|
|
Pavao, R. P., Sakai, S., & Oset, E. (2017). Triangle singularities in B- -> D*(0)pi(-)pi(0)eta and B- -> D*(0)pi(-)pi(+)pi(-). Eur. Phys. J. C, 77(9), 599–8pp.
Abstract: The possible role of the triangle mechanism in the B- decay into D*(0)pi(-)pi(0)eta and D*(0)pi(-)pi(+)pi(-) is investigated. In this process, the triangle singularity appears from the decay of B- into D*K-0(-) K*(0) followed by the decay of K-*0 into pi(-) K+ and the fusion of the K+ K-, which forms the a(0)(980) or f(0)(980), which finally decay into pi(0)eta or pi(+)pi(-), respectively. The triangle mechanism from the (K) over bar * K (K) over bar loop generates a peak around 1420 MeV in the invariant mass of pi(-) a(0) or pi(-) f(0), and it gives sizable branching fractions, Br(B- -> D*(0)pi(-) a(0); a(0) -> pi(0)eta) = (1.66 +/- 0.45) x 10(-6) and Br(B- -> D*(0)pi(-) f(0); f(0) -> pi(+)pi(-)) = (2.82 +/- 0.75) x 10(-6).
|
|
|
|
Dai, L. R., Pavao, R., Sakai, S., & Oset, E. (2018). Anomalous enhancement of the isospin-violating Lambda(1405) production by a triangle singularity in Lambda(c) ->pi(+)pi(0)pi(0)Sigma(0). Phys. Rev. D, 97(11), 116004–10pp.
Abstract: The decay of Lambda(+)(c) into pi(+)pi(0) Lambda(1405) with the Lambda(1405) decay into pi(0)Sigma(0) through a triangle diagram is studied. This process is initiated by Lambda(+)(c) -> pi(+) (K) over bar N-*, and then the (K) over bar (*) decays into (K) over bar (pi) and (K) over bar N produce the Lambda(1405) through a triangle loop containing (K) over bar N-* (K) over bar which develops a singularity around 1890 MeV. This process is prohibited by the isospin symmetry, but the decay into this channel is enhanced by the contribution of the triangle diagram, which is sensitive to the mass of the internal particles. We find a narrow peak in the pi(0)Sigma(0) invariant mass distribution, which originates from the (K) over bar amplitude, but is tied to the mass differences between the charged and neutral (K) over bar or N states. The observation of the unavoidable peak of the triangle singularity in the isospin- violating Lambda(1405) production would provide further support for the hadronic molecular picture of the Lambda(1405) and further information on the (K) over bar N interaction.
|
|
|
|
Yu, Q. X., Pavao, R., Debastiani, V. R., & Oset, E. (2019). Description of the Xic and Xib states as molecular states. Eur. Phys. J. C, 79(2), 167–14pp.
Abstract: In this work we study several c and b states dynamically generated from the meson-baryon interaction in coupled channels, using an extension of the local hidden gauge approach in the Bethe-Salpeter equation. These molecular states appear as poles of the scattering amplitudes, and several of them can be identified with the experimentally observed c states, including the c(2790), c(2930), c(2970), c(3055) and c(3080). Also, for the recently reported b(6227) state, we find two poles with masses and widths remarkably close to the experimental data, for both the JP=1/2- and JP=3/2- sectors.
|
|
|
|
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.
|
|
