Related papers: $\pi \Delta\Delta$ coupling constant
We exploit the quantum coherence between pair-produced D0 and D0bar in psi(3770) decays to study charm mixing, which is characterized by the parameters x and y, and to make a first determination of the relative strong phase \delta between…
We revisit the analysis of the improved ladder Schwinger-Dyson (SD) equation for the dynamical chiral symmetry breaking in QCD with emphasizing the importance of the scale ambiguity. Previous calculation done so far naively used one-loop…
Coupling constants of the pseudoscalar mesons to the octet baryons are calculated in the QCD sum rule approach. Two-point correlation function of the baryons are evaluated in a single meson state and the vacuum, which yields the designated…
The form factors and the coupling constant of the $B_s B^* K $ and $B_s B K^*$ vertices are calculated using the QCD sum rules method. Three point correlation functions are computed considering both the heavy and light mesons off-shell in…
Comparing perturbative calculations with a lattice computation of the static energy in quantum chromodynamics at short distances, we obtain a determination of the strong coupling alpha_s. Our determination is performed at a scale of around…
In the QCD sum rule approach we predict the $\Lambda$ (1405) mass by choosing the $\pi^0\Sigma^0$ multiquark interpolating field. It is found that the mass is about 1.419 GeV from $\Pi_1 (q^2)$ sum rule which is more reliable than $\Pi_q…
In this article, we calculate the strong coupling constants $g_{B_{s0} B_s \eta}$ and $g_{B_{s1} B^*_s \eta}$ with the light-cone QCD sum rules. Then we take into account the small $\eta-\pi^0$ transition matrix according to Dashen's…
We consider the hypothesis of a priori mixings in the mass eigenstates of mesons to obtain the |Delta I|=1/2 rule in K\to\pi\pi. The Hamiltonian responsible for the transition is the strong interacting one. The experimental data are…
From a fit to the experimental data on the $b\bar{b}$ fine structure, the two-loop coupling constant is extracted. For the 1P state the fitted value is $\alpha_s(\mu_1) = 0.33 \pm 0.01(exp)\pm 0.02 (th)$ at the scale $\mu_1 = 1.8 \pm 0.1$…
We give a brief review of our recent QCD analysis carried out over the deep inelastic scattering data on F2 structure function and in the non-singlet approximation to the accuracy up to next-to-next-to-leading-order. Specifically, analysis…
The widths of the strong decays $Z_c^{+}(3900)\to J/\psi \pi^{+}$ and $Z_c^{+}(3900)\to \eta_{c} \rho^{+}$ are calculated. To this end, the mass and decay constant of the exotic $Z_c^{+}(3900)$ state are computed by means of a two-point sum…
QCD sum rules on the light-cone are derived for the sum $f^+ + f^-$ of the $B\to \pi$ and $D\to \pi$ form factors taking into account contributions up to twist four. Combining the results with the corresponding $f^+$ form factors calculated…
The differential cross section for the $^{12}$C$(\gamma,\pi^{+}p)$ reaction has been measured in the $\Delta$(1232) resonance region at high recoil momenta of the residual nuclear system. The data are analyzed under the assumption that the…
We present an extension of the QCD sum rule method in the external fields so as to determine the induced pseudoscalar coupling constant g_P, which tests the validity of the partially conserved axial current (PCAC) hypothesis. This is…
We obtain a determination of the strong coupling alpha_s in quantum chromodynamics, by comparing perturbative calculations for the short-distance part of the static energy with lattice computations. Our result reads…
We present the results of the first lattice QCD study of the strong coupling g_{D^* D pi}. From our simulations in the quenched approximation, we obtain g_{D^* D pi} = 18.8 +/- 2.3^{+1.1}_{-2.0} and hat(g)_c = 0.67 +/- 0.08^{+0.04}_{-0.06}.…
We use a twice-subtracted partial-wave dispersion relation in the elastic unitarity approximation for final-state interactions to study the amplitude for the delta I = 1/2 CP-conserving weak process K+spurion->pi+pi. We use a simple…
The strong coupling constant alpha_s(mu_0), taken at a fixed reference scale mu_0, is the single free parameter of QCD and should be known to the highest available precision. The value of alpha_s should also be determined with good accuracy…
A high precision determination of the strong coupling constant in the MS-bar scheme at the Z-mass scale, using low energy quantities, namely pion/kaon decay constants and masses, as experimental input is presented. The computation employs…
A Roy equation analysis of the available $\pi\pi$ phase shift data is performed with the $I=0$ S- wave scattering length $a^0_0$ in the range predicted by the one-loop standard chiral perturbation theory. A suitable dispersive framework is…