A puzzle in B(s)0→D(s)()+{π-,K-} decays and extraction of the fs/fd fragmentation fraction

We provide updated predictions for the hadronic decays Bs0-> Ds()+pi- and B0 -> D()+K-. They are based on O(alpha s2) results for the QCD factorization amplitudes at leading power and on recent results for the B(s)-> D(s)() form factors up to order O(Lambda QCD2/mc2) in the heavy-quark expansion. We give quantitative estimates of the matrix elements entering the hadronic decay amplitudes at order O(Lambda QCD/mb) for the first time. Our results are very precise, and uncover a substantial discrepancy between the theory predictions and the experimental measurements. We explore two possibilities for this discrepancy: non-factorizable contributions larger than predicted by the QCD factorization power counting, and contributions beyond the Standard Model. We determine the fs/fd fragmentation fraction for the CDF, D0 and LHCb experiments for both scenarios.