相关论文: Exploring Baryon Chiral Multiplets
I discuss the problem of constructing an effective low-energy theory in the vicinity of a resonance or a bound state. The focus is on the example of the $\Delta(1232)$, the lightest resonance in the nucleon sector. Recent developments of…
We extend a previous analysis of the lowest-lying octet baryon masses in covariant baryon chiral perturbation theory (ChPT) by explicitly taking into account the contribution of the virtual decuplet baryons. Up to…
Although there are phenomenological indications that the low-energy constants in the chiral lagrangian may be understood in terms of a finite number of hadronic resonances, it remains unclear how this follows from QCD. One of the arguments…
In this two part series a chiral confining model of baryons is used to describe low--lying negative parity resonances $N^*$, $\Delta^*$, $\Lambda^*$ and $\Sigma^*$ in the mean field approximation. A physical baryon in this model consists of…
I review the results of hadron spectroscopy calculations from lattice QCD for an intended audience of low energy hadronic physicists. I briefly introduce the ideas of numerical lattice QCD. The various systematic errors, such as the lattice…
I review recent progress made in the calculation of nucleon properties in the framework of heavy baryon CHPT. Topics include: Compton scattering, $\pi N$ scattering, the anatomy of a low-energy constant and the induced pseudoscalar form…
Two ideas have greatly contributed to our understanding of baryon structure in the framework of Quantum Chromodynamics (QCD). The first, chiral symmetry, received its fundamental justification from QCD and has been developed into the…
The positive-parity nucleon spectrum is explored in $2 + 1$-flavour lattice QCD in a search for new low-lying energy eigenstates near the energy regime of the Roper resonance. In addition to conventional three-quark operators, we consider…
The ground state masses and binding energies of the nucleon, $\Lambda^0$, $\Lambda^+_c$, $\Lambda^0_b$ are studied within a constituent quark QCD-inspired light-front model. The light-front Faddeev equations for the $Qqq$ composite spin 1/2…
Algorithmic progress in recent years made it possible to simulate QCD with Nf=2 flavours of O(a)-improved Wilson fermions at very light quark masses. We present the current results for baryon spectrum states, the nucleon axial coupling and…
I consider some selected topics in chiral perturbation theory (CHPT). For the meson sector, emphasis is put on processes involving pions in the isospin zero S-wave which require multi-loop calculations. The advantages and shortcomings of…
Several conceptual points concerning the inclusion of the $\Delta$(1232) resonance in the framework of chiral effective-field theory are discussed, with an emphasis on the problem of power counting in the baryon sector in general. I also…
After contrasting the low energy effective theory for the baryon sector with one for the Goldstone sector, I use the example of pion nucleon scattering to discuss some of the progress and open issues in baryon chiral perturbation theory.
In this talk, I discuss methods that allow for a systematic and model-independent calculation of the hadron spectrum. These are lattice QCD and/or its corresponding Effective Field Theories. Assorted results are shown and I take the…
With an effective chiral flavour SU(3) model we show the effect of hadronic resonances on the QCD phase diagram. We state that varying the resonance couplings to the scalar and vector fields affects the order and location of the phase…
It is argued that an appearance of the near parity doublets in the upper part of the light baryon spectrum is an evidence for the chiral symmetry restoration in the regime where a typical momentum of quarks is around the chiral symmetry…
Mass differences of the flavor octet and decuplet ground-state baryons are studied in the perturbative chiral quark model. We present a way to understand the nontrivial spin- and flavor dependent mass differences, where both pseudoscalar…
The regularities in the spectrum of the light baryon resonances are reviewed and compared with those of the light mesons. We discuss the occurrence of parity doublets and clusters, and note the trends in the values of the masses, widths,…
In the first part of the talk, I discussed results on the determination of the ratios of the light quark masses from large N_c chiral perturbation theory, to be described elsewhere. The following notes contain material from the second part…
Hadron structure and nuclear structure are discussed from the common ground of effective chiral Lagrangians modeling QCD at low energy. The topics treated are the chiral bag model in large $N_c$ QCD, its connection to heavy-baryon chiral…