Related papers: f_K/f_pi ratio from QCD sum rules
We compute the ratio of pseudoscalar decay constants f_K/f_pi using domain-wall valence quarks and rooted improved Kogut-Susskind sea quarks. By employing continuum chiral perturbation theory, we extract the Gasser-Leutwyler low-energy…
We compare the predictions for the form factors f_+^{D->pi,K}(0) from QCD sum rules on the light-cone with recent experimental results. We find f_+^{D->pi}(0) = 0.63\pm 0.11, f_+^{D->K}(0) = 0.75\pm 0.12 and f_+^{D->pi}(0)/f_+^{D->K}(0)=…
The coupling constant of g_phi-pi-gamma decay is calculated in the method of QCD sum rules. A comparison of our prediction on the coupling constant with the result obtained from analysis of the experimental data is performed.
A global fit to the shape of the first QCD Laplace sum rule exhibiting sensitivity to pion-resonance [$\Pi (1300)$] parameters is performed, leading to predictions for the pion-resonance mass and decay constant. This fit leads to…
We revisit QCD sum rules for the decay constants of heavy-light mesons. In the sum rules for the vector mesons B^*_(s) and D^*_(s) we improve the accuracy of OPE, taking into account the O(alpha_s^2) terms in the perturbative part and…
The coupling constant of (phi -> K K) decay is calculated in light cone QCD sum rules. The result obtained for g_{phi KK} = (4.9 pm 0.8) is in a good agreement with the existing experimental result.
We calculate the light pseudoscalar decay constants, f_pi and f_K, and their ratio using domain wall valence quarks and 2+1 flavors of dynamical staggered quarks. Use of the MILC gauge configurations allows us to simulate at several sea…
The strong coupling constant g_(Ko* K pi) of the scalar Ko* meson decay to (K pi) is calculated in light cone QCD sum rule. The predicted value of the coupling constant g_(Ko* K pi) is in a good agreement with the experimental result.
Coupling constants of the pseudoscalar mesons to the octet baryons are computed in the QCD sum rule approach. The pi-NN, eta-NN, pi-XiXi, eta-XiXi, pi-SigmaSigma, eta-SigmaSigma as well as pi-Lambda-Sigma couplings are studied. Determining…
In this article, we calculate the vector form factors $f^+_{K\pi}(Q^2)$ and $f^-_{K\pi}(Q^2)$ within the framework of the light-cone QCD sum rules approach. The numerical values of the $f^+_{K\pi}(Q^2)$ are compatible with the existing…
We reexamine radiative corrections to $\pi_{l2}$ and $K_{l2}$ decays. We perform a matching calculation, including vector and axial vector resonances as explicit degrees of freedom in the long distance part. By considering the dependence on…
We present our analysis of the decay constants of the beauty vector mesons $B^*$ and $B^*_s$ within the framework of dispersive sum rules for the two-point correlator of vector currents in QCD. While the decay constants of the vector mesons…
We determine the ratio FK/Fpi in QCD with Nf=2+1 flavors of sea quarks, based on a series of lattice calculations with three different lattice spacings, large volumes and a simulated pion mass reaching down to about 190 MeV. We obtain…
We show that a linear scaling between the weak decay constants of pseudoscalar and the vector mesons masses is supported by the available experimental data. The decay constant scale as $f_m/f_{pi}=M_V/M_{\rho}$ (f_m is decay constant and…
We report on our reexamination of the radiative corrections to $\pi_{l2}$ and $K_{l2}$ decays. We perform a matching calculation, using a specific model with vector meson dominance in the long distance part and the parton model in the short…
In this article, we study the vector and axialvector $B_c$ mesons with the QCD sum rules, and make reasonable predictions for the masses and decay constants, then calculate the leptonic decay widths. The present predictions for the masses…
The leptonic decay-constant ratio $f_K/f_\pi$ is calculated from lattice-QCD simulations using $N_f=2+1$ dynamical fermion flavors in the clover-improved formulation and 2-HEX smearing. The simulations were performed for a range of…
Global fits to the shape of the first QCD Laplace sum rule exhibiting sensitivity to pion-resonance [$\Pi (1300)$] parameters are performed, leading to predictions for the pion-resonance mass and decay constant. Two scenarios are considered…
The coupling constant of g_phi-pion-gamma decay is calculated using light cone QCD sum rules. A comparison of our result with the ones existing in the literature is presented.
A calculation of the ratio of leptonic decay constants f_{K^+}/f_{\pi^+} makes possible a precise determination of the ratio of CKM matrix elements |V_{us}|/|V_{ud}| in the Standard Model, and places a stringent constraint on the scale of…