Feijoo, A., Wang, W. F., Xiao, C. W., Wu, J. J., Oset, E., Nieves, J., et al. (2023). A new look at the P-cs states from a molecular perspective. Phys. Lett. B, 839, 137760–7pp.
Abstract: We have a look at the P-cs states generated from the interaction of (D) over bar(*)Xi(c)('*) coupled channels. We consider the blocks of pseudoscalar-baryon (1/2(+) , 3/2(+)) and vector-baryon (1/2(+), 3/2(+)), and find 10 resonant states coupling mostly to (D) over bar Xi(c), <(D)*over bar>*Xi(c), (D) over bar Xi(c)' <(DA novel aspect of the work is the realization that the <(Dover bar>Xi(c), (Dover bar>(s) Lambda(c) or (Dover bar>*Xi(c), D-s*Lambda(c) channels, with a strong transition potential, collaborate to produce a larger attraction than the corresponding states <(Dover bar>Xi(c), <(Dover bar>Lambda(c) or (D) over bar*Xi(c), (D) over bar*Lambda(c) appearing in the generation of the strangenessless P-c states, since in the latter case the transition potential between those channels is zero. The extra attraction obtained in the (D) over bar Xi(c), (D) over bar* Xi(c) pairs preclude the association of the P-cs(4338) state coupling mostly to (D) over bar*Xi(c) while the P-cs(4459) is associated to the state found that couples mostly to (D) over bar Xi(c)'. Four more states appear, like in other molecular pictures, and some of the states are degenerate in spin. Counting different spin states we find 10states, which we hope can be observed in the near future.
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Molina, R., Xiao, C. W., Liang, W. H., & Oset, E. (2024). Correlation functions for the N*(1535) and the inverse problem. Phys. Rev. D, 109(5), 054002–10pp.
Abstract: The N*(1535) can be dynamically generated in the chiral unitary approach with the coupled channels, K0E+; K+E0; K+A, and eta p. In this work, we evaluate the correlation functions for every channel and face the inverse problem. Assuming the correlation functions to correspond to real measurements, we conduct a fit to the data within a general framework in order to extract the information contained in these correlation functions. The bootstrap method is used to determine the uncertainties of the different observables, and we find that, assuming errors of the same order than in present measurements of correlation functions, one can determine the scattering length and effective range of all channels with a very good accuracy. Most remarkable is the fact that the method predicts the existence of a bound state of isospin 12 nature around the mass of the N*(1535) with an accuracy of 6 MeV. These results should encourage the actual measurement of these correlation functions (only the K+A one is measured so far), which can shed valuable light on the relationship of the N*(1535) state to these coupled channels, a subject of continuous debate.
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Li, H. P., Yi, J. Y., Xiao, C. W., Yao, D. L., Liang, W. H., & Oset, E. (2024). Correlation function and the inverse problem in the BD interaction. Chin. Phys. C, 48(5), 053107–7pp.
Abstract: We study the correlation functions of the (BD+)-D-0, (B+D0) system, which develops a bound state of approximately 40MeV, using inputs consistent with the T-cc(3875) state. Then, we address the inverse problem starting from these correlation functions to determine the scattering observables related to the system, including the existence of the bound state and its molecular nature. The important output of the approach is the uncertainty with which these observables can be obtained, considering errors in the (BD+)-D-0, (B+D0) correlation functions typical of current values in correlation functions. We find that it is possible to obtain scattering lengths and effective ranges with relatively high precision and the existence of a bound state. Although the pole position is obtained with errors of the order of 50% of the binding energy, the molecular probability of the state is obtained with a very small error of the order of 6%. All these findings serve as motivation to perform such measurements in future runs of high energy hadron collisions.
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Lin, J. X., Chen, H. X., Liang, W. H., Xiao, C. W., & Oset, E. (2024). (B)over-bars0 → Ds1(2460)+ K-, Ds1(2536)+ K- and the nature of the two Ds1 resonances. Eur. Phys. J. C, 84(4), 439–8pp.
Abstract: Starting from the molecular picture for the D-s1(2460) and D-s1(2536) resonances, which are dynamically generated by the interaction of coupled channels, the most important of which are the D* K for the D-s1(2460) and DK* for the D-s1(2536), we evaluate the ratio of decay widths for the (B) over bar (0)(s) -> D-s1(2460)(+) K- and (B) over bar (0)(s) -> D-s1(2536)(+) K- decays, the latter of which has been recently investigated by the LHCb collaboration, and we obtain a ratio of the order of unity. The present results should provide an incentive for the related decay into the D-s1(2460) resonance to be performed, which would provide valuable information on the nature of these two resonances.
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Xiao, C. W., Dias, J. M., Dai, L. R., Liang, W. H., & Oset, E. (2024). Triangle singularity in the J/ψ → ϕ π+ a−0(π−η) ,ϕ π− a+0(π+η) decays. Phys. Rev. D, 109(7), 074033–11pp.
Abstract: We study the J= psi -> phi pi + a 0 ( 980 ) – ( a – 0 -> pi – eta ) decay, evaluating the double mass distribution in terms of the pi – eta and pi + a – 0 invariant masses. We show that the pi – eta mass distribution exhibits the typical cusp structure of the a 0 ( 980 ) seen in recent high statistics experiments, and the pi + a – 0 spectrum shows clearly a peak around M inv ( pi + a – 0 ) = 1420 MeV, corresponding to a triangle singularity. When integrating over the two invariant masses we find a branching ratio for this decay of the order of 10 – 5 , which is easily accessible in present laboratories. We also call attention to the fact that the signal obtained is compatible with a bump experimentally observed in the eta pi + pi – mass distribution in the J= psi -> phi eta pi + pi – decay and encourage further analysis to extract from there the phi pi + a – 0 and phi pi – a + 0 decay modes.
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Molina, R., Liang, W. H., Xiao, C. W., Sun, Z. F., & Oset, E. (2024). Two states for the Ξ(1820) resonance. Phys. Lett. B, 856, 138872–4pp.
Abstract: We recall that the chiral unitary approach for the interaction of pseudoscalar mesons with the baryons of the decuplet predicts two states for the Xi(1820) resonance, one with a narrow width and the other one with a large width. We contrast this fact with the recent BESIII measurement of the K- Lambda mass distribution in the psi(3686) decay to K- Lambda Xi(+), which demands a width much larger than the average of the PDG, and show how the consideration of the two Xi(1820) states provides a natural explanation to the experimental data.
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Song, J., Liang, W. H., Xiao, C. W., Dias, J. M., & Oset, E. (2024). Testing the molecular nature of the Ω (2012) with the ψ (3770) → (Ω)over-bar(K)over-barΞ and ψ (3770) → (Ω)over-bar(K)over-barΞ* (1530) ((Ω)over-bar(K)over-barπΞ) reactions. Eur. Phys. J. C, 84(12), 1311–7pp.
Abstract: We report on the reactions psi(3770) -> (Omega) over bar+(K) over bar Xi and psi(3770) -> (Omega) over bar (+)(K) over bar Xi*(1530) (Xi* (1530) -> pi Xi), and calculate the mass distributions d Gamma/dM(inv)((K) over bar Xi) and d Gamma/dM(inv)(K Xi*), respectively. We obtain clear peaks corresponding to the Omega(2012). From the decay of psi(3770) -> (Omega) over bar (+)(K) over bar Xi*, we also get a second, broader, peak around 2035MeV, which comes from the Omega(2012) decay to (K) over bar Xi*. This second peak is closely tied to the molecular picture of the Omega(2012) with the (K) over bar Xi* (1530) and eta Omega components. Its observation would provide a boost to the molecular picture of the Omega (2012).
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Lyu, W. T., Duan, M. Y., Xiao, C. W., Wang, E., & Oset, E. (2024). Possible signal of an exotic I=1, J=2 state in the B → D*- D+ K+ reaction. Eur. Phys. J. C, 84(12), 1302–6pp.
Abstract: We study the B+ -> D*(-) D+ K+ reaction, showing that a peak in the D+ K+ mass distribution around 2834 MeV reported by LHCb could be associated with a theoretical exotic state with that mass, a width of 19 MeV and J(P) = 2(+), stemming from the interaction of the D*K+*(+) and D-s*(+) rho(+) channels, which is a partner of the 0(+) T-c (s) over bar (2900). We show that the data is compatible with this assumption, but also see that the mass distribution itself cannot discriminate between the spins J = 0, 1, 2 of the state. Then we evaluate the momenta of the angular mass distribution and show that they are very different for each of the spin assumptions, and that the momenta coming from interference terms have larger strength at the resonant energy than the peaks seen in the angular integrated mass distribution. We make a call for the experimental determination of these magnitudes, which has already been used by the LHCb in related decay reactions.
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Li, H. P., Xiao, C. W., Liang, W. H., Wu, J. J., Wang, E., & Oset, E. (2024). How to unravel the nature of the Σ*(1430)(1/2-) state from correlation functions. Phys. Rev. D, 110(11), 114018–12pp.
Abstract: We calculate the correlation functions for the K <overline> 0 p ; c+E0;c0E+;c+A, and riE+ states, which in the chiral unitary approach predict an excited E*(1/2-) state at the Collaboration. Once this is done, we tackle the inverse problem of seeing how much information one can obtain from these correlation functions. With the resampling method, one can determine the scattering parameters of all the channels with relative precision, by means of the analysis in a general framework, and find a clear cusplike structure corresponding to the E*(1/2-) in the different amplitudes at the K <overline> N threshold. KN threshold, recently observed by the Belle
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Duan, M. Y., Lyu, W. T., Xiao, C. W., Wang, E., Xie, J. J., Chen, D. Y., et al. (2025). Λc+ → ηπ+ Λ reaction and the Λa0+(980) and π+Λ(1670) contributions. Phys. Rev. D, 111(1), 016004–10pp.
Abstract: We study from the theoretical point of view the Lambda(+)(c) ->pi(+) eta Lambda reaction, recently measured by the Belle and BESIII Collaborations, where clear signals are observed for a(0)(980), Lambda(1670), and Sigma(1385) excitation. By considering the a(0)(980) and Lambda(1670) as dynamically generated resonances from the meson meson and meson baryon interaction, respectively, we are able to determine their relative production strengths in the reaction, which is also tied to the strength of the pi(+) eta Lambda tree level contribution. We observe that this latter strength is very big and there are large destructive interferences between the tree level and the rescattering terms where the a(0)(980) and Lambda(1670) are generated. The Sigma(1385) contribution is included by means of a free parameter, the only one of the theory, up to a global normalization, when one considers only external emission, and we observe that the spin flip part of this term, usually ignored in theoretical and experimental works, plays an important role determining the shape of the mass distributions. Internal emission is also considered and it is found to a minor role.
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