|
|
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.
|
|
|
|
Dai, L. R., Pavao, R., Sakai, S., & Oset, E. (2019). tau(-) -> nu tau M1 M2, with M1, M2 pseudoscalar or vector mesons. Eur. Phys. J. A, 55(2), 20–22pp.
Abstract: .We perform a calculation of the -M1M2, with M1,M2 either pseudoscalar or vector mesons using the basic weak interaction and angular momentum algebra to relate the different processes. The formalism also leads to a different interpretation of the role played by G-parity in these decays. We also observe that, while PPp-wave production is compatible with chiral perturbation theory and experiment, VP and VVp-wave production is clearly incompatible with experiment and we develop the formalism also in this case, producing the VP or VV pairs in s-wave. We compare our results with experiment and other theoretical approaches for rates and invariant mass distributions and make predictions for unmeasured decays. We show the value of these reactions, particularly if the M1M2 mass distribution is measured, as a tool to learn about the meson-meson interaction and the nature of some resonances, coupling to two mesons, which are produced in such decays.
|
|
|
|
Xie, J. J., & Oset, E. (2019). Search for the Sigma* state in Lambda(+)(c) -> pi(+)pi(0)pi(-)Sigma(+) decay by triangle singularity. Phys. Lett. B, 792, 450–453.
Abstract: A Sigma* resonance with spin-parity J(P) = 1/2(-) and mass in the vicinity of the (K) over barN threshold has been predicted in the unitary chiral approach and inferred from the analysis of CLAS data on the gamma p -> K+pi(0)Sigma(0) reaction. In this work, based on the dominant Cabibbo favored weak decay mechanism, we perform a study of Lambda(+)(c) -> pi(+)pi(0)Sigma* with the possible Sigma* state decaying into pi(-)Sigma(+) through a triangle diagram. This process is initiated by Lambda(+)(c) -> pi(+)(K) over bar *N, then the (K) over bar* decays into (K) over bar pi and (K) over barN produce the Sigma* through a triangle loop containing (K) over bar *N (K) over bar which develops a triangle singularity. We show that the pi(-)Sigma(+) state is generated from final state interaction of (K) over barN in S-wave and isospin I = 1, and the Lambda(+)(c) -> pi(+)pi(0)pi(-)Sigma(+) decay can be used to study the possible Sigma* state around the (K) over barN threshold. The proposed decay mechanism can provide valuable information on the nature of the Sigma* resonance and can in principle be tested by facilities such as LHCb, BelleII and BESIII.
|
|
|
|
Sekihara, T., Oset, E., & Ramos, A. (2016). On the structure observed in the in-flight He-3(K-, Lambda p)n reaction at J-PARC. Prog. Theor. Exp. Phys., 2016(12), 123D03–27pp.
Abstract: A theoretical investigation is done to clarify the origin of the peak structure observed near the K-pp threshold in the in-flight He-3(K-, Lambda p)n reaction of the J-PARC E15 experiment, which could be a signal of the lightest kaonic nuclei, i.e., the (K) over bar NN (I = 1/2) state. For the investigation, we evaluate the Lambda p invariant mass spectrum assuming two possible scenarios to interpret the experimental peak. One assumes that the Lambda (1405) resonance is generated after the emission of an energetic neutron from the absorption of the initial K-, not forming a bound state with the remaining proton. This uncorrelated Lambda (1405)p system subsequently decays into the final Lambda p. The other scenario implies that, after the emission of the energetic neutron, a (K) over bar NN bound state is formed, decaying eventually into a Lambda p pair. Our results show that the experimental signal observed in the in-flight He-3(K-, Lambda p)n reaction at J-PARC is qualitatively well reproduced by the assumption that a (K) over bar NN bound state is generated in the reaction, definitely discarding the interpretation in terms of an uncorrelated Lambda (1405)p s tate.
|
|
|
|
Aceti, F., Bayar, M., Dias, J. M., & Oset, E. (2014). Prediction of a Z(c)(4000) state and relationship with the claimed Z(c)(4025). Eur. Phys. J. A, 50(6), 103–13pp.
Abstract: After discussing the OZI suppression of one light meson exchange in the interaction of with isospin I = 1 , we study the contribution of the two-pion exchange to the interaction and the exchange of heavy vectors, J/psi for diagonal transitions and D-* for transitions of to J/psi rho. We find these latter mechanisms to be weak, but enough to barely bind the system in J = 2 with a mass around 4000 MeV, while the effect of the two-pion exchange is a net attraction, though weaker than that from heavy-vector exchange. We discuss this state and try to relate it to the Z (c) (4025) state, above the threshold, claimed in an experiment at BES from an enhancement of the distribution close to threshold. Together with the results from a recent reanalysis of the BES experiment showing that it is compatible with a J = 2 state below threshold around 3990 MeV, we conclude that the BES experiment could show the existence of the state that we find in our approach.
|
|
|
|
Oset, E., Ramos, A., Garzon, E. J., Molina, R., Tolos, L., Xiao, C. W., et al. (2012). Interaction of vector mesons with baryons and nuclei. Int. J. Mod. Phys. E, 21(11), 1230011–18pp.
Abstract: After some short introductory remarks on particular issues on the vector mesons in nuclei, in this paper, we present a short review of recent developments concerning the interaction of vector mesons with baryons and with nuclei from a modern perspective using the local hidden gauge formalism for the interaction of vector mesons. We present results for the vector-baryon interaction and in particular for the resonances which appear as composite states, dynamically generated from the interaction of vector mesons with baryons, taking also the mixing of these states with pseudoscalars and baryons into account. We then venture into the charm sector, reporting on hidden charm baryon states around 4400 MeV, generated from the interaction of vector mesons and baryons with charm, which have a strong repercussion on the properties of the J/Psi N interaction. We also address the interaction of K* with nuclei and make suggestions to measure the predicted huge width in the medium by means of transparency ratio. The formalism is extended to study the phenomenon of J/psi suppression in nuclei via J/psi photo-production reactions.
|
|
|
|
Martinez Torres, A., Dai, L. R., Koren, C., Jido, D., & Oset, E. (2012). KD, eta Ds interaction in finite volume and the Ds*0(2317) resonance. Phys. Rev. D, 85(1), 014027–11pp.
Abstract: An SU(4) extrapolation of the chiral unitary theory in coupled channels done to study the scalar mesons in the charm sector is extended to produce results in finite volume. The theory in the infinite volume produces dynamically the D-s*0(2317) resonance by means of the coupled channels KD, eta D-s. Energy levels in the finite box are evaluated and, assuming that they would correspond to lattice results, the inverse problem of determining the bound states and phase shifts in the infinite volume from the lattice data is addressed. We observe that it is possible to obtain accurate KD phase shifts and the position of the D-s*0(2317) state, but it requires the explicit consideration of the two coupled channels in the analysis if one goes close to the eta D-s threshold. We also show that the finite volume spectra look rather different in case the D-s*0(2317) is a composite state of the two mesons, or if it corresponds to a non molecular state with a small overlap with the two meson system. We then show that a careful analysis of the finite volume data can shed some light on the nature of the D-s*0(2317) resonance as a KD molecule or otherwise.
|
|
|
|
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.
|
|
|
|
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.
|
|
|
|
Dai, L. R., Xie, J. J., & Oset, E. (2015). Study of the f(2)(1270), f '(2)(1525), and (K)over-bar(2)*(1430), f(0)(1370) and f(0)(1710) production from psi(nS) and Upsilon(nS) decays. Phys. Rev. D, 91(9), 094013–6pp.
Abstract: Based on previous studies that support the important role of the f(2)(1270), f'(2)(1525), and (K) over bar (2)*(1430) resonances in the J/psi[psi(2S)] -> phi(omega)VV decays, we make an analysis of the analogous decays of Upsilon(1S) and Upsilon(2S), taking into account recent experimental data. In addition, we study the J/psi and psi(2S) radiative decays and we also made predictions for the radiative decay of Upsilon(1S) and Upsilon(2S) into gamma f(2)(1270), gamma f(2)'(1525), gamma f(0)(1370) and gamma f(0)(1710) comparing with the recent results of a CLEO experiment. We can compare our results for ratios of decay rates with eight experimental ratios and find agreement in all but one case, where experimental problems are discussed.
|
|
