Related papers: One or two poles for the $\Xi(1820)$?

The existence of an anti-decuplet of pentaquark particles has been predicted some year ago within the chiral soliton model. In the last year, several experimental groups have reported evidence for a S=+1 baryon resonance, with mass ranging…

We have studied the meson-baryon interaction in the neutral $S=-2$ sector using an extended Unitarized Chiral Perturbation Theory, which takes into account not only the leading Weinberg-Tomozawa term (as all the previous studies in $S=-2$…

Within the chiral unitary approach, the axial-vector resonance $K_1(1270)$ has been predicted to manifest a two-pole nature. The lowest pole has a mass of 1195 Mev and a width of 246 Mev and couples mostly to $K^*\pi$, and the highest pole…

First measurements of the decays of the three $\chi_{cJ}$ states to $p\bar{p}K^{+}K^{-}$ final states are presented. Intermediate $\phi\to K^{+}K^{-}$ and $\Lambda(1520)\to pK^{-}$ resonance states are observed, and branching fractions for…

Inspired by the newly observed $\Xi_c^0$ states by the LHCb Collaboration, we investigate the OZI-allowed two-body strong decays of the $\lambda$-mode $1P$ wave $\Xi'_c$ states within the chiral quark model. Our results indicate that: (i)…

The axial vector meson $K_1(1270)$ was studied within the chiral unitary approach, where it was shown that it has a two-pole structure. We reanalyze the high-statistics WA3 experiment $K^- p\to K^-\pi^+\pi^- p$ at 63 GeV, which established…

The decay channel J/\psi --> \gamma \pi^+ \pi^- \eta^{\prime} is analyzed using a sample of 5.8\times 10^7 J\psi events collected with the BESII detector. A resonance, the X(1835), is observed in the \pi^+ \pi^- \eta^{\prime} invariant mass…

We present a theoretical study of $\Xi^*(1690)$ resonance in the $\Lambda_c^+ \to \Lambda K^+ \bar{K}^0$ decay, where the weak interaction part proceeds through the Cabibbo-favored process $c \to s + u\bar{d}$. Next, the intermediate two…

Recently, the Weinberg compositeness condition of a bound state was generalized to account for resonant states and higher partial waves. We apply this extension to the case of the $\Lambda(1520)$ resonance and quantify the weight of the…

Stimulated by the BESIII observation of $X(2100)$, $X(2500)$, and $\eta(2225)$, we try to pin down new pseudoscalar meson nonets including these states. The analysis of mass spectra and the study of strong decays indicate that $X(2120)$ and…

A multichannel calculation of excited $J^{PC}=1^{--}$ $\phi$ states is carried out within a generalization of the Resonance-Spectrum Expansion, which may shed light on the classification of the $\phi(2170)$ resonance, discovered by BABAR…

In this work, the molecular states from the \bar{K}^{*}\Sigma interaction are studied in a quasipotential Bethe-Salpeter equation approach with the one-boson-exchange potentials. We consider the exchanges of vector (\rho,\omega and \phi)…

The Lambda(1405) resonance is studied by a chiral unitary approach, in which the resonance is dynamically generated in coupled-channel meson-baryon scattering. Investigating the analytic structure of the scattering amplitudes obtained by…

The structure, spectroscopic parameters and width of the resonance with quantum numbers $J^{PC}=1^{++}$ discovered by the COMPASS Collaboration and classified as the $a_1(1420)$ meson are examined in the context of QCD sum rule method. In…

In this talk I summarize recent findings around the description of axial vector mesons as dynamically generated states from the interaction of pseudoscalar mesons and vector mesons, dedicating some attention to the two $K_1(1270)$ states.…

Recently, the BESIII Collaboration reported three resonances: $X(2232)$ with $M = 2232 \pm 19 \pm 27$ MeV and $\Gamma = 93 \pm 53 \pm 20$ MeV, $X(2200)$ whose mass $M = 2200 \pm 11 \pm 17$ MeV and width $\Gamma = 74 \pm 20 \pm 24$ MeV as…

Using data recorded by the CLEO II detector at CESR, we report evidence for two new charmed baryons, one decaying into $\Xi_c^+\pi^+\pi^-$ via an intermediate $\Xi_c^{*0}$, and its isospin partner decaying into $\Xi_c^0\pi^+\pi^-$ via an…

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…

In general, discrete eigenstates such as resonances are represented by poles of the scattering amplitude, analytically continued to the complex energy plane. In multi-channel scattering, however, the Riemann surface becomes more…

Cross sections, beam asymmetries, and recoil polarisations for the reactions gamma p to K^+ Lambda ; gamma to K^+ Sigma^0, and gamma p to K^0 Sigma^+ have been measured by the SAPHIR, CLAS, and LEPS collaborations with high statistics and…