We study the dependence on the quark mass of the compositeness of the lowest-lying odd parity hyperon states. Thus, we pay attention to $Lambda-$like states in the strange, charm and beauty, sectors which are dynamically generated using a unitarized
meson-baryon model. In the strange sector we use an SU(6) extension of the Weinberg-Tomozawa meson-baryon interaction, and we further implement the heavy-quark spin symmetry to construct the meson-baryon interaction when charmed or beauty hadrons are involved. In the three examined flavor sectors, we obtain two $J^P=1/2^-$ and one $J^P=3/2^-$ $Lambda$ states. We find that the $Lambda$ states which are bound states (the three $Lambda_b$) or narrow resonances (one $Lambda(1405)$ and one $Lambda_c(2595)$) are well described as molecular states composed of $s$-wave meson-baryon pairs. The $frac{1}{2}^-$ wide $Lambda(1405)$ and $Lambda_c(2595)$ as well as the $frac{3}{2}^-$ $Lambda(1520)$ and $Lambda_c(2625)$ states display smaller compositeness and so they would require new mechanisms, such as $d$-wave interactions.
We study odd-parity baryonic resonances with one heavy and three light flavors, dynamically generated by meson-baryon interactions. Special attention is paid to Heavy Quark Spin Symmetry (HQSS), hence pseudoscalar and vector mesons and baryons with J
^P = 1/2+ and 3/2+ are considered as constituent hadrons. For the hidden-charm sector (N-c-quarks = N-c-antiquarks = 1), the meson-baryon Lagrangian with Heavy Flavor Symmetry is constructed by a minimal extension of the SU(3) Weinberg-Tomozawa (WT) Lagrangian to fulfill HQSS, such that not new parameters are needed. This interaction can be presented in different formal ways: as a Field Lagrangian, as Hadron creation-annihilation operators, as SU(6)xHQSS group projectors and as multichannel matrices. The multichannel Bethe-Salpeter equation is solved for odd-parity light baryons, hidden-charm N and Delta and Beauty Baryons (Lambda-b). Results of calculations with this model are shown in comparison with other models and experimental values for baryonic resonances.
We use a consistent SU(6) extension of the meson-baryon chiral Lagrangian within a coupled channel unitary approach in order to calculate the T-matrix for meson-baryon scattering in s-wave. The building blocks of the scheme are the pion and nucleon o
ctets, the rho nonet and the Delta decuplet. We identify poles in this unitary T-matrix and interpret them as resonances. We study here the non exotic sectors with strangeness S=0,-1,-2,-3 and spin J=1/2, 3/2 and 5/2. Many of the poles generated can be associated with known N, Delta, Sigma, Lambda and Xi resonances with negative parity. We show that most of the low-lying three and four star odd parity baryon resonances with spin 1/2 and 3/2 can be related to multiplets of the spin-flavor symmetry group SU(6). This study allows us to predict the spin-parity of the Xi(1620), Xi(1690), Xi(1950), Xi(2250), Omega(2250) and Omega(2380) resonances, which have not been determined experimentally yet.
We study charmed baryon resonances that are generated dynamically from a coupled-channel unitary approach that implements heavy-quark symmetry. Some states can already be identified with experimental observations, such as $Lambda_c(2595)$, $Lambda_c(
2660)$, $Sigma_c(2902)$ or $Lambda_c(2941)$, while others need a compilation of more experimental data as well as an extension of the model to include higher order contributions. We also compare our model to previous SU(4) schemes.
We study charmed baryon resonances which are generated dynamically within a unitary meson-baryon coupled channel model that treats the heavy pseudoscalar and vector mesons on equal footing as required by heavy-quark symmetry. It is an extension of re
cent SU(4) models with t-channel vector meson exchanges to a SU(8) spin-flavor scheme, but differs considerably from the SU(4) approach in how the strong breaking of the flavor symmetry is implemented. Some of our dynamically generated states can be readily assigned to recently observed baryon resonances, while others do not have a straightforward identification and require the compilation of more data as well as an extension of the model to d-wave meson-baryon interactions and p-wave coupling in the neglected s- and u-channel diagrams. Of several novelties, we find that the Lambda_c(2595), which emerged as a ND quasi-bound state within the SU(4) approaches, becomes predominantly a ND* quasi-bound state in the present SU(8) scheme.
Consistent SU(6) and SU(8) spin-flavor extensions of the SU(3) flavor Weinberg-Tomozawa (WT) meson-baryon chiral Lagrangian are constructed, which incorporate vector meson degrees of freedom. In the charmless sector, the on-shell approximation to the
Bethe-Salpeter (BS) approach successfully reproduces previous SU(3) WT results for the lowest-lying s--wave negative parity baryon resonances. It also provides some information on the dynamics of heavier ones and of the lightest d-wave negative parity resonances, as e.g. the Lambda(1520). For charmed baryons the scheme is consistent with heavy quark symmetry, and our preliminary results in the strangeness-less charm C=+1 sector describe the main features of the three-star J^P=1/2^- Lambda_c(2595) and J^P=3/2^- Lambda_c(2625) resonances. We also find a second broad J^P=1/2^- state close to the Lambda_c(2595)
