相关论文: Suppression of PiNN(1535) Coupling in the QCD Sum …
The \pi NN^* and \eta NN^* coupling constants are studied in the QCD sum rule ($N^* \equiv N(1535)). We investigate the two point functions between the vacuum and a one meson state in the soft meson limit. The operator product expansion is…
The light cone QCD sum rules are employed to calculate the $\pi N N(1535)$ coupling $g_{\pi N N^\ast}$. We study the two point correlation function of two nucleon currents sandwiched between the vacuum and the pion state. The contribution…
The light cone QCD sum rules are derived for the $\pi NN$ coupling $g_{\pi NN}$ and $\pi NN(1535)$ coupling $g_{\pi NN^\ast}$. The contribution from the excited states and continuum is subtracted cleanly through double Borel transformation.…
We calculate the coupling constants, $g_{\pi NS_{11}}$ and $g_{\eta NS_{11}}, using QCD sum rules in the presence of an external meson field. A covariant derivative is introduced within the S_{11} interpolating field so that in the…
Meson-baryon couplings between positive and negative parity nucleons are investigated using two point correlation functions in the soft meson and the chiral limit. We find that the pi NN* coupling vanishes due to chiral symmetry, while the…
We study the strong vertices $N^*N\pi$, $N^*N^*\pi$ and $NN\pi$ in QCD, where $N^*$ denotes the negative parity $N (1535)$ state. We use the most general form of the interpolating currents to calculate the corresponding strong coupling…
We employ the light cone QCD sum rules to calculate $\Delta\pi N$ coupling constant by studying the two point correlation function between the vacuum and the pion state. Our result is consistent with the traditional QCD sum rules…
Meson-baryon couplings between positive and negative parity baryons are investigated using two point correlation functions in the soft meson limit. We find that the pi NN^* coupling vanishes due to chiral symmetry, while the eta NN^*…
We study the $\eta$NN coupling constant using the method of QCD sum rules starting from the vacuum-to-eta correlation function of the interpolating fields of two nucleons. The matrix element of this correlation has been taken with respect…
We derive the light cone QCD sum rule for the $\eta NN$ coupling constant $g_{\eta NN} $. The contribution from the excited states and the continuum is subtracted cleanly through the double Borel transform with respect to the two external…
In this article, we firstly analyze the mass and pole residue of negative parity nucleon $N^*(1535)$ within the two-point QCD sum rules. Basing on these results, we continuously study the strong coupling constants of vertices…
We evaluate the $\pi N$ coupling constant using a QCD sum rule based on the pion-to-vacuum matrix element of the correlator of two interpolating nucleon fields. The part of the correlator with Dirac structure $k\llap/\gamma_5$ is used,…
Coupling constants of $\eta$ and $\eta^{\prime}$ mesons with nucleons have been calculated using the method of QCD sum rules. Starting from vacuum-to-meson correlation function of interpolating fields of two nucleons, its matrix element…
We estimate strong coupling constant between the negative parity nucleons with $\pi$ meson within the light cone QCD sum rules. A method for eliminating the unwanted contributions coming from the nucleon--nucleon and nucleon--negative…
We compute the strong coupling constant $g_{P^* P \pi}$, with $P$ and $P^*$ respectively pseudoscalar and vector heavy mesons by using the QCD sum rules approach. Our computation is based on the evaluation of the time ordered product of…
Jido, Oka and Hosaka have shown that the p-slash gamma_5 piece of the pion-to-vacuum correlator of two baryon interpolating fields vanishes in the soft-pion limit, as a consequence of chiral transformation properties of those fields. This…
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 pion-nucleon coupling constant $g_{\pi N}$ is studied on the basis of the QCD sum rules. Both the Borel sum rules and the finite energy sum rules for $g_{\pi N}$ are used to examine the effects of higher dimensional operators (up to…
We use QCD sum rules to obtain the weak parity-violating pion-nucleon coupling constant $f_{\pi NN}$. We find that $f_{\pi NN}\approx 2\times 10^{-8}$, about an order of magnitude smaller than the ``best estimates'' based on quark models.…
We use QCD sum rules to obtain the weak parity-violating pion-nucleon coupling constant $f_{\pi NN}$. We find that $f_{\pi NN}\approx 3\times 10^{-8}$, up to an order of magnitude smaller than the ``best estimates" based on quark models.…