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Ikeno, N., Liang, W. H., Toledo, G., & Oset, E. (2022). Interpretation of the Omega(c) -> pi(+) Omega(2012) -> pi(+) ((K)over-bar Xi) relative to Omega(c) -> pi(+) (K)over-bar Xi from the Omega (2012) molecular perspective. Phys. Rev. D, 106(3), 034022–10pp.
Abstract: We present a mechanism for Omega(c) -> pi(+)Omega (2012) production through an external emission Cabibbo favored weak decay mode, where the Omega (2012) is dynamically generated from the interaction of (K) over bar Xi(*) (1530) and eta Omega, with (K) over bar Xi as the main decay channel. The Omega (2012) decays later to (K) over bar Xi. in this picture, with results compatible with Belle data. As a consequence, one can evaluate the direct decay Omega(0)(c) -> pi K-+(-)Xi(0) and the decay Omega(0)(c) -> pi(+)(K) over bar Xi* pi(+)eta Omega with direct couplings of (K) over bar Xi* and eta Omega to K-Xi(0). We show that, within uncertainties and using data from a recent Belle measurement, all three channels account for about (12-20)% of the total Omega(c) -> pi K-+(-)Xi(0) decay rate. The consistency of the molecular picture with all the data is established by showing that Omega(c) -> Xi(0)(K) over bar*(0) -> Xi K-0(-)pi(+) and Omega(c) -> pi(+)Omega* -> pi K-+(-Xi 0) account for about 85% of the total Omega(c) -> pi K-+(-)Xi(0).
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Wang, W. F., Feijoo, A., Song, J., & Oset, E. (2022). Molecular Omega(ce), Omega(bb), and Omega(bc) states. Phys. Rev. D, 106(11), 116004–14pp.
Abstract: We study the interaction of meson-baryon coupled channels carrying quantum numbers of a Omega(ce), Omega(bb), and Omega(bc) presently under investigation by the LHCb Collaboration. The interaction is obtained from an extension of the local hidden gauge approach to the heavy quark sector that has proved to provide accurate results compared to experiment in the case of Omega(c), Xi(c) states and pentaquarks, P-c and P-cs. We obtain many bound states, with small decay widths within the space of the chosen coupled channels. The spin-parity of the states are J(P) = 1/2(-) for coupled channels of pseudoscalar-baryon (1/2(+)), J(P) = 3/2(-) for the case of pseudoscalar-baryon (3/2(+)), J(P) = 1/2(-), 3/2(-) for the case of vector-baryon (1/2(+)) and J(P) = 1/2(-), 3/2(-). 5/2(-) for the vector- baryon (3/2(+)) channels. We look for poles of the states and evaluate the couplings to the different channels. The couplings obtained for the open channels can serve as a guide to see in which reaction the obtained states are more likely to be observed.
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Song, J., Feijoo, A., & Oset, E. (2022). Role of meson interactions in the D-s(+) -> pi(+) pi(+) pi(-) eta decay. Phys. Rev. D, 106(7), 074027–20pp.
Abstract: We perform a theoretical study of the D-s(+) ->pi(+)pi(+)pi(-)eta decay. We look first at the basic D-s(+) decay at the quark level from external and internal emission. Then we hadronize a pair or two pairs of q (q) over bar states to have mesons at the end. Posteriorly the pairs of mesons are allowed to undergo final state interaction, by means of which the a(0)(980), f(0)(980), a(1)(1260), and b(1)(1235) resonances are dynamically generated. The G parity is used as a filter of the possible channels, and from those with negative G parity only the ones that can lead to pi(+)pi(+)pi(-)eta at the final state are kept. Using transition amplitudes from the chiral unitary approach that generates these resonances and a few free parameters, we obtain a fair reproduction of the six mass distributions reported in the BESIII experiment.
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Wang, E., Liang, W. H., & Oset, E. (2021). Analysis of the e(+)e(-) -> J/psi D(D)over-bar reaction close to the threshold concerning claims of a chi(c0)(2P) state. Eur. Phys. J. A, 57(1), 38–9pp.
Abstract: We analyze the D (D) over bar mass distribution from a recent Belle experiment on the e(+)e(-) -> J/.D (D) over bar reaction, and show that the mass distribution divided by phase sp(c)e does not have a clear peak above the D (D) over bar threshold that justifies the experimental claim of chi(c0)(2P) state from those data. Then we use a unitary formalismwith coupled channels D+ D-, D-0 (D) over bar (0), D-s(D) over bar (s), and eta eta, with some of the interactions taken from a theoretical model, and use the data to fix other parameters. We then show that, given the poor quality of the data, we can get different fits leading to very different D (D) over bar amplitudes, some of them supporting a D (D) over bar bound state and others not. The main conclusion is that the claim for the chi(c0)(2P) state, already included in the PDG, is premature, but refined data can provide very valuable information on the D (D) over bar scattering amplitude. As side effects, we warn about the use of a Breit-Wigner amplitude parameterization close to threshold, and show that the D-s(D) over bar (s) channel plays an important role in this reaction.
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Roca, L., & Oset, E. (2021). Scalar resonances in the D+ -> K-K+K+ decay. Phys. Rev. D, 103(3), 034020–9pp.
Abstract: We study theoretically the resonant structure of the double Cabibbo suppressed D+ -> K-K+K+ decay. We start from an elementary production diagram, considered subleading in previous approaches, which cannot produce a final K-K+ pair at the tree level but which we show to be able to provide the strength of the decay through final meson-meson state interaction. The different meson-meson elementary productions are related through SU(3), and the final rescattering is implemented from a suitable implementation of unitary extensions of chiral perturbation theory, which generate dynamically the scalar resonances1 f(0)(980) and a(0)(980). We obtain a good agreement with recent experimental data from the LHCb Collaboration with a minimal freedom in the fit and show the dominance of the a(0)(980) contribution close to the threshold of the K-K+ spectrum.
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