson decay constants and predict the lepton flavour universality ratios R(D0∗) and R(Ds0∗) .