Oset, E., Bayar, M., Dote, A., Hyodo, T., Khemchandani, K. P., Liang, W. H., et al. (2016). Two-, Three-, Many-body Systems Involving Mesons. Multimeson Condensates. Acta Phys. Pol. B, 47(2), 357–365.
Abstract: In this paper, we review results from studies with unconventional many-hadron systems containing mesons: systems with two mesons and one baryon, three mesons, some novel systems with two baryons and one meson, and finally, systems with many vector mesons, up to six, with their spins aligned forming states of increasing spin. We show that in many cases, one has experimental counterparts for the states found, while in some other cases, they remain as predictions, which we suggest to be searched in BESIII, Belle, LHCb, FAIR and other facilities.
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Geng, L. S., Molina, R., & Oset, E. (2017). On the chiral covariant approach to rho rho scattering. Chin. Phys. C, 41(12), 124101–9pp.
Abstract: We examine in detail a recent work (D. Gulmez, U. G. Meibner and J. A. Oller, Eur. Phys. J. C, 77: 460 (2017)), where improvements to make rho rho scattering relativistically covariant are made. The paper has the remarkable conclusion that the J=2 state disappears with a potential which is much more attractive than for J=0, where a bound state is found. We trace this abnormal conclusion to the fact that an “on-shell” factorization of the potential is done in a region where this potential is singular and develops a large discontinuous and unphysical imaginary part. A method is developed, evaluating the loops with full rho propagators, and we show that they do not develop singularities and do not have an imaginary part below threshold. With this result for the loops we define an effective potential, which when used with the Bethe-Salpeter equation provides a state with J=2 around the energy of the f(2)(1270). In addition, the coupling of the state to is evaluated and we find that this coupling and the T matrix around the energy of the bound state are remarkably similar to those obtained with a drastic approximation used previously, in which the q(2) terms of the propagators of the exchanged rho mesons are dropped, once the cut-off in the rho rho loop function is tuned to reproduce the bound state at the same energy.
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Dias, J. M., Debastiani, V. R., Xie, J. J., & Oset, E. (2018). The radiative decay D-0 -> (K)over-bar*(0)gamma with vector meson dominance. Chin. Phys. C, 42(4), 043106–7pp.
Abstract: Motivated by the experimental measurements of D-0 radiative decay modes, we have proposed a model to study the D-0 -> (K) over bar*(0)gamma decay, by establishing a link with D-0 -> (K) over bar*(0) V (V = rho(0), omega) decays through the vector meson dominance hypothesis. In order to do this properly, we have used the Lagrangians from the local hidden gauge symmetry approach to account for V gamma conversion. As a result, we have found the branching ratio B[D-0 -> (K) over bar*(0)gamma]=(1.55-3.44)x10(-4), which is in fair agreement with the experimental values reported by the Belle and BaBar collaborations.
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Liang, W. H., Sakai, S., Xie, J. J., & Oset, E. (2018). Triangle singularity enhancing isospin violation in (B)over-bar(s)(0)-> J/psi pi(0)f(0)(980). Chin. Phys. C, 42(4), 044101–9pp.
Abstract: We perform calculations for the (B) over bar (0)(s)-> J/psi pi(0)f(0)(980) and (B) over bar (0)(s)-> J/psi pi(0)a(0)(980) reactions, showing that the first is isospin-suppressed while the second is isospin-allowed. The reaction proceeds via a triangle mechanism, with (B) over bar (0)(s)-> J/psi K*(K) over bar +c.c., followed by the decay K*-> K pi and a further fusion of K (K) over bar into the f(0)(980) or a(0)(980). We show that the mechanism develops a singularity around the pi(0)f(0)(980) or pi(0)a(0)(980) invariant mass of 1420 MeV, where the pi(0)f(0) and pi(0)a(0) decay modes are magnified and also the ratio of pi(0)f(0) to pi(0)a(0) production. Using experimental information for the (B) over bar (0)(s)-> J/psi K*(K) over bar +c.c. decay, we are able to obtain absolute values for the reactions studied which fall into the experimentally accessible range. The reactions proposed and the observables evaluated, when contrasted with actual experiments, should be very valuable to obtain information on the nature of the low lying scalar mesons.
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Wang, E., Xie, J. J., Geng, L. S., & Oset, E. (2019). The X(4140) and X(4160) resonances in the e(+)e(-) -> gamma J/psi phi reaction. Chin. Phys. C, 43(11), 113101–10pp.
Abstract: We investigate the J/psi phi invariant mass distribution in the e(+)e(-) -> gamma J/psi phi reaction at a center-of-mass energy of root s = 4.6 GeV measured by the BESIII collaboration, which concluded that no significant signals were observed for e(+)e(-) -> gamma J/psi phi because of the low statistics. We show, however, that the J/psi phi invariant mass distribution is compatible with the existence of the X(4140) state, appearing as a peak, and a strong cusp structure at the D-s*(D) over bar (s)* threshold, resulting from the molecular nature of the X(4160) state, which provides a substantial contribution to the reaction. This is consistent with our previous analysis of the B+ -> J psi phi K+ decay measured by the LHCb collaboration. We strongly suggest further measurements of this process with more statistics to clarify the nature of the X(4140) and X(4160) resonances.
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Dias, J. M., Yu, Q. X., Liang, W. H., Sun, Z. F., Xie, J. J., & Oset, E. (2020). Xi(bb) and Omega(bbb) molecular states. Chin. Phys. C, 44(6), 064101–8pp.
Abstract: Using the vector exchange interaction in the local hidden gauge approach, which in the light quark sector generates the chiral Lagrangians and has produced realistic results for Omega(C), Xi(c), Xi(b) and the hidden charm pentaquark states, we study the meson-baryon interactions in the coupled channels that lead to the Xi(bb) and Omega(bbb) excited states of the molecular type. We obtain seven states of the Xi(bb) type with energies between and MeV, and one Omega(bbb) state at MeV.
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Li, J. T., Lin, J. X., Zhang, G. J., Liang, W. H., & Oset, E. (2022). The (B)over-bar(s)(0) -> J/psi pi(0)eta decay and the a(0)(980)- f(0)(980) mixing. Chin. Phys. C, 46(8), 083108–6pp.
Abstract: We study the (B) over bar (0)(s) -> J/psi f(0)(980) and (B) over bar (0)(s) -> J/psi a(0)(980) reactions, and pay attention to the different sources of isospin violation and mixing of f(0)(980) and a(0)(980) resonances where these resonances are dynamically generated from meson-meson interactions. We fmd that the main cause of isospin violation is isospin breaking in the meson-meson transition T matrices, and the other source is that the loops involving kaons in the production mechanism do not cancel due to the different masses of charged and neutral kaons. We obtain a branching ratio for a(0)(980) production of the order of 5 x 10(-6) . Future experiments can address this problem, and the production rate and shape of the pi(0)eta mass distribution will definitely help to better understand the nature of scalar resonances.
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Molina, R., Ikeno, N., & Oset, E. (2023). Sequential single pion production explaining the dibaryon “d*(2380)” peak. Chin. Phys. C, 47(4), 041001–10pp.
Abstract: In this study, we investigate the two step sequential one pion production mechanism, that is, np(I=0)->pi(-)pp followed by the fusion reaction pp ->pi(+)d, to describe the np ->pi(+)pi(-)d reaction with in state I = 0 . In this reaction, a narrow peak identified with a “ d(2380) ” dibaryon has been previously observed. We discover that the second reaction step pp ->pi(+)d is driven by a triangle singularity that determines the position of the peak of the reaction and the high strength of the cross section. The combined cross section of these two mechanisms produces a narrow peak with a position, width, and strength, that are compatible with experimental observations within the applied approximations made. This novel interpretation of the peak accomplished without invoking a dibaryon explains why this peak has remained undetected in other reactions.
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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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Jido, D., Oset, E., & Sekihara, T. (2011). Kaon-induced Lambda(1405) production on a deuteron target at DAFNE. Eur. Phys. J. A, 47(3), 42–7pp.
Abstract: The K-- induced production of.(1405) in the K(-)d -> pi Sigma n reaction is investigated having in mind the conditions of the DAFNE facility at Frascati where kaons are obtained from the decay of slow-moving phi mesons. We find that the K(-)d -> Lambda(1405)n process favors the production of Lambda(1405) initiated by the K(-)p channel, which gives largest weight to the higher mass Lambda(1405) appearing at 1420MeV in chiral theories. We find that the fastest kaons from the decay of the phi are well suited to see this resonance, particularly if one selects forward going neutrons in the center of mass, which reduce the contribution of single scattering and make the double scattering dominate where the signal of the resonance appears clearer.
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