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Dias, J. M., Toledo, G., Roca, L., & Oset, E. (2021). Unveiling the K-1(1270) double-pole structure in the (B)over-bar -> J/psi rho(K)over-bar and (B)over-bar -> J/psi(K)over-bar*pi decays. Phys. Rev. D, 103(11), 116019–13pp.
Abstract: By looking at the pseudoscalar-vector meson spectra in the (B) over bar -> J/psi rho(K) over bar and (B) over bar -> J/psi(K) over bar*pi weak decays, we theoretically investigate the double-pole structure of the K-1 (1270) resonance by using the chiral unitary approach to account for the final-state interactions between the pseudoscalar (P) and vector (V) mesons. The K-1 (1270) resonance is dynamically generated through these interactions in coupled channels and influences the shape of the invariant mass distributions under consideration. We show how these shapes are affected by the K-1 (1270) double-pole structure to confront the results from our model with future experiments that might investigate the PV spectra in these decays.
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Ikeno, N., Dias, J. M., Liang, W. H., & Oset, E. (2019). chi(c1) decays into a pseudoscalar meson and a vector-vector molecule. Phys. Rev. D, 100(11), 114011–7pp.
Abstract: We evaluate ratios of the chi(c1) decay rates to eta (eta', K-) and one of the f(0) (1370), f(0) (1710), f(2) (1270), f(2)'(1525), K-2*(1430) resonances, which in the local hidden gauge approach are dynamically generated from the vector-vector interaction. With the simple assumption that the chi(c1) is a singlet of SU(3), and the input from the study of these resonances as vector-vector molecular states, we describe the experimental ratio B(chi(c1)-> eta f(2) (1270))/B(chi(c1) -> eta'f(2)' (1525)) and make predictions for six more ratios that can be tested in future experiments.
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Dias, J. M., Navarra, F. S., Nielsen, M., & Oset, E. (2016). f(0)(980) production in D-s(+)-> pi(+) pi(+) pi(-) and D-s(+) -> pi(+) K+ K- decays. Phys. Rev. D, 94(9), 096002–8pp.
Abstract: We study the D-s(+)-> pi(+) pi(+) pi(-) and D-s(+) -> pi(+) K+ K- decays adopting a mechanism in which the D-s(+) meson decays weakly into a pi+ and a q (q) over bar component, which hadronizes into two pseudoscalar mesons. The final state interaction between these two pseudoscalar mesons is taken into account by using the chiral unitary approach in coupled channels, which gives rise to the f(0)(980) resonance. Hence, we obtain the invariant mass distributions of the pairs pi(+) pi(-) and K+ K- after the decay of that resonance and compare our theoretical amplitudes with those available from the experimental data. Our results are in a fair agreement with the shape of these data, within large experimental uncertainty, and a f(0)(980) signal is seen in both the pi(+) pi(-) and K+ K- distributions. Predictions for the relative size of pi(+) pi(-) and K+ K- distributions are made.
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Debastiani, V. R., Dias, J. M., Liang, W. H., & Oset, E. (2018). Molecular Omega(c) states generated from coupled meson-baryon channels. Phys. Rev. D, 97(9), 094035–11pp.
Abstract: We have investigated Omega(c) states that are dynamically generated from the meson-baryon interaction. We use an extension of the local hidden gauge to obtain the interaction from the exchange of vector mesons. We show that the dominant terms come from the exchange of light vectors, where the heavy quarks are spectators. This has as a consequence that heavy quark symmetry is preserved for the dominant terms in the (1/m(Q)) counting, and also that the interaction in this case can be obtained from the SU(3) chiral Lagrangians. We show that for a standard value for the cutoff regulating the loop, we obtain two states with J(P) = 1/2(-) and two more with J(P) = 3/2(-), three of them in remarkable agreement with three experimental states in mass and width. We also make predictions at higher energies for states of vector-baryon nature.
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Debastiani, V. R., Dias, J. M., Liang, W. H., & Oset, E. (2018). Omega(-)(b) -> (Xi(+)(c) K-)pi(-) decay and the Omega(c) states. Phys. Rev. D, 98(9), 094022–8pp.
Abstract: We study the weak decay Omega(-)(b) -> (Xi(+)(c) K-)pi(-), in view of the narrow Omega(c) states recently measured by the LHCb Collaboration and later confirmed by the Belle Collaboration. The Omega(c) (3050) and Omega(c) (3090) are described as meson-baryon molecular states, using an extension of the local hidden gauge approach in coupled channels. We investigate the Xi D, Xi(c)(K) over bar, and. Xi '(c) (K) over bar invariant mass distributions making predictions that could be confronted with future experiments, providing useful information that could help determine the quantum numbers and nature of these states.
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Dias, J. M., Debastiani, V. R., Xie, J. J., & Oset, E. (2018). Doubly charmed Xi(cc) molecular states from meson-baryon interaction. Phys. Rev. D, 98(9), 094017–11pp.
Abstract: Stimulated by the new experimental LHCb findings associated with the Omega(c) states, some of which we have described in a previous work as being dynamically generated through meson-baryon interaction, we have extended this approach to make predictions for new Xi(cc) molecular states in the C = 2, S = 0, and I = 1/2 sector. These states manifest themselves as poles in the solution of the Bethe-Salpeter equation in coupled channels. The kernels of this equation were obtained using general Lagrangians coming from the hidden local gauge symmetry or massive Yang-Mills theory, and the interactions are dominated by the exchange of light vector mesons. The extension of this approach to the heavy sector stems from the realization that the dominant interaction corresponds to having the heavy quarks as spectators, which implies the preservation of the heavy quark symmetry. As a result, we get several states: three states from the pseudoscalar meson-baryon interaction with J(P) = 1/2(-), and masses around 3840, 4080 and 4090 MeV, and two at 3920 and 4150 MeV for J(P) = 3/2(-). Furthermore, from the vector meson-baryon interaction we get three states degenerate with J(P) 1/2(-) and 3/2(-) from 4220 MeV to 4290 MeV, and two more states around 4280 and 4370 MeV, degenerate with J(P) = 1/2(-), 3/2(-), and 5/2(-).
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Dias, J. M., Debastiani, V. R., Roca, L., Sakai, S., & Oset, E. (2017). Binding of the BD(D)over-bar and BDD systems. Phys. Rev. D, 96(9), 094007–6pp.
Abstract: We study theoretically the BD (D) over bar and BDD systems to see if they allow for possible bound or resonant states. The three-body interaction is evaluated implementing the fixed center approximation to the Faddeev equations which considers the interaction of a D or (D) over bar particle with the components of a BD cluster, previously proved to form a bound state. We find an I(J(P)) = 1/2(0(-)) bound state for the BD (D) over bar system at an energy around 8925-8985 MeV within uncertainties, which would correspond to a bottom hidden-charm meson. In contrast, for the BDD system, which would be bottom double-charm and hence manifestly exotic, we have found hints of a bound state in the energy region 8935-8985 MeV, but the results are not stable under the uncertainties of the model, and we cannot assure, nor rule out, the possibility of a BDD three-body state.
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Dias, J. M., Aceti, F., & Oset, E. (2015). Study of B<(B)over bar>* and B*<(B)over bar>* interactions in I=1 and relationship to the Z(b)(10610), Z(b)(10650) states. Phys. Rev. D, 91(7), 076001–14pp.
Abstract: We use the local hidden gauge approach in order to study the B (B) over bar* and B*(B) over bar* interactions for isospin I = 1. We show that both interactions via one light meson exchange are not allowed by the Okubo-ZweigIizuka rule and, for that reason, we calculate the contributions due to the exchange of two pions, interacting and noninteracting among themselves, and also due to the heavy vector mesons. Then, to compare all these contributions, we use the potential related to the heavy vector exchange as an effective potential corrected by a factor which takes into account the contribution of the other light meson exchanges. In order to look for poles, this effective potential is used as the kernel of the Bethe-Salpeter equation. As a result, for the B (B) over bar* interaction we find a loosely bound state with mass in the range 10587-10601 MeV, very close to the experimental value of the Z(b)(10610) reported by the Belle Collaboration. For the B*(B) over bar* case, we find a cusp at 10650 MeV for all spin J = 0, 1, 2 cases.
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Dias, J. M., Yu, Q. X., Liang, W. H., Sun, Z. F., Xie, J. J., & Oset, E. (2020). Xi(bb) and Omega(bbb) molecular states. Chin. Phys. C, 44(6), 064101–8pp.
Abstract: Using the vector exchange interaction in the local hidden gauge approach, which in the light quark sector generates the chiral Lagrangians and has produced realistic results for Omega(C), Xi(c), Xi(b) and the hidden charm pentaquark states, we study the meson-baryon interactions in the coupled channels that lead to the Xi(bb) and Omega(bbb) excited states of the molecular type. We obtain seven states of the Xi(bb) type with energies between and MeV, and one Omega(bbb) state at MeV.
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Dias, J. M., Roca, L., & Sakai, S. (2018). Prediction of new states from D(*)B(*)(B)over-bar(*) three-body interactions. Phys. Rev. D, 97(5), 056019–8pp.
Abstract: We study three-body systems composed of D(*), B(*), and (B) over bar(*) in order to look for possible bound states or resonances. In order to solve the three-body problem, we use the fixed center approach for the Faddeev equations considering that the B*(B) over bar*(B (B) over bar) are clusterized systems, generated dynamically, which interact with a third particle D((D) over bar) whose mass is much smaller than the two-body bound states forming the cluster. In the DB*(B) over bar*, D*B*(B) over bar*, DB (B) over bar, and D*B (B) over bar systems with I = 1/2, we found clear bound state peaks with binding energies typically a few tens MeV and more uncertain broad resonant states about ten MeV above the threshold with widths of a few tens MeV.
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