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

TL;DR

This paper calculates D-meson decay constants using lattice QCD, examines heavy quark symmetry breaking, and tests factorization in B-meson decays, providing new insights into meson decay dynamics and correcting existing branching ratio values.

Contribution

It presents the first lattice QCD computation of vector meson decay constants and tests factorization in non-leptonic B-decays, highlighting significant heavy quark spin symmetry breaking effects.

Findings

fD* = 278 ± 13 ± 10 MeV

fDs* = 311 ± 9 MeV

fDs*/fD* = 1.16 ± 0.02 ± 0.06

Abstract

We compute the vector meson decay constants fD*, fDs* from the simulation of twisted mass QCD on the lattice with Nf = 2 dynamical quarks. When combining their 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, fDs*/fDs = 1.26(3), and (ii) to check the factorization approximation in a few specific B-meson non-leptonic decay modes. Besides our main results, fD* = 278 \pm 13 \pm 10 MeV, and fDs* = 311 \pm 9 MeV, other phenomenologically interesting results of this paper are: fDs*/fD* = 1.16 \pm 0.02 \pm 0.06, fDs*/fD = 1.46 \pm 0.05 \pm 0.06, and fDs/fD* = 0.89 \pm 0.02 \pm 0.03. Finally, we correct the value for B(B0 \rightarrow D+ pi-) quoted by PDG, and find B(B0 \rightarrow D+ pi-) = (7.8 \pm 1.4) \times 10-7. Alternatively, by using the ratios discussed in this paper, we obtain B(B0 \rightarrow D+ pi-) = (8.3 \pm 1.0 \pm 0.8)\times10-7.