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Dai, L. R., & Oset, E. (2024). Dynamical generation of the scalar f0(500), f0(980), and K0*(700) resonances in the Ds+ → K+ π+ π- reaction. Phys. Rev. D, 109(5), 054008–9pp.
Abstract: We develop a model aimed at understanding the three mass distributions of pairs of mesons in the Cabibbo-suppressed D-s(+) – K+pi(+)pi(-) decay recently measured with high statistics by the BESIII collaboration. The largest contributions to the process come from the D-s(+) -> K+ rho(0) and D-s(+) -> K*(0)pi(+) decay modes, but the D-s(+) -> K-0*(1430)pi(+) and D-s(+) -> K+ f(0) (1370) modes also play a moderate role and all of them are introduced empirically. Instead, the contribution of the f(0)(500), f(0)(980) , and K-0*(700) resonances is introduced dynamically by looking at the decay modes at the quark level, hadronizing q (q) over bar over bar pairs to give two mesons, and allowing these mesons to interact, for which we follow the chiral unitary approach, to finally produce the K+ pi(+) pi(-) final state. While the general features of the mass distributions are fairly obtained, we pay special attention to the specific effects created by the light scalar resonances, which are visible in the low mass region of the pi(+) pi(-) (f(0)(500) and K+ pi(-) K+pi-(K-0*(700)) mass distributions and a narrow peak for pi(+) pi(-) distribution corresponding to f(0)(980) excitation. The contribution of these three resonances is generated by only one parameter. We see the agreement found in these regions as further support for the nature of the light scalar states as dynamically generated from the interaction of pseudoscalar mesons.
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Dai, L. R., & Oset, E. (2020). Helicity amplitudes in the (B)over-bar -> D*(nu)over-bar(tau)tau decay with V-A breaking in the quark sector. Eur. Phys. J. A, 56(5), 154–8pp.
Abstract: In view of the recent measurement of the F-D*(L) magnitude in the (B) over bar -> D*(nu) over bar (tau)tau reaction we evaluate this magnitude within the standard model and for a family of models with the gamma(mu) – alpha gamma(mu)gamma(5) current structure for the quarks for different values of a. At the same time we evaluate also the transverse contributions, M = -1, M = +1, and find that the difference between the M = -1 and M = +1 contributions is far more sensitive to changes in a than the longitudinal component. These findings should be looked as an incentive to measure the transverse helicities which are bound to be a far more sensitive magnitude to possible new physics than F-D*(L).
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Dai, L. R., & Oset, E. (2018). Polarization amplitudes in VP decay beyond the Standard Model. Eur. Phys. J. A, 54(12), 219–10pp.
Abstract: We study the amplitudes of the -VP decay for the different polarizations of the vector meson V, using a formalism where the mapping from the quark degrees of freedom to the meson ones is done with the P-3(0) model. We extend the formalism to a case, with the operator -5, that can account for different models beyond the Standard Model and study in detail the -K*0K- reaction for the different polarizations of the K*0. The results are shown in terms of the parameter that differs for each model. We find that is very different for each of the third components of the vector spin, M=+/- 1,0, and in particular the magnitude |M=-1 is very sensitive to the parameter, which makes the investigation of this magnitude very useful to test different models beyond the Standard Model.
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Dai, L. R., & Oset, E. (2018). Helicity amplitudes in B -> D*(nu)over-barl decay. Eur. Phys. J. C, 78(11), 951–11pp.
Abstract: We use a recent formalism of the weak hadronic reactions that maps the transition matrix elements at the quark level into hadronic matrix elements, evaluated with an elaborate angular momentum algebra that allows finally to write the weak matrix elements in terms of easy analytical formulas. In particular they appear explicitly for the different spin third components of the vector mesons involved. We extend the formalism to a general case, with the operator parameter, which suggest to use this magnitude to test different models beyond the standard model. We show that our formalism implies the heavy quark limit and compare our results with calculations that include higher order corrections in heavy quark effective theory. We find very similar results for both approaches in normalized distributions, which are practically identical at the end point of M-inv((nu l)) = m(B) – m(D)*
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Dai, L. R., & Oset, E. (2013). Tests on the molecular structure of f(2)(1270), f'(2) (1525) from psi(nS) and Upsilon(nS) decays. Eur. Phys. J. A, 49(10), 130–6pp.
Abstract: Based on previous studies that support the vector-vector molecular structure of the f(2)'(1270), f 2 (1525), K * 0 2 (1430), f0(1370) and f0(1710) resonances, we make predictions for the.(2S) decay into.(f) f2(1270),.(f) f 2 (1525), K* 0 (892) K * 0 2 (1430) and the radiative decay of.(1S),.(2S),.(2S) into.f2(1270),.f 2 (1525),.f0(1370),.f0(1710). Agreement with experimental data is found for three available ratios, without using free parameters, and predictions are done for other cases.
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