Related papers: The Pion-Nucleon Coupling Constant in QCD Sum Rule…
The theoretical evaluation of the coupling constants gpiNN , gKNLambda and gKNSigma is undertaken using QCD sum rules. These quantities were previously calculated with exponential (Borel) kernels used to suppress the unknown contributions…
We employ QCD sum rules to calculate the coupling constants g$_{\rho\pi\gamma}$ and g$_{\omega\pi\gamma}$ by studying the three point ${\rho\pi\gamma}$- and ${\omega\pi\gamma}$-correlation functions. Our results for the decay widths…
We evaluate the pion-nucleon and the pion-Delta sigma terms by employing the method of quantum chromodynamics (QCD) sum rules. The obtained value of the pion-nucleon sigma term is compatible with the larger values already anticipated by the…
The pion nucleon vertex function at finite temperature is studied in the framework of: (a) the thermal (linear) sigma model to leading (one-loop) order, and (b) a thermal QCD-Finite Energy Sum Rule. Results from both methods indicate that…
The isovector GMO sum rule for zero energy forward pion-nucleon scattering is critically studied to obtain the charged pion-nucleon coupling constant using the precise negatively charged pion-proton and pion-deuteron scattering lengths…
In this article, the three point QCD sum rules is used to compute the strong coupling constants of vertices containing the strange bottomed ( charmed ) mesons with pion. The coupling constants are calculated, when both the bottom ( charm )…
The nucleon axial coupling constant $g_A$ is calculated in the presence of an external uniform magnetic field using finite energy sum rules. The correlation function of proton, neutron and axial-vector currents is calculated both the…
Two new sets of QCD sum rules for the nucleon axial coupling constants are derived using the external-field technique and generalized interpolating fields. An in-depth study of the predicative ability of these sum rules is carried out using…
We have calculated coupling constants of a neutral pion with the lowest two nucleon resonances. This includes both the diagonal as well as non-diagonal coupling constants involving a nucleon resonance and a nucleon. For this, we first…
The QCD sum rule calculation of the in-medium pion decay constants using pseudoscalar-axial vector correlation function, $i \int d^4x e^{ip\cdot x} < \rho| T[{\bar d}(x) i \gamma_5 u (x) {\bar u}(0) \gamma_\mu \gamma_5 d (0)] | \rho>$ is…
New QCD sum rules for the nucleon axial-vector current coupling constants are derived. One set is derived from a generalized correlator of spin-1/2 interpolating fields, and the other with a mixed correlator of spin-1/2 and spin-3/2 fields.…
The \pi NN^* and \eta NN^* coupling constants are studied based on the two point functions between the vacuum and a one meson state in the soft meson limit. In terms of a suitably constructed interpolating field for the nucleon and…
This work provides a brief history of determinations of the pion-nucleon ($\pi N$) coupling constant from $\pi N$ and $N N$ data. From robust analyses of twenty reported values of the charged-pion coupling constant, exhibiting sizeable…
Properties of the pion are studied at finite temperature with the help of the PCAC and the QCD sum rule. The pionic mode is treated consistently with the thermal pions which consist of the ground state at finite temperature. The temperature…
The QCD sum rules for spin-dependent nucleon-nucleon interactions are formulated and their physical implications are studied. The basic object of the study is the correlation function of the nucleon interpolating field, where the matrix…
In response to Kim's comment (nucl-th/9903040) on the sum rules for pion-baryon coupling constants obtained in hep-ph/9512259 and hep-ph/9606471, we point out that our treatment of the continuum is consistent with duality and with the fact…
Contents: 1. The sum rules or $\Gamma_{p,n}$.Theoretical status. 2. Calculations of matrix elements over the polarized nucleon by the QCD sum rule approach. 3. Twist-4 corrections to $\Gamma_{p,n}$ from QCD sum rules. 4. Gerasimov,…
For the heavy baryons $\Xi_c$ and $\Xi_b$ the coupling constants $g_{\Xi_c\Xi_c\pi}$ and $g_{\Xi_b\Xi_b\pi}$ are calculated in the framework of light cone QCD sum rules. The most general form of the interpolating field of $\Xi_Q$ is used in…
We start by studying the Goldberger-Treiman discrepancy (GTd) $\Delta = (2.259\pm 0.591)%$. Then we look at the $\pi N$ $\sigma$ term, with the dimensionless ratio $\sigma_N/2m_N=3.35%$. Finally we return to predicting (via the quark model)…
We derive QCD sum rules from the nucleon two-point function in nuclear medium, calculating its specral function in chiral perturbation theory to one loop. Our calculation shows the inadequacy of the commonly used ansatz to represent the…