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Z. H. Duan

Publications and source records attributed to Z. H. Duan.

385 records · Page 22Linked to original sources
arXiv2023

Search for hidden-charm tetraquark with strangeness in $e^{+}e^{-}\rightarrow K^+ D_{s}^{*-} D^{*0}+c.c.$

We report a search for a heavier partner of the recently observed $Z_{cs}(3985)^{-}$ state, denoted as $Z_{cs}^{\prime -}$, in the process $e^{+} e^{-}\rightarrow K^{+}D_{s}^{*-}D^{* 0}+c.c.$, based on $e^+e^-$ collision data collected at the center-of-mass energies of $\sqrt{s}=4.661$, 4.682 and 4.699 GeV with the BESIII detector. The $Z_{cs}^{\prime -}$ is of interest as it is expected to be a candidate for a hidden-charm and open-strange tetraquark. A partial-reconstruction technique is used to isolate $K^+$ recoil-mass spectra, which are probed for a potential contribution from $Z_{cs}^{\prime -}\to D_{s}^{*-}D^{* 0}$ ($c.c.$). We find an excess of $Z_{cs}^{\prime -}\rightarrow D_{s}^{*-}D^{*0}$ ($c.c.$) candidates with a significance of $2.1σ$, after considering systematic uncertainties, at a mass of $(4123.5\pm0.7_\mathrm{stat.}\pm4.7_\mathrm{syst.})\ \mathrm{MeV}/c^{2}$. As the data set is limited in size, the upper limits are evaluated at the 90\% confidence level on the product of the Born cross sections ($σ^{\mathrm{Born}}$) and the branching fraction ($\mathcal{B}$) of $Z_{cs}^{\prime-}\rightarrow D_{s}^{*-}D^{* 0}$, under different assumptions of the $Z_{cs}^{\prime -}$ mass from 4.120 to 4.140 MeV and of the width from 10 to 50 MeV at the three center-of-mass energies. The upper limits of $σ^{\rm Born}\cdot\mathcal{B}$ are found to be at the level of $\mathcal{O}(1)$ pb at each energy. Larger data samples are needed to confirm the $Z_{cs}^{\prime -}$ state and clarify its nature in the coming years.

hep-ex↗
arXiv2022

Observation of the $J/ψ$ and $ψ(3686)$ decays into $ηΣ^{+}\barΣ^{-}$

The decays $J/ψ\toηΣ^{+}\barΣ{}^-$ and $ψ(3686)\toηΣ^{+}\barΣ{}^-$ are observed for the first time, using $(10087 \pm 44)\times 10^{6}$ $J/ψ$ and $(448.1 \pm 2.9)\times 10^{6}$ $ψ(3686)$ events collected with the BESIII detector at the BEPCII collider. We determine the branching fractions of these two decays to be ${\cal B}(J/ψ\toηΣ^{+}\barΣ{}^-)=(6.34 \pm 0.21 \pm 0.37)\times 10^{-5}$ and ${\cal B}(ψ(3686)\toηΣ^{+}\barΣ{}^-)=(9.59 \pm 2.37 \pm 0.61)\times 10^{-6}$, where the first uncertainties are statistical and the second are systematic. The ratio of these two branching fractions is determined to be $\frac{{\cal B}(ψ(3686)\toηΣ^{+}\barΣ{}^-)}{{\cal B}(J/ψ\toηΣ^{+}\barΣ{}^-)}=(15.1 \pm 3.8)\%$, which is in agreement with the "12\% rule."

hep-ex↗
arXiv2022

Observations of the Cabibbo-Suppressed decays $Λ_{c}^{+}\to nπ^{+}π^{0}$, $nπ^{+}π^{-}π^{+}$ and the Cabibbo-Favored decay $Λ_{c}^{+}\to nK^{-}π^{+}π^{+}$

Using electron-positron annihilation data samples corresponding to an integrated luminosity of 4.5 $\rm{{fb}^{-1}}$, collected by the BESIII detector in the energy region between $4600$ MeV and $4699$ MeV, we report the first observations of the Cabibbo-suppressed decays $Λ_c^+\to nπ^+π^0$, $Λ_c^+\to nπ^+π^-π^+$, and the Cabibbo-favored decay $Λ_c^+\to nK^-π^+π^+$ with statistical significances of $7.9σ$, $7.8σ$, and $>10σ$, respectively. The branching fractions of these decays are measured to be $\mathcal{B}(Λ_{c}^{+}\rightarrow nπ^{+}π^{0})=(0.64\pm0.09\pm0.02)\%$, $\mathcal{B}(Λ_{c}^{+}\rightarrow nπ^{+}π^{-}π^{+})=(0.45\pm0.07\pm0.03)\%$, and $\mathcal{B}(Λ_{c}^{+}\rightarrow nK^{-}π^{+}π^{+})=(1.90\pm0.08\pm0.09)\%$, where the first uncertainties are statistical and the second are systematic. We find that the branching fraction of the decay $Λ_{c}^{+}\rightarrow nπ^{+}π^{0}$ is about one order of magnitude higher than that of $Λ_{c}^{+}\rightarrow nπ^{+}$.

hep-ex↗
arXiv2022

Determination of U-spin breaking parameters with an amplitude analysis of the decay $D^0 \to K_{\rm L}^0π^+π^-$

We present a study of the resonant structure of the decay $D^0 \to K_{\rm L}^0π^+π^-$, using quantum-correlated $D^0\bar{D}^0$ data produced at $\sqrt{s}=3.773$ GeV. The data sample was collected by the BESIII experiment and corresponds to an integrated luminosity of $2.93$ fb$^{-1}$. This study is the first amplitude analysis of a decay mode involving a $K_{\rm L}^0$, which also results in the first measurement of the complex $\textit{U-spin breaking parameters}$ ($\hatρ$) related to various $\mathit{CP}$-eigenstate resonant modes through which the three-body decay proceeds. The moduli of the $\hatρ$ parameters have central values in a wide range from $0.4$ to $12.1$, which indicates substantial U-spin symmetry breaking. We present the fractional resonant contributions and average strong-phase parameters over regions of phase space for both $K_{\rm S}^0π^+π^-$ and $K_{\rm L}^0π^+π^-$ modes. We also report the ratio of the branching fractions between $K_{\rm L}^0π^+π^-$ and $K_{\rm S}^0π^+π^-$ decay modes and the $\mathit{CP}$-even fraction of the $K_{\rm L}^0π^+π^-$ state calculated using the U-spin breaking parameters.

hep-ex↗
arXiv2022

First Direct Measurement of the Absolute Branching Fraction of $Σ^+ \to Λe^+ ν_{e}$

The first direct measurement of the absolute branching fraction of $Σ^+ \to Λe^+ ν_{e}$ is reported based on an $e^+e^-$ annihilation sample of $(10087\pm44) \times 10^6$ $J/ψ$ events collected with the BESIII detector at $\sqrt{s}=3.097$ GeV. The branching fraction is determined to be ${\mathcal B}(Σ^+ \to Λe^+ ν_{e}) = [2.93\pm0.74(\rm stat) \pm 0.13(\rm syst)]\times 10^{-5}$, which is the most precise measurement obtained in a single experiment to date and also the first result obtained at a collider experiment. Combining this result with the world average of ${\mathcal B}(Σ^- \to Λe^- \barν_{e})$ and the lifetimes of $Σ^{\pm}$, the ratio, $\frac{Γ(Σ^- \to Λe^- \barν_{e})}{Γ(Σ^+ \to Λe^+ ν_{e})}$, is determined to be $1.06 \pm 0.28$, which is within 1.8 standard deviations of the value expected in the absence of second-class currents that are forbidden in the Standard Model.

hep-ex↗
arXiv2022

Observation of $Ξ^{-}$ Hyperon Transverse Polarization in $ψ(3686)\rightarrowΞ^{-}\barΞ^{+}$

Using a sample of $(448.1~\pm~2.9)$ $\times 10^{6}$ $ψ(3686)$ decays collected with the BESIII detector at BEPCII, we report an observation of $Ξ^{-}$ transverse polarization with a significance of $7.3 σ$ in the decay $ψ(3686)\rightarrowΞ^{-}\barΞ^{+}$ ($Ξ^{-}\rightarrowπ^{-}Λ$, $\barΞ^{+}\rightarrowπ^{+}\barΛ$, $Λ\to pπ^{-}$, $\barΛ\to\bar{p}π^{+}$). The relative phase of the electric and magnetic form factors is determined to be $ΔΦ= (0.667 \pm 0.111 \pm 0.058)$ rad. This is the first measurement of the relative phase for a $ψ(3686)$ decay into a pair of $Ξ^{-}\barΞ^{+}$ hyperons. The $Ξ^{-}$ decay parameters ($α_{Ξ^{-}}$, $ϕ_{Ξ^-}$) and their conjugates ($α_{\barΞ^{+}}$, $ϕ_{\barΞ^{+}}$), the angular-distribution parameter $α_ψ$, and the strong-phase difference $δ_{p}-δ_{s}$ for $Λ$-$π^-$ scattering are measured to be consistent with previous BESIII results.

hep-ex↗
arXiv2022

Measurement of $e^+e^-\rightarrowΛ\barΛη$ from 3.5106 to 4.6988 GeV and study of $Λ\barΛ$ mass threshold enhancement

Using data samples with a total integrated luminosity of approximately 18 fb$^{-1}$ collected by the BESIII detector operating at the BEPCII, the process $e^+e^-\rightarrowΛ\barΛ η$ is studied at center-of-mass energies between 3.5106 and 4.6988 GeV. The Born cross section for the process $e^+e^-\rightarrowΛ\barΛη$ is measured. No significant structure is observed in the Born cross section line shape. An enhancement near the $Λ\barΛ$ mass threshold is observed for the first time in the process. The structure can be described by an $S$-wave Breit-Wigner function. Neglecting contribution of excited $Λ$ states and potential interferences, the mass and width are determined to be ($2356\pm 7\pm17$) MeV/$c^2$ and ($304\pm28\pm54$) MeV, respectively, where the first uncertainties are statistical and the second are systematic.

hep-ex↗