相关论文: Evidence for Some New Hyperon Resonances -- to be …
Distinctive patterns are predicted by quenched quark models and unquenched quark models for the lowest SU(3) baryon nonet with spin parity $J^P=1/2^-$. While the quenched quark models predict the lowest $1/2^-$ $\Sigma^*$ resonance to be…
The unquenched quark models predict the new particle $\Sigma^*$ with spin parity $J^P=1/2^-$ and its mass is around the well established $\Sigma^*(1385)$ with $J^P=3/2^+$. Here by using the effective Lagrangian approach we study \kp\…
The low mass of the $\Lambda(1405)$ hyperon with $j^P = 1/2^-$, which is higher than the ground state $\Lambda(1116)$ mass by 290 MeV, is difficult to understand in quark models. We analyze the hyperon spectrum in the bound state approach…
The classical quenched quark models with three constituent quarks provide a good description for the baryon spatial ground states, but fail to reproduce the spectrum of baryon excited states. More and more evidences suggest that unquenched…
We study hyperon resonances by solving coupled channel scattering equations. The coupled systems include pseudoscalar- and vector-baryon channels. The parameters of the model are restricted by making a $\chi^2$-fit to the cross section data…
The coupling to light mesons leads to large widths and shifts of the energy of the excited states in the baryon spectrum from the predictions of the constituent quark model with three valence quarks. This coupling may be modelled by…
The LHCb Collaboration has recently observed two narrow baryon resonances with beauty. Their masses and decay modes look consistent with the quark model orbitally excited states Lambda_b(5912) and Lambda*_b(5920), with quantum numbers…
Quark models taking into account the dynamical effects of hadronic decay often produce very different predictions for mass shifts in the hadron spectrum. The consequences for meson spectroscopy can be dramatic and completely obscure the…
In recent years, the discovery in quarkonium spectrum of several states not predicted by the naive quark model has awakened a lot of interest. A possible description of such states requires the enlargement of the quark model by introducing…
Many candidate multiquark mesons, i.e., mesons with substructures that are more complex than the quark-antiquark prescription that is in the textbooks, have recently been observed. Many of the most recently observed candidate states are…
About 120 baryons and baryon resonances are known, from the abundant nucleon with $u$ and $d$ light-quark constituents up to the recently discovered $\Omega_b^-=bss$, and the $\Xi_b^-=bsd$ which contains one quark of each generation. In…
In this talk I show recent results on how many excited baryon resonances appear as systems of one meson and one baryon, or two mesons and one baryon, with the mesons being either pseudoscalar or vectors. Connection with experiment is made…
We report properties of $\Lambda$ and $\Sigma$ hyperon resonances formed in $K^-$ induced reactions. Special emphasis is laid on the analysis of the three-body final states $2\pi^0\Lambda$ and $2\pi^0\Sigma$ and of the quasi-two-body final…
Early data on $K^-$ induced reactions off protons are collected and used in a coupled-channel partial wave analysis (PWA). Data which had been published in the form of Legendre coefficients are included in the PWA. In a {\it primary} fit…
Two structures are observed close to the kinematic threshold in the $\Xi_b^0 \pi^-$ mass spectrum in a sample of proton-proton collision data, corresponding to an integrated luminosity of 3.0 fb$^{-1}$ recorded by the LHCb experiment. In…
We extract, from a quark model potential that reproduces the number and ordering of nonstrange baryonic resonances up to 2.3 GeV, the quantum numbers for the dominant configurations in the ground and first non-radial excited states. From…
A simple argument for the restoration of parity symmetry high in the hadron spectrum is presented. The restoration scale is estimated to be 2.5 GeV. This in turn implies that typical quark model phenomenology such as scalar confinement or…
Recent experiments of photon-nucleon and meson-nucleon scatterings have accumulated a lot of data for various meson production processes. One of the purposes of those experiments is to search for the missing resonances which are not…
he observed well-known resonances $\Sigma^0$ $\Sigma^{*+}$(1385) and $K^{*\pm}$(892) from PDG are good tests of this method. Exotic strange multibaryon states have been observed in the effective mass spectra of: $\Lambda \pi^{\pm}$,$\Lambda…
Indications for the production of a neutral excited hyperon in the reaction pp -> p K^+ Y^{0*} are observed in an experiment performed with the ANKE spectrometer at COSY-J\"ulich at a beam momentum of 3.65 GeV/c. Two final states were…