Related papers: Chiral baryon in the coherent pair approximation
We present a nucleon-nucleon potential at fifth order in chiral effective field theory. We find a substantial improvement in the description of nucleon-nucleon phase shifts as compared to the fourth-order results of Ref. [E. Epelbaum, H.…
Recent developments for chiral and $U(1)_A$ restorations in excited hadrons are reviewed. We emphasize predictions of the chiral symmetry restoration scenario for axial charges and couplings to Goldstone bosons. Using very general chiral…
We investigate threshold pion photoproduction in the framework of heavy baryon chiral perturbation theory. We give the expansion of the electric dipole amplitude $E_{0+}$ to three orders in $\mu$, the ratio of the pion to nucleon mass, and…
We apply the perturbative chiral quark model (PCQM) at one loop to analyze the axial form factor of the nucleon. This chiral quark model is based on an effective Lagrangian, where baryons are described by relativistic valence quarks and a…
We present an accurate nucleon-nucleon (NN) potential based upon chiral effective Lagrangians. The model includes one- and two-pion exchange contributions up to chiral order three and contact terms (which represent the short range force) up…
A modified linear sigma model that allows for $g_A = 1.26$ by addition of vector and pseudovector $\pi N$ coupling terms was discussed by Bjorken and Nauenberg and by Lee. In this extended linear sigma model the elastic $\pi $N scattering…
The pion-nucleon coupling constants determine the strength of the long-range nuclear forces and play a fundamental part in our understanding of nuclear physics. While the charged- and neutral-pion couplings to protons and neutrons are…
We propose a new, renormalizable approach to nucleon-nucleon scattering in chiral effective field theory based on the manifestly Lorentz invariant form of the effective Lagrangian without employing the heavy-baryon expansion. For the…
We calculate chiral corrections to the semileptonic vector and axial quark coupling constants using a manifestly Lorentz covariant chiral quark approach up to order O(p4) in the two- and tree-flavor picture. These couplings are then used in…
We calculate the pion-nucleon scattering lengths $a_{0}^{(\pm)}$ and the mass parameter $m_{0}$, which describes the nucleon mass in the chiral limit, at tree-level in the framework of a globally symmetric linear sigma model with…
Chiral-parity (parity-doublet) effective Lagrangian models provide a compact and symmetry-consistent framework for describing baryons and their negative-parity partners in terms of linearly-realized chiral symmetry. Unlike the conventional,…
We compute pion-nucleon scattering at tree-level within a gauged linear sigma model which contains the nucleon and its chiral partner. Such an investigation in principle allows to make definite predictions as to whether the main…
We apply the perturbative chiral quark model (PCQM) to analyse low-energy nucleon properties: electromagnetic form factors, meson-nucleon sigma-terms and pion-nucleon scattering. Baryons are described as bound states of valence quarks…
Understanding hadron structure within the framework of QCD is an extremely challenging problem. In order to solve it, it is vital that our thinking should be guided by the best available insight. Our purpose here is to explain the model…
Within the pion-nucleon chiral perturbation theory we derive the leading chiral correction to the nucleon GPD at $\xi=0$. We discuss the difficulties of consideration of nonlocal light-cone operators within the theory with a heavy particle…
We analyze the octet baryon masses and the pion/kaon--nucleon $\sigma$--terms in the framework of heavy baryon chiral perturbation theory. We include {\it all} terms up-to-and-including quadratic order in the light quark masses, $m_q$. We…
We review the Rein--Sehgal model and criticize its use for low energy neutrino induced coherent pion production. We have studied the validity of the main approximations implicit in that model, trying to compare with physical observables…
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…
Motivated by the recent progress in developing high-precision relativistic chiral nucleon-nucleon interactions, we study the antinucleon-nucleon interaction in a hybrid approach where the real part of the potential is constructed in the…
Theoretical as well as experimental progress has been made in the last decade in describing the properties of baryons. In this review I will mostly report on the theoretical issues. Two non-perturbative methods are privileged frameworks for…