B→D*0 and Bs→D*s0 form factors from QCD light-cone sum rules

Abstract

We present the first application of QCD light-cone sum rules (LCSRs) with B(s)-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 BD decays. The BD0 form factors are calculated in both scenarios, also taking into account the large total width of D0(2300). Furthermore, we calculate the BsDs0 form factors, considering in this case only the one-resonance scenario with Ds0(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 BD0 and Bs Ds0 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).