Related papers: Working group summary: pi-N sigma term
In this talk I discuss some recent developments in physics beyond the Standard Model. After some initial comments on neutrino masses, I discuss the status of low-energy supersymmetry and finally turn to describing some recent work in…
We generalize the linear sigma model in order to develop a chiral-invariant model of nuclear structure. The model is natural, and contains not only the usual sigma meson which is the chiral partner of the pion but also a new chiral-singlet…
After showing the characteristic features of the chiral transition in QCD at finite temperature $T$, we note the significance of the sigma-mesonic mode in the chiral transition : Sigma meson may be regarded as the "Higgs particle" in QCD,…
We analyze elastic-pion nucleon scattering to third order in the so-called small scale expansion. It is based on an effective Lagrangian including pions, nucleons and deltas as active degrees of freedom and counting external momenta, the…
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.…
Using recent experimental evidence from E791 on the sigma meson in D \to 3\pi decays, we study the relevant couplings in D \to \sigma \pi and \sigma \to \pi\ pi within the accepted theoretical framework for non leptonic D decays. We also…
It is shown that the binding effect that is associated with the short range part of the Goldstone boson exchange interaction between constituent quarks provides a good description of the $\pi N$ $\sigma$-term.
There are several different experimental indications, such as the pion-nucleon sigma term and polarized deep-inelastic scattering, which suggest that the nucleon wave function contains a hidden s bar s component. This is expected in chiral…
As the residual interaction of quantum chromodynamics in low-energy region, the nucleon-nucleon (NN) potential can only be exactly described by the model picture now. In the Bonn potential, one of the most well-known NN interaction models,…
In a previous paper, we reported the results of a partial-wave analysis of the pion-nucleon ($\pi N$) differential cross sections (DCSs) of the CHAOS Collaboration and came to the conclusion that the angular distribution of their $\pi^+ p$…
The purpose of this note is to report predictions of the binding energy of the $\Lambda$ hyperon in nuclear matter using the latest version of the Juelich nucleon-nucleon meson-exchange potential. Results from a conventional Brueckner…
In the phenomenological description of the nuclear interaction a crucial role is traditionally played by the exchange of a scalar I=0 meson, the sigma, of mass 500-600 MeV, which however is not seen clearly in the particle spectrum and…
This paper summarizes our studies of the hypertriton and describes our findings on the hyperon-nucleon interaction, especially on the role of the $\Lambda N-\Sigma N$ coupling and the strengths of the $S$-wave $YN$ interactions. We briefly…
The $\omega$-meson photoproduction, $\gamma+p\to p+\omega$, is studied in the framework of a model, containing $\pi$-meson exchange in t-channel and nucleon-exchange in s- and u-channels. Considering both $\omega NN$-coupling constants in…
The J\"ulich-Bonn group aims at an extensive study of the baryon-baryon ($BB$) interaction involving strange baryons ($\Lambda$, $\Sigma$, $\Xi$) within SU(3) chiral effective field theory. An overview of achievements and new developments…
Next to leading order effective field theory calculations are performed for $ {}^1S_0$ NN scattering using subtractive renormalization procedure. One pion exchange and contact interaction potentials are iterated using Lippman-Schwinger…
A model is developed for the hadronic and electromagnetic interaction in the two-nucleon system above pion threshold in the framework of meson, nucleon and $\Delta$ degrees of freedom. It is based on time-ordered perturbation theory and…
A group theoretical description of the Majorana-Oppenheimer quantum electrodynamics is considered. Different spinor realizations of the Maxwell and Dirac fields are discussed. A representation of the Majorana-Oppenheimer wave equations in…
The past two decades have witnessed tremendous progress in the microscopic description of atomic nuclei. The Topical Review `The Future of Nuclear Structure' aims at summarizing the current state-of-the-art microscopic calculations in…
Recent experimental and theoretical advances in investigating electromagnetic meson production reactions in the nucleon resonance region are reviewed.