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Liang, W. H., Molina, R., Xie, J. J., Doring, M., & Oset, E. (2015). Predictions for the X(YZ) and X(YZ) with X(4160), Y(3940), Z(3930). Eur. Phys. J. A, 51(5), 58–7pp.
Abstract: We investigate the decay of and with R being the , , resonances. Under the assumption that these states are dynamically generated from the vector-vector interaction, as has been concluded from several theoretical studies, we use a reaction mechanism of quark production at the elementary level, followed by hadronization of one final pair into two vectors and posterior final state interaction of this pair of vector mesons to produce the resonances. With this procedure we are able to predict five ratios for these decays, which are closely linked to the dynamical nature of these states, and also predict the order of magnitude of the branching ratios which we find of the order of , well within the present measurable range. In order to further test the dynamical nature of these resonances we study the and decays close to the and thresholds and make predictions for the ratio of the mass distributions in these decays and the decay widths. The measurement of these decays rates can help unravel the nature of these resonances.
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Xie, J. J., & Oset, E. (2015). Photoproduction of the f(2)(1270) resonance. Eur. Phys. J. A, 51(9), 111–7pp.
Abstract: We have performed a calculation of the gamma(p) -> pi(+) p-p reaction, where the two pions have been separated in D-wave producing the f(2)(1270) resonance. We use elements of the local hidden gauge approach that provides the interaction of vector mesons in which the f(2)(1270) resonance appears as rho-rho. molecular state in L = 0 and spin 2. The vector meson dominance, incorporated in the local hidden gauge approach converts a photon into a rho(0) meson and the other meson connects the photon with the proton. The picture is simple and has no free parameters, since the parameters of the theory have been constrained in the previous study of the vector-vector states. In a second step we introduce new elements, not present in the local hidden gauge approach, adapting the rho propagator to Regge phenomenology and introducing the rho NN tensor coupling. We find that both the differential cross section as well as the t dependence of the cross section are in good agreement with the experimental results and provide support for the molecular picture of the f(2)(1270) resonance in the first baryonic reaction where it has been tested.
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Xie, J. J., Liang, W. H., & Oset, E. (2019). eta-He-4 interaction from the dd->eta He-4 reaction near threshold. Eur. Phys. J. A, 55(1), 6–8pp.
Abstract: .We analyze the data on the total cross sections for the dd4 He reaction close to threshold and look for possible 4 He bound states. We develop a framework in which the 4 He optical potential is the key ingredient, rather than parameterizing the scattering matrix, as is usually done. The strength of this potential, together with some production parameters, are fitted to the available experimental data. The relationship of the scattering matrix to the optical potential is established using the Bethe-Salpeter equation and the 4 He loop function incorporates the range of the interaction given by the experimental He-4 density. However, when we look for poles of the scattering matrix, we get poles in the bound region, poles in the positive energy region or no poles at all. If we further restrict the results with constraints from a theoretical model with all its uncertainties the bound states are not allowed. However, we find a bump structure in |T|2 of the 4 He 4 He scattering amplitude below threshold for the remaining solutions.
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Liang, W. H., Xie, J. J., & Oset, E. (2015). (B)over-bar(0), B- and (B)over-bar(S)(0) decays into J/psi and K (K)over-bar or pi eta. Eur. Phys. J. C, 75(12), 609–8pp.
Abstract: We study the (B) over bar (0)(S) -> J/psi K+ K-, (B) over bar (0) -> J/psi K+ K, B- -> J/psi K+ K-, (B) over bar (0) -> J/psi pi(0)eta(-), decays and compare their mass distributions with those obtained for the (B) over bar (0)(S) -> J/psi pi(+) pi(-) and (B) over bar (0)(S) -> J/psi pi(+)pi(-). The approach followed consist in a factorization of the weak part and the hadronization part into a factor which is common to all the processes. Then what makes the reactions different are some trivial CabibboKobayashi- Maskawa matrix elements and the weight by which the different pairs of mesons appear in a primary step plus their final state interaction. These elements are part of the theory and thus, up to a global normalization factor, all the invariant mass distributions are predicted with no free parameters. Comparison is made with the limited experimental information available. Further comparison of these results with coming LHCb measurements will be very valuable to make progress in our understanding of the meson- meson interaction and the nature of the low lying scalar meson resonances, f(0)(500), f(0)( 980) and a(0)(980).
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Dai, L. R., Xie, J. J., & Oset, E. (2016). B-0 -> D-0 D-0 K-0, B+ -> D-0 D-0 K+, and the scalar DD bound state. Eur. Phys. J. C, 76(3), 121–9pp.
Abstract: We study the B-0 decay to D-0 D-0 K-0 based on the chiral unitary approach, which generates the X(3720) resonance, and we make predictions for the D D invariant mass distribution. From the shape of the distribution, the existence of the resonance below threshold could be induced. We also predict the rate of production of the X(3720) resonance to the D D mass distribution with no free parameters.
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