Ikeno, N., Molina, R., & Oset, E. (2022). Zcs states from the D*s over bar D* and J=psi K* coupled channels: Signal in B+ -> J=psi phi K+ decay. Phys. Rev. D, 105(1), 014012–13pp.
Abstract: We study the D*s over bar D* system in connection with the J=psi K* in coupled channels and observe that, within reasonable values of the cutoff used to regularize the loops, the system does not develop a bound state. However, the JP = 2+ channel has enough attraction to create a strong cusp structure that shows up in the J=psi K+ invariant mass distribution in the B+ -> J=psi phi K+ decay at the D*s over bar D* threshold. Such structure is results should stimulate further measurements around this region, given the fact that cusp effects provide as valuable information on hadron dynamics as resonances themselves.
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Feijoo, A., Liang, W. H., & Oset, E. (2021). (DD0)-D-0 pi(+) mass distribution in the production of the T-cc exotic state. Phys. Rev. D, 104(11), 114015–7pp.
Abstract: We perform a unitary coupled channel study of the interaction of the D*D-+(0), D*D-0(+) channels and find a state barely bound, very close to isospin I = 0. We take the experimental mass as input and obtain the width of the state and the (DD0 pi-)-D-0+ mass distribution. When the mass of the T-cc state quoted in the experimental paper from raw data is used, the width obtained is of the order of the 80 keV, small compared to the value given in that work. Yet, when the mass obtained in an analysis of the data considering the experimental resolution is taken, the width obtained is about 43 keV and both the width and the (DD0 pi+)-D-0 mass distribution are in remarkable agreement with the results obtained in that latter analysis.
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Roca, L., Liang, W. H., & Oset, E. (2022). Inconsistency of the data on the K-1(1270) -> pi K-0*(1430) decay width. Phys. Lett. B, 824, 136827–3pp.
Abstract: We show, using the same Lagrangian for the K-1(1270) -> pi K-0*(1430) and K-0*(1430) -> K-1 (1270)pi decays, that the present PDG data on the partial decay width of K-1 (1270) -> pi K-0*(1430) implies a width for K-0*(1430) -> K-1 (1270)pi decay which is about one order of magnitude larger than the total K-0*(1430) width. A discussion on this inconsistency is done, stressing its relationship to the existence of two K-1(1270) states obtained with the chiral unitary theory, which are not considered in the experimental analyses of K pi pi data.
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Lin, J. X., Li, J. T., Jiang, S. J., Liang, W. H., & Oset, E. (2021). The D-s(+) -> a(0)(980)e(+)nu(e) reaction and the a(0)(980) – f(0)(980) mixing. Eur. Phys. J. C, 81(11), 1017–8pp.
Abstract: We perform a study of the D-s(+) -> a(0)(980) (f(0)(980))e(+)nu(e) reactions investigating the different sources of isospin violation which make the production of the a0(980) possible. We find that loops involving kaons in the production mechanism provide a source of isospin violation since they do not cancel due to the different mass of charged and neutral kaons, but we also find that the main source comes from the breaking of isospin in the meson-meson transition T matrices, which contain information on the nature of the low lying scalar mesons. The reaction is thus very sensitive to the nature of the a(0)(980) and f(0)(980) resonances. Our results are consistent with the present upper bound for a(0)(980) production and only a factor three smaller, indicating that future runs with more statistics should find actual numbers for this reaction from where we can learn more about the origin of the scalar resonances and their nature.
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Molina, R., Doring, M., Liang, W. H., & Oset, E. (2021). The pi f(0)(500) decay of the a(1)(1260). Eur. Phys. J. C, 81(9), 782–9pp.
Abstract: We evaluate the a(1)(1260) -> pi sigma(f(0)(500)) decay width from the perspective that the a(1)(1260) resonance is dynamically generated from the pseudoscalar-vector interaction and the sigma arises from the pseudoscalar-pseudoscalar interaction. A triangle mechanism with a(1)(1260) -> p pi followed by rho -> pi pi and a fusion of two pions within the loop to produce the sigma provides the mechanism for this decay under these assumptions for the nature of the two resonances. We obtain widths of the order of 13-22 MeV. Present experimental results differ substantially from each other, suggesting that extra efforts should be devoted to the precise extraction of this important partial decay width, which should provide valuable information on the nature of the axial vector and scalar meson resonances and help clarify the role of the ps channel in recent lattice QCD calculations of the a(1).
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