Abstract: A model is developed to describe odd-parity baryon resonances generated dynamically through a unitary baryon-meson coupled-channels approach. The scheme applies to channels with light- and/or heavy-quark content. Distinct features of the model are that i) the interaction is an S-wave contact one, ii) it reduces to the SU(3) Weinberg-Tomozawa Hamiltonian when light pseudoscalar mesons are involved, thus respecting chiral symmetry, iii) spin-flavor is preserved in the light-quark sector, and iv) heavy-quark spin symmetry is fulfilled in the heavy-quark sector. In particular, baryon-meson states with different content in c or in (c) over bar do not mix. The model is a minimal one and it contains no free parameters. In this work, we focus on baryon resonances with hidden charm (at least one (c) over bar and one c quark). We analyze several possible sectors and, for the sector with zero net charm, we write down the most general Lagrangian consistent with SU(3) and heavy-quark spin symmetry. We explicitly study the N and Delta states, which are produced from the S-wave interaction of pseudoscalar and vector mesons with 1/2(+) and 3/2(+) baryons within the charmless and strangeless hidden-charm sector. We predict seven odd-parity N-like and five Delta-like states with masses around 4 GeV, most of them as bound states. These states form heavy-quark spin multiplets, which are almost degenerate in mass. The predicted new resonances definitely cannot be accommodated by quark models with three constituent quarks and they might be looked for in the forthcoming PANDA experiment at the future FAIR facility.

Abstract: We investigate the structure and formation of charmed meson--nucleus systems, with the aim of understanding the charmed meson-nucleon interactions and the properties of the charmed mesons in the nuclear medium. The (D) over bar mesic nuclei are of special interest, since they have tiny decay widths due to the absence of strong decays for the (D) over barN pair. Employing an effective model for the (D) over barN and DN interactions and solving the Klein-Gordon equation for (D) over bar and D in finite nuclei, we find that the D0-11B system has 1s and 2p mesic nuclear states and that the D0-11B system binds in a 1s state. In view of the forthcoming experiments by the PANDA and CBM Collaborations at the future FAIR facility and the J-PARC upgrade, we calculate the formation spectra of the [(D) over bar B--11] and [D-0-B-11] mesic nuclei for an antiproton beam on a C-12 target. Our results suggest that it is possible to observe the 2p D- mesic nuclear state with an appropriate experimental setup.

Abstract: The anti-D meson self-energy is evaluated self-consistently, using unitarized coupled-channel theory, by computing the in-medium meson-baryon T matrix in the C = -1, S = 0 sector. The heavy pseudo-scalar and heavy vector mesons, (D) over bar and (D) over bar*, are treated on equal footing as required by heavy-quark spin symmetry. Results for energy levels and widths of (D) over bar (-) mesic atoms in C-12, Ca-40, Sn-118, and Pb-208 are presented. The spectrum contains states of atomic and of nuclear types for all nuclei. (D) over bar (0)-nucleus bound states are also obtained. We find that, after electromagnetic and nuclear cascade, these systems end up with the (D) over bar bound in the nucleus, either as a meson or as part of an exotic (D) over barN (pentaquark) loosely bound state.