D-meson decay constants and a check of factorization in non-leptonic B-decays

A bstract We compute the vector meson decay constants from the simulation of twisted mass QCD on the lattice with N f = 2 dynamical quarks. When combining these values with the pseudoscalar D ( s ) -meson decay constants, we were able (i) to show that the heavy quark spin symmetry breaking effects with the charm quark are large, , and (ii) to check the factorization approximation in a few specific B -meson non-leptonic decay modes. Besides our main results, , and , other phenomenologically interesting results of this paper are: , , and . Finally, we correct the value for B ( B 0 → D + π − ) quoted by PDG, and find B ( B 0 → D + π − ) = (7.8 ± 1.4) × 10 −7 . Alternatively, by using the ratios discussed in this paper, we obtain B ( B 0 → D + π − ) = (8.3 ± 1.0 ± 0.8) × 10 −7 .