Gong-Jie Zhang | Searcharxiv

arXiv2023

The $\bar B_s^0 \to J/ψπ^0 η$ decay and the $a_0(980)-f_0(980)$ mixing

We study the $\bar B_s^0 \to J/ψf_0(980)$ and $\bar B_s^0 \to J/ψa_0(980)$ 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 interaction. We find that the main cause of isospin violation is the 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 the charged and neutral kaons. We obtain a branching ratio for $a_0(980)$ production of the order of $5 \times 10^{-6}$. Future experiments can address this problem, and the production rate and shape of the $π^0 η$ mass distribution will definitely help to better understand the nature of scalar resonances.

hep-ph↗

arXiv2023

Theoretical interpretation of the $Ξ(1620)$ and $Ξ(1690)$ resonances seen in $Ξ_c^+ \to Ξ^- π^+ π^+$ decay

We study the Belle reaction $Ξ_c^+ \to Ξ^- π^+ π^+$ looking at the mass distribution of $π^+ Ξ$, where clear signals for the $Ξ(1620)$ and $Ξ(1690)$ resonances are seen. These two resonances are generated dynamically from the interaction in coupled channels of $πΞ, \bar K Λ, \bar K Σ$ and $ηΞ$ within the chiral unitary approach. Yet, the weak decay process at the quark level, together with the hadronization to produce pairs of mesons, does not produce the $ππΞ$ final state. In order to produce this state one must make transitions from the $\bar K Λ, \bar K Σ$ and $ηΞ$ components to $πΞ$, and this interaction is what produces the resonances. So, the reaction offers a good test for the molecular picture of these resonances. Adding the contribution of the $Ξ^*(1530)$ and some background we are able to get a good reproduction of the mass distribution showing the signatures of the two resonances as found in the experiment.

hep-ph↗