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Zi-Ying Yang

Publications and source records attributed to Zi-Ying Yang.

6 recordsLinked to original sources
arXiv2026

Theoretical description of the $D^{+} \to \bar{K}^{0} π^{+} π^{0} π^{0}$ reaction

We study the $D^{+} \rightarrow \bar{K}^{0} π^{+} π^{0} π^{0}$ reaction, which shows two clear structures: the $\bar{K}^{*0}$ and $ρ^{+}$ in the $\bar{K}^{0} π^{0}$ and $π^{+} π^{0}$ mass distributions, respectively. The study is done starting from the quark level with external and internal emission and hadronizing a pair of quarks to produce a vector and two pseudoscalars. We also consider another mechanism, which does not require hadronization of quark pairs: the direct production of $\bar{K}^{*0}$ and $ρ^{+}$. With the help of six unknown parameters which are fitted to the data, we are able to get a very good agreement with experimental data for the $\bar{K}^{0} π^{0}$ and $π^{+} π^{0}$ mass distributions and a qualitative one for the rest of mass distributions which do not show any particular structure experimentally.

hep-ph↗
arXiv2025

Searching for the $2^+$ partner of the $T_{cs0}(2870)$ in the $B^- \to D^- D^0 K^0_S$ reaction

We study the $B^- \to D^- D^0 K^0_S$ reaction, recently analyzed by the LHCb collaboration, where a clear signal for the exotic $T_{cs0}(2870)$ state has been reported. We call the attention to a small peak in the $D^0 K^0_S$ mass distribution that could correspond to a state of the same nature as the $T_{cs0}(2870)$ ($D^* \bar K^*$ nature in the molecular picture) but with $J^P= 2^+$. In order to magnify the signal for the state, we calculate the moments of the angle-mass distribution, which are linear in the resonance signal, rather than quadratic for the angle integrated mass distribution. We find spectra for the moments with a strength far bigger than that for the angle integrated mass distribution, which should encourage the evaluation of these moments from the present measurements of the reaction.

hep-ph↗
arXiv2025

Role of $a_0( 1710)$ in the $D_s^+\toρ^+ϕ,~~ρ^+ω$ decays

We look into the $D_s^+ \to ρ^+ ϕ$ and $D_s^+ \to ρ^+ ω$ weak decays recently measured by the BESIII collaboration, which proceed very differently in a first step of the weak decay. While the first reaction proceeds directly via external emission, the second one does not go via external nor internal emission, what prompted the experimental team to claim that it proceeds via $W-$annihilation. We show in this work that the unexpectedly large rate of the $D_s^+ \to ρ^+ ω$, should it be due to $W-$annihilation, has a different explanation since is it naturally obtained once final state interaction of the $ρ^+ ϕ, ~ρ^+ ω$ and $K^{*+} \bar{K}^{*0}$ channels is taken into consideration. The interaction of these channels produces the $a_0(1710)$ resonance, predicted long ago as a molecular state of these coupled channels, and only recently observed, and it is the presence of this resonance what makes the effect of the final state interaction very important in the weak decays and provides a natural explanation of the experimental decay rates.

hep-ph↗
arXiv2025

Molecular $P_ψ$ pentaquarks from light-meson exchange saturation

Theoretical predictions for the spectrum of heavy meson-baryon bound states are a fundamental tool for disentangling the nature of the different pentaquark states that have been observed in experimental facilities. Here we explore this spectrum in a phenomenological model that describes the heavy meson-baryon interaction in terms of a contact-range interaction, where the coupling strength is saturated by the exchange of light scalar and vector mesons, i.e. $σ$, $ρ$ and $ω$ exchanges. Saturation determines the couplings modulo an unknown proportionality constant that can be calibrated from a molecular candidate. If we use the $P_ψ^N(4312)$ as input, we predict a series of molecular pentaquarks including the $P_ψ^N(4440)$ and $P_ψ^N(4457)$, the recent $P_{ψs}^Λ(4338)$ and the $P_{ψs}^Λ(4459)$.

hep-ph↗
arXiv2024

$P_c(4440)$ and $P_c(4457)$ decay into $\bar{D}Σ_c$ and $\bar{D}Λ_c$ and the spin of the $P_c$ states

We address the issue of the width and spin assignment of the $P_c(4440)$ and $P_c(4457)$ pentaquark states. We calculate the partial decays widths of the particles into $J/ψN$, $\bar{D} Σ_c$ and $\bar{D} Λ_c$ with the first one obtained within a unitary approach with the coupled channels of $J/ψN$ and $\bar{D}^* Σ_c$ with the interaction driven by vector meson exchange, and the last two by means of triangle diagrams involving pion exchange which break the spin degeneracy of the vector meson exchange. The widths obtained depend much on the spin of the particles and we study the possible scenarios for spin assignment, favoring the $1/2^-$ , $3/2^-$ order. We predict values for decays in different channels and show that their determination would allow to decide unambiguously the spin of the states.

hep-ph↗
arXiv2024

Searching for signals of an exotic $I=1,J^P=2^+$ state of $D^*K^*$ nature and the structure of the $P_c(4312)$ in the $Λ_b\to Σ_c^{++} D^- K^-$ reaction

This paper investigates the decay process $Λ_b \to Σ_c^{++} D^- K^-$ with the objective of finding a predicted molecular state with isospin $I=1$, $J^P=2^+$ of $D^* K^*$ nature, plus finding support for the $P_c(4312)$ state as made out of $Σ_c \bar{D}$. The mass distribution of the $D^- K^-$ system shows distinct features as a consequence of the existing of this $2^+$ state, while the $Σ_c \bar{D}$ distribution exhibits a significant peak near the threshold, much bigger than phase space expectations, which is linked to our assumed $Σ_c \bar{D}$ nature of the $P_c(4312)$ state below the $Σ_c \bar{D}$ threshold. The reaction has been measured at LHCb Collaboration, but only the branching ratio is measured. The present study shows that much valuable information can be obtained about the predicted $2^+$ $T_{c\bar{s}}(2834)$ of $D^* K^*$ nature and the $P_c(4312)$ states from the measurements of the mass distributions in this reaction, which will be accessible in the planned updates of LHCb.

hep-ph↗