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Feijoo, A., Valcarce Cadenas, V., & Magas, V. K. (2023). The Xi(1620) and Xi(1690) molecular states from S =-2 meson-baryon interaction up to next-to-leading order. Phys. Lett. B, 841, 137927–6pp.
Abstract: We have studied the meson-baryon interaction in the neutral S = -2 sector using an extended Unitarized Chiral Perturbation Theory, which takes into account not only the leading Weinberg-Tomozawa term (as all the previous studies in S = -2 sector), but also the Born terms and next-to-leading order contribution. Based on the SU(3) symmetry of the chiral Lagrangian we took most of the model parameters from the BCN model [1], where these were fitted to a large amount of experimental data in the neutral S = -1 sector. We have shown that our approach is able to generate dynamically both Xi(1620) and Xi(1690) states in very reasonable agreement with the data, and can naturally explain the puzzle with the decay branching ratios of Xi(1690). Our results clearly illustrate the reliability of chiral models implementing unitarization in coupled channels and the importance of considering Born and NLO contributions for precise calculations.
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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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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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Song, J., Feijoo, A., & Oset, E. (2022). Role of meson interactions in the D-s(+) -> pi(+) pi(+) pi(-) eta decay. Phys. Rev. D, 106(7), 074027–20pp.
Abstract: We perform a theoretical study of the D-s(+) ->pi(+)pi(+)pi(-)eta decay. We look first at the basic D-s(+) decay at the quark level from external and internal emission. Then we hadronize a pair or two pairs of q (q) over bar states to have mesons at the end. Posteriorly the pairs of mesons are allowed to undergo final state interaction, by means of which the a(0)(980), f(0)(980), a(1)(1260), and b(1)(1235) resonances are dynamically generated. The G parity is used as a filter of the possible channels, and from those with negative G parity only the ones that can lead to pi(+)pi(+)pi(-)eta at the final state are kept. Using transition amplitudes from the chiral unitary approach that generates these resonances and a few free parameters, we obtain a fair reproduction of the six mass distributions reported in the BESIII experiment.
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Vidaña, I., Feijoo, A., Albaladejo, M., Nieves, J., & Oset, E. (2023). Femtoscopic correlation function for the Tcc(3875)+ state. Phys. Lett. B, 846, 138201–9pp.
Abstract: We have conducted a study of the femtoscopic correlation functions for the D0D*+ and D+D*0 channels that build the Tcc state. We develop a formalism that allows us to factorize the scattering amplitudes outside the integrals in the formulas, and the integrals involve the range of the strong interaction explicitly. For a source of size of 1 fm, we find values for the correlation functions of the D0D*+ and D+D*0 channels at the origin around 30 and 2.5, respectively, and we see these observables converging to unity already for relative momenta of the order of 200 MeV. We conduct tests to see the relevance of the different contributions to the correlation function and find that it mostly provides information on the scattering length, but should the correlation functions be measured with the precision of the latest experiments, the effective range of the D0D*+ could also be obtained.
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Wang, W. F., Feijoo, A., Song, J., & Oset, E. (2022). Molecular Omega(ce), Omega(bb), and Omega(bc) states. Phys. Rev. D, 106(11), 116004–14pp.
Abstract: We study the interaction of meson-baryon coupled channels carrying quantum numbers of a Omega(ce), Omega(bb), and Omega(bc) presently under investigation by the LHCb Collaboration. The interaction is obtained from an extension of the local hidden gauge approach to the heavy quark sector that has proved to provide accurate results compared to experiment in the case of Omega(c), Xi(c) states and pentaquarks, P-c and P-cs. We obtain many bound states, with small decay widths within the space of the chosen coupled channels. The spin-parity of the states are J(P) = 1/2(-) for coupled channels of pseudoscalar-baryon (1/2(+)), J(P) = 3/2(-) for the case of pseudoscalar-baryon (3/2(+)), J(P) = 1/2(-), 3/2(-) for the case of vector-baryon (1/2(+)) and J(P) = 1/2(-), 3/2(-). 5/2(-) for the vector- baryon (3/2(+)) channels. We look for poles of the states and evaluate the couplings to the different channels. The couplings obtained for the open channels can serve as a guide to see in which reaction the obtained states are more likely to be observed.
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