Model-independent determination of the compositeness of near-threshold quasibound states

We study the compositeness of near-threshold states to clarify the internal structure of exotic hadron candidates. Within the framework of effective field theory, we extend the Weinberg's weak-binding relation to include the nearby CDD (Castillejo-Dalitz-Dyson) pole contribution with the help of the Pade approximant. Finally, using the extended relation, we conclude that the CDD pole contribution to the Lambda(1405) baryon in the Kbar N amplitude is negligible.Comment: 5 pages, Proceedings of the 14th International Conference on Meson-Nucleon Physics and the Structure of the Nucleon (MENU2016), July 25-30, 2016, Kyoto, Japa

Generalized weak-binding relations of compositeness in effective field theory

We study the compositeness of near-threshold states to investigate the internal structure of exotic hadron candidates. Within the framework of effective field theory, Weinberg's weak-binding relation is extended to more general cases by easing several preconditions. First, by evaluating the contribution from the decay channel, we obtain the generalized relation for unstable quasibound states. Next, we generalize the relation to include the nearby CDD (Castillejo-Dalitz-Dyson) pole contribution with the help of the Pade approximant. The validity of the estimation with the generalized weak-binding relations is examined by numerical calculations. The method to systematically evaluate the error in the weak-binding relation is presented. Finally, by applying the extended relation to Lambda(1405), f0(980) and a0(980), we discuss their internal structure, in comparison with other approaches.Comment: 46 pages, 12 figures, published versio

New insights into the nature of the Λ(1380)\Lambda(1380) and Λ(1405)\Lambda(1405) resonances away from the SU(3) limit

Starting from the SU(3) limit, we consider the nature of the dynamically generated resonances $\Lambda(1380)$, $\Lambda(1405)$ and $\Lambda(1680)$ as the pion and kaon masses are tuned to their physical values. We show that the accidental symmetry of the two octets due to the leading order Weinberg-Tomozawa term is broken by the next-to-leading order terms. Most interestingly, we observe an interchange of the two trajectories of the $\Lambda(1380)$ and the $\Lambda(1405)$ away from the SU(3) limit at next-to-leading order. This remarkable phenomenon can be investigated using lattice QCD calculations that start from the SU(3) limit.Comment: 11 pages, 4 figure

Evidence of a p-ϕ\phi bound state

The existence of a nucleon-$\phi$ (N-$\phi$) bound state has been subject of theoretical and experimental investigations for decades. In this letter a re-analysis of the p-$\phi$ correlation measured at the LHC is presented, using as input recent lattice calculations of the N-$\phi$ interaction in the spin 3/2 channel obtained by the HAL QCD collaboration. A constrained fit of the experimental data allows to determine the spin 1/2 channel of the p-$\phi$ interaction with evidence of the formation of a p-$\phi$ bound state. The scattering length and effective range extracted from the spin 1/2 channel are $f_0^{(1/2)}=(-1.47^{+0.44}_{-0.37}(\mathrm{stat.})^{+0.14}_{-0.17}(\mathrm{syst.})+i\cdot0.00^{+0.26}_{-0.00}(\mathrm{stat.})^{+0.15}_{-0.00}(\mathrm{syst.}))$ fm and $d_0^{(1/2)}=(0.37^{+0.07}_{-0.08}(\mathrm{stat.})^{+0.03}_{-0.03}(\mathrm{syst.})+i\cdot~0.00^{+0.00}_{-0.02}(\mathrm{stat.})^{+0.00}_{-0.01}(\mathrm{syst.}))$ fm, respectively. The corresponding binding energy is estimated to be in the range $14.7-56.6$ MeV. This is the first experimental evidence of a p-$\phi$ bound state

Femtoscopic study of coupled-channel baryon-baryon interactions with S=−2S=-2

Particles and Nuclei International Conference - PANIC2021, 5 - 10 September, 2021, OnlineThe correlation functions of pΞ− and ΛΛ pairs from pp and pA collisions are studied in the coupled-channel framework using the NΞ-ΛΛ coupled-channel baryon-baryon potentials obtained in the lattice QCD calculation at almost physical quark masses. The pΞ− correlation function is calculated to be significantly enhanced from the pure Coulomb case, while the ΛΛ correlation function is slightly enhanced from that of the pure fermion quantum statistics. These features reflect the large and small scattering lengths in the pΞ− and ΛΛ channels in magnitude, and agree with the observed data by the ALICE collaboration. The agreement confirms the S = −2 baryon-baryon potentials from lattice QCD