Coupled $\Lambda N-\Sigma N$ and $\Lambda NN-\Sigma NN$ systems and hyperon-nucleon interactions

The non--mesonic weak decay of double--$\Lambda$ hypernuclei is studied within a microscopic diagrammatic approach. Besides the nucleon--induced mechanism, $\Lambda N\to nN$, widely studied in single--$\Lambda$ hypernuclei, additional hyperon--induced mechanisms, $\Lambda \Lambda\to \Lambda n$, $\Lambda \Lambda\to \Sigma^0 n$ and $\Lambda \Lambda\to \Sigma^-p$, are accessible in double--$\Lambda$ hypernuclei and are investigated here. As in previous works on single--$\Lambda$...

The spectrum of $\Lambda$ and $\Sigma$ excitations is reviewed taking into account (nearly) all hyperon resonances which were seen in early analyses or in one of the recent partial-wave analyses. The spectrum is compared with the old Isgur-Karl model and the Bonn model. These models allows us to discuss the SU(3) structure of the observed resonances. The SU(3) decomposition is compared with SU(6) relations between the different decay modes. Seven $\Lambda$ states are proposed...

In this work we present the study of $p\Lambda$ and $pp\Lambda$ scattering processes using femtoscopic correlation functions. This observable has been recently used to access the low-energy interaction of hadrons emitted in the final state of high-energy collisions, delivering unprecedented precision information of the interaction among strange hadrons. The formalism for particle pairs is well established and it relates the measured correlation functions with the scattering w...

The spectrum of hypernuclear trios composed of a $\Lambda$ baryon and two nucleons is the subject of an ongoing experimental campaign, aiming to study the interaction of the $\Lambda$ particle with a neutron, and the 3-body $\Lambda$-nucleon-nucleon force. In this manuscript we utilize baryonic effective field theory at leading order, constrained to reproduce the available low energy light hypernuclear data, to study the continuum spectrum of such hypernuclear trios. Using th...

Heavy-ion collisions provide a unique opportunity to explore nucleon-hyperon (N-Y) interactions through two-particle correlations. The $p-\Lambda$ and $d-\Lambda$ correlations shed light on both N-Y two-body and N-N-Y three-body interactions, which is crucial for understanding neutron star properties. We present the high precision measurement of $p-\Lambda$ and the first measurement of $d-\Lambda$ correlation with $\sqrt{s_{_{\rm NN}}}=$ 3 GeV Au+Au collisions at STAR. Using ...

We present our recent studies on hyperon-nucleon (YN) interactions in the strangeness S=-1 that $p\Lambda, \Sigma^0 p$ and $\Sigma^+ n$, by extracting corresponding potentials through Nambu-Bethe-Salpeter wave functions. We calculate $\Lambda N$ and $\Sigma N$ potentials in the isospin I=3/2 channel, using the $N_f=2+1$ gauge configurations generated by PACS-CS collaboration and employing an improved method to obtain potentials in lattice QCD simulations. For the $^1S_0$ chan...

In this work, we outline the findings of our recent study of the properties of $N^*(1895)$ and its consequential impacts on the cross sections of the photoproduction of $\Lambda(1405)$. Further, we discuss the possibility of the existence of an isovector state, with the mass similar to $\Lambda(1405)$, which we refer to as $\Sigma(1400)$. With the idea of motivating experimental investigations of $\Sigma(1400)$, we have studied its photoproduction process and determined the r...

Over the last decade, conflicting values of the hypertriton ${}_{\Lambda}^3\mathrm{H}$ lifetime $\tau({}_{\Lambda}^3\mathrm{H})$ were extracted from relativistic heavy-ion (RHI) collision experiments, ranging from values compatible with the free-$\Lambda$ lifetime $\tau_\Lambda$-as expected naively for a very weakly bound $\Lambda$ in ${}_{\Lambda}^3\mathrm{H}$-to lifetimes as short as $\tau({}_{\Lambda}^3\mathrm{H}) \approx (0.4-0.7)\,\tau_\Lambda$. In a recent work [1] we s...

A study of light $\Lambda$ hypernuclei in chiral effective field theory is presented. For the first time chiral $\Lambda$NN and $\Sigma$NN three-body forces are included consistently. The calculations are performed within the no-core shell model. Results for the separation energies of the hypernuclei $^3_{\Lambda}\mathrm{H}$, $^4_{\Lambda}\mathrm{H}$/$^4_{\Lambda}\mathrm{He}$, $^5_{\Lambda}\mathrm{He}$, and $^7_{\Lambda}\mathrm{Li}$ are given. It is found that the experimenta...

We present a new model for the hyperon-nucleon (Lambda N, Sigma N) interaction, derived within the meson exchange framework. The model incorporates the standard one boson exchange contributions of the lowest pseudoscalar and vector meson multiplets with coupling constants fixed by SU(6) symmetry relations. In addition - as the main feature of the new model - the exchange of two correlated pions or kaons, both in the scalar-isoscalar (sigma) and vector-isovector (rho) channels...