相关论文: About QCD sum rules for pion-nucleon coupling
QCD sum rules are useful tools for studying the spectral properties of hadrons; however, assumptions underlying standard sum-rule analyses can lead to inconsistencies with known results of chiral perturbation theory. This possibility is…
We compute the $J/\psi \pi\to {charmed mesons}$ cross section using QCD sum rules. This cross section is important to distinguish the suppression in the production of $J/\psi$ through the dissociation by comoving pions and through the…
We calculate the coefficients of the dimension-8 quark and gluon condensates in the current-current correlator of $1^{-+}$ light hybrid current $g\bar{q}(x)\gamma_{\nu}iG_{\mu\nu}(x)q{(x)}$. With inclusion of these higher-power corrections…
Using the PDG 22 compilation of the $e^+e^-\to$ Hadrons $\oplus$ the recent CMD3 data for the pion form factor and the value of gluon condensate $<\alpha_s G^2>$ from heavy quarkonia, we extract the value of the four-quark condensate :…
We undertake a covariance error analysis of the pion-nucleon-nucleon coupling constants from the Granada-2013 np and pp database comprising a total of 6720 scattering data below LAB energy of 350 MeV. Assuming a unique pion-nucleon coupling…
The $B^*B\pi$ and $D^*D\pi$ couplings have previously been derived from a QCD light-cone sum rule in leading order. Here, we describe the calculation of the $O(\alpha_s)$ correction to the twist 2 term of this sum rule. The result is used…
We analyze QCD and Weinberg-type sum rules in a low-temperature pion gas using vector and axial-vector spectral functions following from the model-independent chiral-mixing scheme. Toward this end we employ recently constructed vacuum…
In the context of QCD sum rules with non-local condensates we present a pion distribution amplitude, which is double-humped with its end-points x\to(0,1) strongly suppressed, and show that it matches the CLEO experimental data on the…
The coupling constant of f0-->omega-gamma decay is calculated using 3-point sum rule and light cone QCD sum rules. We investigate the results within the two-models which depend on mixing angle.
We study the generalized sum rules and polarizabilities of the nucleon in the framework of the hypercentral constituent quark model. We include in the calculation all the well known $3^*$ and $4^*$ resonances and consider all the…
Corrections due to gluon condensate to electromagnetic form factors of the transition $\pi+\gamma^* \to A_1$ are calculated by standard QCD sum rules technique. The obtained results are compared to the corresponding light-cone QCD sum…
We study the N pi N coupling, in the framework of a QCD-inspired confining Nambu-Jona-Lasinio model. A simple relativistic confining and instantaneous quark model is reviewed. The Salpeter equation for the nucleon and the boosted pion is…
We investigate the QCD phase diagram as a function of isospin chemical potential at a fixed temperature by directly putting large numbers of \pi^+s into the system. Correlation functions of N \pi^+s systems involves N!N! contractions, and…
We use light-cone QCD sum rules to evaluate the strong coupling $g_{f_0 K^+ K^-}$ which enters in several analyses concerning the scalar $f_0(980)$ meson. The result: $6.2\le g_{f_0 K^+ K^-}\le 7.8$ GeV is larger than in previous…
We compute the quark and gluon condensates in $QCD$ with $N$ colors and $N_f$ flavors based on the renormalization group equations and on the knowledge of a single scale $\Lambda_{QCD}$. For $N=3$ and $N_f=3$ our findings are in the good…
We extend previous work on sum rules for the invariant amplitudes of pion Compton scattering by deriving a complete lowest order perturbative spectral function - and its leading non perturbative power corr ections - for a specific…
I use QCD sum rule ideas to construct models for generalized parton distributions. To this end, the perturbative parts of QCD sum rules for the pion and nucleon electromagnetic form factors are interpreted in terms of GPDs and two models…
We analyze the higher-twist effects and the SU(3)-flavour symmetry breaking in the correlation functions used to calculate form factors of pseudoscalar mesons in the QCD light-cone sum rule approach. It is shown that the Ward identities for…
We summarize results obtained in our studies of the pion-nucleon coupling constant. Several different techniques have been applied to pi-N and NN elastic scattering data, and the existing database for single-pion photoproduction. The most…
We extend previous calculations of leading-order correlation functions of spin-0 and spin-1 light quarkonium hybrids to include QCD condensates of dimensions five and six, with a view to improving the stability of QCD sum-rules analyses in…