Related papers: Two pole structure of the Lambda(1405) resonance
We show that the recently measured asymmetry in helicity-angle spectra of the Lambda-hyperons produced in the reaction pp -> K^+Lambda p reaction and the energy dependence of the total pp -> K^+Lambda p cross section can be explained…
We analyze $\pi\pi-K\bar{K}$ and $\pi\eta-K\bar{K}$ couple channel [1,1] matrix Pad\'e amplitudes of $SU(3)\times SU(3)$ chiral perturbation theory. By fitting phase shift and inelasticity data, we determine pole positions in different…
In this work, we perform a \textit{toy-model} analysis for the unpolarized photo- and electroproduction of $\Lambda(1405)\equiv\Lambda^*$ via $\gamma^{(*)}p\to K^+\pi^+\Sigma^-$ by employing the effective Lagrangian approach at the tree…
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…
Within an extended chiral constituent quark model, three- and five-quark structure of the $S_{01}$ resonance $\Lambda(1405)$ is investigated. Helicity amplitudes for the electromagnetic decays ($\Lambda(1405) \to \Lambda(1116)\gamma$,…
The two-pole structure refers to the fact that particular single states in the spectrum as listed in the PDG tables are often two states. The story began with the $\Lambda(1405)$, when in 2001, using unitarized chiral perturbation theory,…
Role of the $\Lambda(1600)$ is studied in the $K^- p \to \Lambda \pi^0 \pi^0$ reaction by using the effective Lagrangian approach near the threshold. We perform a calculation for the total and differential cross sections by considering the…
We investigate the $K^- p \to \gamma \Sigma$ reaction using an effective Lagrangian approach within an isobar model framework. The model includes contributions from $s$-channel hyperon and hyperon resonance, $t$-channel $K$ and $K^*$,…
The first observation of two structures consistent with resonances in the final states $\Lambda_b^0 \pi^-$ and $\Lambda_b^0 \pi^+$ is reported using samples of $pp$ collision data collected by the LHCb experiment at $\sqrt{s} = 7$ and $8$…
We study the $\Lambda(1520)$ resonance in a coupled channel approach involving the $\pi\Sigma(1385)$, $K\Xi(1530)$, $\bar{K}N$ and $\pi\Sigma$ channels. Implementing unitarity in coupled channels, we make an analysis of the relative…
We propose a new QCD sum rule analysis for the Lambda(1405) and the Sigma(1620). Using the I=0 and I=1 multiquark sum rules we predict their masses.
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…
We have carried out a study of the $\gamma ~ p \rightarrow p K^{+} K^{*-} (K^{*-} \rightarrow K^{-} \pi^{0}) $, $ \gamma ~p \rightarrow p K^{+} K^{*-} ( K^{*-} \rightarrow \bar{K}^{0} \pi^{-} )$ and $ \gamma ~p \rightarrow K^{+} K^{-}p$…
The mechanism for the formation of the $\Lambda(1405)$ resonance is studied in a chiral quark model that includes quark-meson as well as contact (four point) interactions. The negative-parity $S$-wave scattering amplitudes for strangeness…
This work presents technical details of determining the finite-volume energy spectra for the scattering amplitude of the coupled-channel $\pi\Sigma - \bar{K}N$ from lattice QCD data. The importance of reliably extracting such spectra lies…
We analyze the $f_0(500)$ state generated as a pole of $\pi\pi$ scattering within unitarized low-energy effective theories at finite temperature. First, we report on the $\sigma$ self-energy in the LSM, which is used as a benchmark in order…
We complete the recalculation of the available two-loop expressions for the reaction \gamma\gamma->\pi\pi in the framework of chiral perturbation theory. Here, we present the results for charged pions. The cross section and the values of…
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…
The electroproduction of $K^+ \Lambda$ (1405) was studied by analyzing the E1F data set collected in Hall B at Jefferson Lab. The analysis utilized the decay channel $\Sigma^+ \pi^-$ of the $\Lambda$ (1405) and $p \pi^0$ of the $\Sigma^+$.…
With an effective Lagrangian approach, we analyze the $K^-p\to \pi^0\Sigma^0$ reaction to study the $\Lambda$ hyperon resonances by fitting the Crystal Ball data on differential cross sections and $\Sigma^0$ polarization with the…