Related papers: Evidence for two Lambda(1405) resonance states
The scattering length and effective range of the piSigma channel are studied in order to characterize the strangeness S=-1 meson-baryon scattering and the Lambda(1405) resonance. We examine various off-shell dependence of the amplitude in…
By using an effective Lagrangian method, we study the effects of a newly proposed $\Sigma^*(1/2^-)$ state with mass around 1380 MeV in the initial-state polarized $\gamma N\rightarrow K^{+} \Sigma^*(1385) \rightarrow K^{+} \pi \Lambda$…
The reaction K- d -> pi Sigma N is investigated taking into account single scattering and the two-step process due to Kbar N -> pi Sigma rescattering. The influence of some common approximations are examined. It is found that the treatment…
A recently developed non-perturbative chiral approach to dynamically generate the (3/2^-) baryon resonances has been extended to investigate the radiative decays Lambda^*(1520) --> gamma Lambda(1116) and Lambda^*(1520) --> gamma…
The $\Lambda(1405)$ production in p+p collisions at 3.5 GeV and K$^-$-induced reactions is discussed. The shift of the measured spectral function of the $\Lambda(1405)$ in p+p reactions does not match either theoretical calculations for p+p…
We perform a theoretical analysis of the $\Lambda_b \to J/\psi K^- p$ reaction from where a recent LHCb experiment extracts a $\Lambda(1405)$ contribution in the $K^- p$ spectrum close to threshold and two baryon states of hidden charm in…
The total and differential cross sections for associated strangeness production in the $pp \to pK^+K^-p$ and $pp \to pK^+\pi^0\Sigma^0$ reactions have been studied in a unified approach using an effective Lagrangian model. It is assumed…
In this talk a brief review of several problems involving systems with strangeness is made. In the first place one shows how the $\Lambda (1405)$, $\Lambda(1670)$ and $\Sigma(1620)$ states, for $S = -1$, and the $\Xi(1620)$ for $S= -2$ are…
The review on the 2m propane bubble chamber experiment data analysis aimed to searches for an exotic baryon states for $K^0_s$-meson subsystems. The observation of $\Sigma^0$, $\Sigma^{*+}$(1385) and $K^{*\pm}$(892) well known resonances…
We discuss in this talk aspects of \bar{K}N plus coupled channels dynamics with special emphasis on the \Lambda(1405) resonance and isovector resonances in the same energy region. We comment on several experimental reactions giving rise to…
Among the light baryons, the $J^\pi = \frac{1}{2}^-$ $\Lambda(1405)$ hyperon is an important special case as it sits just below the $N\bar{K}$ threshold and decays almost exclusively to $\Sigma\pi$. Some long-standing hypotheses for…
The $\Lambda(1520)$ resonance has been recently studied in a unitarized coupled channel formalism with $\pi\Sigma(1385)$, $K\Xi(1530)$, $\bar{K}N$ and $\pi\Sigma$ as constituents blocks. We provide a theoretical study of the predictions of…
We present a unified picture which studies simultaneously the gamma gamma--> pi^+ pi^-, pi^0 pi^0,K^+ K^-, K^0 bar{K}^0, pi^0 eta reactions up to about sqrt(s)=1.4 GeV reproducing the experimental cross sections. The present work implements…
The LEPS collaboration has recently reported a measurement of the reaction $\gamma n\to K^+\Sigma^{*-}(1385)$ with linearly polarized photon beam at resonance region. The observed beam asymmetry is sizably negative at $E_\gamma=1.8-2.4…
We study the $\Lambda(1520)D_{03}$ in a chiral coupled channel approach. This resonance appears as dynamically generated from the interaction of the decuplet of baryons and the octet of mesons in s-wave, and its treatment is improved here…
Since the discovery of the $\Lambda(1405)$, it remains poorly described by conventional constituent quark models, and it is a candidate for having an "exotic" meson-baryon or "penta-quark" structure, similar to states recently reported in…
The reaction $\gamma p\to p\pi^0\eta$ has been studied with the CBELSA detector at the tagged photon beam of the Bonn electron stretcher facility. The reaction shows contributions from $\Delta^+(1232)\eta$, $N(1535)^+\pi^0$ and $pa_0(980)$…
We report a theoretical study of the $pp\to p K^+\Lambda(1405)$ reaction, which was recently investigated at COSY-J\"{u}lich by using a 3.65 GeV/c circulating proton beam incident on an internal hydrogen target. The reaction is driven by…
Results from a partial-wave analysis of the reaction $\gamma p \rightarrow K^+ \Lambda$ are presented. The reaction is dominated by the $S_{11}(1650)$ and $P_{13}(1720)$ resonances at low energies and by $P_{13}(1900)$ at higher energies.…
The pion- and photon induced reactions for the final states $\gamma N$, $\pi N$, $2\pi N$, $\eta N$, and $\omega N$ are studied within a coupled-channel effective Lagrangian approach in the energy region from the pion threshold up to 2 GeV.…