We discuss several aspects of the Λ(1405) resonance in relation to the recent theoretical developments in chiral dynamics. We derive an effective single-channel K̄N interaction based on chiral SU(3) coupled-channel approach, emphasizing the important role of the πΣ channel and the structure of the Λ(1405) in K̄N phenomenology. In order to clarify the structure of the resonance, we study the behav...

We investigate the structure of the Λ(1405) resonance and K̄N phenomenology in the perspective of chiral SU(3) dynamics. Utilizing the chiral coupled-channel approach which well describes the K̄N scattering observable, we perform three different analyses to clarify the structure of the Λ(1405) resonance. The results consistently indicate the meson-baryon molecule picture of the Λ(1405). We argue ...

S-wave Kp scattering into various channels near threshold are analyzed in heavybaryon chiral perturbation theory with Λ(1405) introduced as an independent field. This is the approach that predicted the critical density 2 <∼ ρc/ρ0 <∼ 3 for negatively charged kaon condensation. We show that chiral perturbation expansion treating the Λ(1405) as elementary is consistent with all threshold data incl...

The scattering of antikaons with nucleons is studied in the nuclear environment. Describing the Λ(1405) as a K− proton bound state, we find, that due to the Pauli blocking of intermediate states, the mass of the Λ(1405) is shifted upwards in energy, above the K− proton threshold and and its width is somewhat broadened. As a consequence the s-wave K−–nucleon scattering length turns attractive at...

Motivated by the recently constructed interpolation field for S11(1535), we propose a new interpolating field for Λ(1405). Using this current, we calculate the mass of Λ(1405) based on the conventional QCD sum rule analysis. By calculating the Wilson coefficients up to dimension 8 operators and taking into account the mass corrections from s-quark, we find the calculated mass of Λ(1405) to be v...

Starting from 2003, a large number of the so-called exotic hadrons, such as $X(3872)$ and $D_{s0}^*(2317)$, were discovered experimentally. Since then, understanding nature these states has been central issue both theoretically As many are located close to two hadron thresholds, they believed be molecular or at least contain components. We argue that if indeed states, in way deuteron is bound s...

We calculate the shape of the ππ and ¯ K N invariant mass distributions in the b → J/ψ π and b → J/ψ ¯ K N decays that are dominated by the (1405) resonance. The weak interaction part is the same for both processes and the hadronization into the different meson–baryon channels in the final state is given by symmetry arguments. The most important feature is the implementation of the meson–baryon...