Garzon, E. J., & Xie, J. J. (2015). Effects of a Nc(c)over-bar* resonance with hidden charm in the pi(-)p -> D-Sigma(+)(c) reaction near threshold. Phys. Rev. C, 92(3), 035201–4pp.
Abstract: We study the effect of a hidden charm nuclear excited state N-c (c) over bar* in the pi(-)p -> D-Sigma(+)(c) reaction near threshold using an effective Lagrangian approach. We calculate the background contribution of the t and u channels by the D*(0) vector meson exchange and Sigma(++)(c) intermediate state, respectively. We show that the consideration of a N-c (c) over bar* resonance provides an enhancement of the total cross section close to the reaction threshold. We also evaluate the differential cross section for different energies and we study the angle dependence. It is expected that our model calculations will be tested in future experiments.
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Xie, J. J., Oset, E., & Geng, L. S. (2016). Photoproduction of the f(2)'(1525), a(2)(1320), and K-2(*) (1430). Phys. Rev. C, 93(2), 025202–8pp.
Abstract: Assuming that the f(2)'(1525), a(2)(1320), and K-2(*) (1430) resonances are dynamically generated states from vector-meson-vector-meson interactions in the s-wave with spin S = 2, we study the gamma p -> f(2)'(1525)p, gamma p -> a(2)(0)(1320)p, and gamma p -> K-2(*)(1430)Lambda(Sigma) reactions. These reactions proceed in the following way: the incoming photon first mutates into a rho(0), omega, or phi meson via vector-meson dominance, which then interacts with the rho(0), omega, or K* emitted by the incoming proton to form the tensor mesons f(2)(')(1525), a(2)(1320), and K-2(*)(1430). The picture is simple and has no free parameters, as all the parameters of the mechanism have been fixed in previous studies. We predict the differential and total cross sections of these reactions. The results can be tested in future experiments and therefore offer new clues about the nature of these tensor states.
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Xie, J. J., Liang, W. H., & Oset, E. (2016). (K)over-bar-induced formation of the f(0)(980) and a(0)(980) resonances on proton targets. Phys. Rev. C, 93(3), 035206–8pp.
Abstract: We perform a calculation of the cross section for nine reactions induced by (K) over bar scattering on protons. The reactions studied are K- p -> Lambda pi(+)pi(-), K- p -> Sigma(0)pi(+)pi(-), K- p -> Lambda pi(0)eta, K- p -> Sigma(0)pi(0)eta, K- p -> Sigma(+)pi(-)eta, (K) over bar (0) p -> Lambda pi(+)eta, (K) over bar (0) p -> Sigma(0)pi(+)eta, (K) over bar (0) p -> Sigma(+)pi(+)pi(-), and (K) over bar (0) p -> Sigma+pi(0)eta. We find that in the reactions producing pi(+)pi(-), a clear peak for the f(0)(980) resonance is found, while no trace of f(0)(500) appears. Similarly, in the cases of p. production, a strong peak is found for the a(0)(980) resonance, with the characteristic strong cusp shape. Cross sections and invariant mass distributions are evaluated which should serve, by comparing them with future data, to test the dynamics of the chiral unitary approach used for the evaluations and the nature of these resonances.
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Chen, H. X., Geng, L. S., Liang, W. H., Oset, E., Wang, E., & Xie, J. J. (2016). Looking for a hidden-charm pentaquark state with strangeness S =-1 from Xi(-)(b) decay into J/Psi K- Lambda. Phys. Rev. C, 93(6), 065203–9pp.
Abstract: Assuming that the recently observed hidden-charm pentaquark state, P-c(4450), is of molecular nature as predicted in the unitary approach, we propose to study the decay of Xi(-)(b) -> J/psi K-Lambda to search for the strangeness counterpart of the P-c(4450). There are three ingredients in the decay mechanism: the weak decay mechanism, the hadronization mechanism, and the final state interactions in the meson-baryon system of strangeness S = -2 and isospin I = 1/2 and of the J/psi Lambda. All these have been tested extensively. As a result, we provide a genuine prediction of the invariant mass distributions where a strangeness hidden-charm pentaquark state, the counterpart of the P-c(4450), can be clearly seen. The decay rate is estimated to be of similarmagnitude as the Lambda(0)(b) -> J/psi K(-)p measured by the LHCb Collaboration.
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Wang, E., Xie, J. J., Liang, W. H., Guo, F. K., & Oset, E. (2017). Role of a triangle singularity in the gamma p -> K+Lambda (1405) reaction. Phys. Rev. C, 95(1), 015205–9pp.
Abstract: We show the effects of a triangle singularity mechanism for the gamma p -> K+Lambda(1405) reaction. The mechanism has a N-* resonance around 2030 MeV, which decays into K*Sigma. The K-* decays to K+ pi, and the pi Sigma merge to form the Lambda (1405). This mechanism produces a peak around root s = 2110 MeV, and has its largest contribution around cos theta= 0. The addition of this mechanism to other conventional ones leads to a good reproduction of d sigma/dcos theta and the integrated cross section around this energy, providing a solution to a problem encountered in previous theoretical models.
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Xie, J. J., Liang, W. H., Oset, E., Moskal, P., Skurzok, M., & Wilkin, C. (2017). Determination of the eta He-3 threshold structure from the low energy pd -> eta He-3 reaction. Phys. Rev. C, 95(1), 015202–9pp.
Abstract: We analyze the data on cross sections and asymmetries for the pd -> eta He-3 reaction close to threshold and look for bound states of the eta He-3 system. Rather than parameterizing the scattering matrix, as is usually done, we develop a framework in which the eta He-3 optical potential is the key ingredient, and its strength, 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 eta He-3 loop function incorporates the range of the interaction given by the empirical He-3 density. We find a local Breit-Wigner form of the eta He-3 amplitude T below threshold with a clear peak in vertical bar T vertical bar(2), which corresponds to an eta He-3 binding of about 0.3 MeV and a width of about 3 MeV. By fitting the potential we can also evaluate the eta He-3 scattering length, including its sign, thus resolving the ambiguity in the former analyses.
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Oset, E., Chen, H. X., Feijoo, A., Geng, L. S., Liang, W. H., Li, D. M., et al. (2016). Study of reactions disclosing hidden charm pentaquarks with or without strangeness. Nucl. Phys. A, 954, 371–392.
Abstract: We present results for five reactions, Lambda(b) -> J/psi K(-)p, Lambda(b) -> J/psi eta Lambda, Lambda(b) -> J/psi pi(-)p, Lambda(b) -> J/psi K-0 Lambda and Xi(-)(b) -> J/psi K-Lambda, where combining information from the meson baryon interaction, using the chiral unitary approach, and predictions made for molecular states of hidden charm, with or without strangeness, we can evaluate invariant mass distributions for the light meson baryon states, and for those of J/psi p or J/psi Lambda. We show that with the present available information, in all of these reactions one finds peaks where the pentaquark states show up. In the Lambda(b) -> J/psi K(-)p, and Lambda(b) -> J/psi pi(-)p reactions we show that the results obtained from our study are compatible with present experimental observations.
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Oset, E., Albaladejo, M., Xie, J. J., & Ramos, A. (2014). Recent developments on hadron interaction and dynamically generated resonances. Int. J. Mod. Phys. E, 23(7), 1461008–8pp.
Abstract: In this talk I report on the recent developments in the subject of dynamically generated resonances. In particular I discuss the gamma p -> K-0 Sigma+ and gamma n -> K-0 Sigma(0) reactions, with a peculiar behavior around the K*(0)Lambda threshold, due to a 1/2(-) resonance around 2035 MeV. Similarly, I discuss a BES experiment, J/psi -> eta K*(0) (K) over bar*(0) decay, which provides evidence for a new h(1) resonance around 1830 MeV that was predicted from the vector-vector interaction. A short discussion is then made about recent advances in the charm and beauty sectors.
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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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