K^{*} vector and tensor couplings from N_ {f}= 2 twisted mass QCD

Physical review D: Particles and fields (Impact Factor: 4.86). 07/2011; 84(1). DOI: 10.1103/PhysRevD.84.014505
Source: arXiv


The mass mK* and vector coupling fK* of the K* meson, as well as the ratio of the tensor to vector couplings fT/fV|K*, are computed in lattice QCD. Our simulations are performed in a partially quenched setup, with two dynamical (sea) Wilson quark flavors, having a maximally twisted mass term. Valence quarks are either of the standard or the Osterwalder-Seiler maximally twisted variety. Results obtained at three values of the lattice spacing are extrapolated to the continuum, giving mK*=981(33) MeV, fK*=240(18) MeV, and fT(2 GeV)/fV|K*=0.704(41).

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    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.
    Preview · Article · Jan 2012 · Journal of High Energy Physics

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