Related papers: Pion couplings with low-lying nucleon resonances
We compare phenomenological values of the frozen QCD running coupling constant ($\alpha_s$) with two classes of solutions obtained through nonperturbative Schwinger-Dyson equations. We use these same solutions with frozen coupling constants…
We present a study of neutrino/antineutrino induced charged and neutral current single pion production off the nucleon. For this, we have considered $P_{33}(1232)$ resonance, non-resonant background terms, other higher resonances like…
We present an analysis of QCD sum rules for pion form factor in next-to-leading order of perturbation theory for the case of pseudoscalar pion currents. The essential instanton contribution is reanalysed with account for present more…
Scalar form factor of the nucleon is calculated in the framework of light cone QCD sum rules, using the most general form of the baryon current. Using the result on scalar form factor of the nucleon, the nucleon-scalar "sigma" and "a_0"…
We demonstrate that the polaron theory from solid state physics can serve as an interesting analogue model for non-perturbative QCD, at least in the description of nucleons and related low-energy physics of strong interactions. By drawing…
We show on two examples, namely a calculation for charge symmetry breaking in pn->d pi^0 that allows one to extract the quark mass difference induced part of the proton--neutron mass difference and a high precision calculation for…
Results of a relativistic model for pion- and photon-induced reactions on the proton are presented. The model is crossing symmetric and gauge invariant. The nucleon resonances P_11 (1440), P_11 (1710), D_13 (1520), S_11 (1535), S_11 (1650),…
The short-time regime of QCD two-point correlation functions is examined through a QCD-Sum-Rule-inspired continuum model. QCD Sum Rule techniques are tested and alternate nucleon interpolating fields are discussed. The techniques presented…
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…
We study baryon and diquark correlation functions in the framework of an instanton model for the QCD vacuum. The model naturally accomodates a light scalar diquark. As a consequence, the correlation functions for the nucleon and delta are…
The magnetic polarisability is a fundamental property of hadrons, which provides insight into their structure in the low-energy regime. The pion magnetic polarisability is calculated using lattice QCD in the presence of background magnetic…
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…
Lattice simulations of QCD have produced precise estimates for the masses of the lowest-lying hadrons which show excellent agreement with experiment. By contrast, lattice results for the vector and axial vector form factors of the nucleon…
The simple model describing charge independence and charge symmetry breaking of the pion-nucleon coupling constant is proposed. The model, which has simple physical meaning and foundation, suggests directly proportional dependence of the…
We compute the Form Factors of both neutral and charged pion using a non-perturbative running of the strong coupling constant $\alpha_s$ obtained using a double-dilaton Holographic QCD model. These form factors remain poorly understood in…
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…
We calculate the strong couplings of pions to the Delta(1232) resonance using a QCD parameterization method that includes in addition to the usual one-quark also two-quark and previously uncalculated three-quark operators. We find that…
In the Yukawa model for nuclear forces, a simple relation between the charged and neutral pion-nucleon coupling constants is derived. The relation implies that the charged pion-nucleon coupling constant is larger than the neutral one since…
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 effective interaction between a quark and an anti-quark as obtained previously with by the method of iterated resolvents is replaced by the so called up-down-model and applied to flavor off-diagonal mesons including the pion. The only…