arXiv subjects

X. F. Cui

Publications and source records attributed to X. F. Cui.

At least 19 recordsLinked to original sources

arXiv2024

Observation of the Electromagnetic Dalitz Transition $h_c \rightarrow e^+e^-\eta_c$

Using $(27.12\pm 0.14)\times10^8$ $\psi(3686)$ decays and data samples of $e^+e^-$ collisions with $\sqrt{s}$ from 4.130 to 4.780~GeV collected with the BESIII detector, we report the first observation of the electromagnetic Dalitz transition $h_c\to e^+e^-\eta_c$ with a statistical significance of $5.4\sigma$. We measure the ratio of the branching fractions $\frac{\mathcal{B}(h_c\rightarrow e^+e^-\eta_c)}{\mathcal{B}(h_c\rightarrow \gamma \eta_c)}$ separately for the $h_c$ samples produced via $\psi(3686)\to\pi^0h_c$ and $e^+e^-\to\pi^+\pi^-h_c$. The average ratio is determined to be $(0.59\pm0.10(\text{stat.})\pm0.04(\text{syst.}))\%$, where the uncertainty includes both statistical and systematic components.

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arXiv2023

Partial wave analysis of $J/ψ\rightarrowγηη'$

Based on a sample of (10.09$\pm$0.04)$\times$10$^{9}$ $J/ψ$ events collected with the BESIII detector operating at the BEPCII storage ring, a partial wave analysis of the decay $J/ψ\rightarrow γηη'$ is performed. An isoscalar state with exotic quantum numbers $J^{PC}=1^{-+}$, denoted as $η_1(1855)$, has been observed for the first time with statistical significance larger than 19$σ$. Its mass and width are measured to be (1855$\pm$9$_{-1}^{+6}$)~MeV/$c^{2}$ and (188$\pm$18$_{-8}^{+3}$)~MeV, respectively. The product branching fraction ${\cal B}(J/ψ$$\rightarrow$$ γη_1(1855)$$\rightarrow$$γηη')$ is measured to be (2.70$\pm 0.41 _{-0.35}^{+0.16}) \times$10$^{-6}$. The first uncertainties are statistical and the second are systematic. In addition, an upper limit on the branching ratio ${\cal B}(f_0(1710)$$\rightarrow$$ηη')$/${\cal B}(f_0(1710)$$\rightarrow$$ππ)$ is determined to be $1.61 \times 10^{-3}$ at 90\% confidence level, which lends support to the hypothesis that the $f_0(1710)$ has a large glueball component.

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arXiv2023

Observation of an isoscalar resonance with exotic $J^{PC}=1^{-+}$ quantum numbers in $J/ψ\rightarrowγηη'$

Using a sample of (10.09$\pm$0.04)$\times$10$^{9}$ $J/ψ$ events collected with the BESIII detector operating at the BEPCII storage ring, a partial wave analysis of the decay $J/ψ\rightarrow γηη'$ is performed. The first observation of an isoscalar state with exotic quantum numbers $J^{PC}=1^{-+}$, denoted as $η_1(1855)$, is reported in the process $J/ψ\rightarrow γη_1(1855)$ with $η_1(1855)\rightarrowηη'$. Its mass and width are measured to be (1855$\pm$9$_{-1}^{+6}$)MeV/$c^{2}$ and (188$\pm$18$_{-8}^{+3}$)MeV, respectively, where the first uncertainties are statistical and the second are systematic, and its statistical significance is estimated to be larger than 19$σ$.

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arXiv2022

Measurement of the branching fraction for $ψ(3686)\to ωK^0_SK^0_S$

Analyzing $(448.1\pm2.9)\times10^6$ $ψ(3686)$ events collected with the BESIII detector at the BEPCII collider, the $ψ(3686)\to ωK_{S}^{0}K_{S}^{0}$ decay is observed for the first time. The branching fraction for this decay is determined to be $\mathcal{B}_{ψ(3686)\to ωK_{S}^{0}K^{0}_{S}}$=$(7.04\pm0.39\pm0.36)$$\times10^{-5}$, where the first uncertainty is statistical and the second is systematic.

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arXiv2022

Search for the decay $h_c\rightarrowπ^0J/ψ$

A search for the decay $h_c\rightarrowπ^0J/ψ$ is performed using a sample of $h_c$ produced in the reaction $e^+e^-\rightarrowπ^+π^-h_c$. The data samples were collected with the BESIII detector at center-of-mass energies between 4.189 and 4.437 GeV, corresponding to a total integrated luminosity of 11 fb$^{-1}$. No significant signal is observed. Upper limits on the branching ratio $\mathcal{B}(h_c\rightarrowπ^0J/ψ)/\mathcal{B}(h_c\rightarrowγη_c\rightarrowγK^+K^-π^0)$ and on the branching fraction $\mathcal{B}(h_c\rightarrowπ^0J/ψ)$ are determined to be $7.5\times10^{-2}$ and $4.7\times10^{-4}$ at $90\%$ confidence level, respectively. The latter is derived from the former using the measured branching fraction of the normalization channel. This is the first determination of the upper limit of the decay $h_c\rightarrowπ^0J/ψ$.

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arXiv2022

Search for new hadronic decays of $h_{c}$ and observation of $h_{c}\to p\bar{p}η$

A search for the hadronic decays of the $h_{c}$ meson to the final states $p\bar{p}π^{+}π^{-}π^{0}$, $p\bar{p}η$, and $p\bar{p}π^0$ via the process $ψ(3686) \to π^{0}{h_c}$ is performed using $(4.48\pm0.03)\times10^{8}$ $ψ(3686)$ events collected with the BESIII detector. The decay channel $h_{c}\to p\bar{p}η$ is observed for the first time with a significance greater than $5σ$ and a branching fraction of $\left( {6.41 \pm 1.74 \pm 0.53 \pm 1.00} \right) \times {10^{ -4}}$, where the uncertainties are statistical, systematic, and that from the branching fraction of $ψ(3686)\toπ^{0}h_{c}$. Strong evidence for the decay ${h_c} \to p\bar{p}{π^+}{π^-}{π^0}$ is found with a significance of $4.9σ$ and a branching fraction of $\left( {3.84 \pm 0.83 \pm0.69} \pm 0.58 \right) \times {10^{ - 3}}$. The significances include systematic uncertainties. No clear signal of the decay $h_c\to p\bar{p}π^{0}$ is found, and an upper limit of $6.59\times 10^{-4}$ on its branching fraction is set at the 90% confidence level.

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arXiv2022

Amplitude analysis and branching fraction measurement of $D_{s}^{+} \to K^-K^+π^+π^+π^-$

Using $e^{+}e^{-}$ annihilation data corresponding to a total integrated luminosity of $6.32$ fb$^{-1}$ collected at the center-of-mass energies between 4.178 and 4.226 GeV with the BESIII detector, we perform an amplitude analysis of the decay $D^+_s \to K^-K^+π^+π^+π^-$ and determine the relative fractions and phases of different intermediate processes. Absolute branching fraction of $D^+_s\to K^-K^+π^+π^+π^-$ decay is measured to be ($6.60\pm0.47_{\rm stat.}\pm0.35_{\rm syst.})\times 10^{-3}$. The dominant intermediate process is $D_{s}^{+} \to a_1(1260)^+ϕ, ϕ\to K^-K^+, a_1(1260)^+\to ρπ^+, ρ\toπ^+π^-$, with a branching fraction of $(5.16\pm0.41_{\rm stat.}\pm0.27_{\rm syst.})\times 10^{-3}$.

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arXiv2022

Measurement of the $D \to K^-π^+π^+π^-$ and $D \to K^-π^+π^0$ coherence factors and average strong-phase differences in quantum-correlated ${D\bar{D}}$ decays

The decays $D\to K^-π^+π^+π^-$ and $D \to K^-π^+π^0$ are studied in a sample of quantum-correlated $D\bar{D}$ pairs produced through the process $e^+e^- \to ψ(3770) \to D\bar{D}$, exploiting a data set collected by the BESIII experiment that corresponds to an integrated luminosity of 2.93 fb$^{-1}$. Here $D$ indicates a quantum superposition of a $D^0$ and a $\bar{D}^0$ meson. By reconstructing one neutral charm meson in a signal decay, and the other in the same or a different final state, observables are measured that contain information on the coherence factors and average strong-phase differences of each of the signal modes. These parameters are critical inputs in the measurement of the angle $γ$ of the Unitarity Triangle in $B^- \to DK^-$ decays at the LHCb and Belle II experiments. The coherence factors are determined to be $R_{K3π}=0.52^{+0.12}_{-0.10}$ and $R_{Kππ^0}=0.78 \pm 0.04$, with values for the average strong-phase differences that are $δ_D^{K3π}=\left(167^{+31}_{-19}\right)^\circ$ and $δ_D^{Kππ^0}=\left(196^{+14}_{-15}\right)^\circ$, where the uncertainties include both statistical and systematic contributions. The analysis is re-performed in four bins of the phase-space of the $D \to K^-π^+π^+π^-$ to yield results that will allow for a more sensitive measurement of $γ$ with this mode, to which the BESIII inputs will contribute an uncertainty of around 6$^\circ$.

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arXiv2021

First measurement of polarizations in the decay $D^0 \to ωϕ$

Using a data sample corresponding to an integrated luminosity of 2.93 fb$^{-1}$ collected at a center-of-mass energy $\sqrt{s}=3.773$ GeV by the BESIII detector, the decay $D^0 \toωϕ$ is observed for the first time. The branching fraction is measured to be $(6.48 \pm 0.96 \pm 0.40)\times 10^{-4}$ with a significance of $6.3 σ$, where the first and second uncertainties are statistical and systematic, respectively. An angular analysis reveals that the $ϕ$ and $ω$ mesons from the $D^0 \to ωϕ$ decay are transversely polarized. The $95\%$ confidence level upper limit on longitudinal polarization fraction is set to be less than $0.24$, which is inconsistent with current theoretical expectations and challenges our understanding of the underlying dynamics in charm meson decays.

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arXiv2021

Cross sections for the reactions $e^+e^-\rightarrow K^+K^-π^+π^-(π^0)$, $K^+K^-K^+K^-(π^0)$, $π^+π^-π^+π^-(π^0)$, $p\bar{p}π^+π^-(π^0)$ in the energy region between 3.773 and 4.600 GeV

Using the data samples collected in the energy range from 3.773 to 4.600 GeV with the BESIII detector at the BEPCII collider, we measure the dressed cross sections as a function of center-of-mass energy for $e^+e^-\rightarrow K^+K^-π^+π^-(π^0)$, $K^+K^-K^+K^-(π^0)$, $π^+π^-π^+π^-(π^0)$, and $p\bar{p}π^+π^-(π^0)$. The cross sections for $e^+e^-\rightarrow K^+K^-K^+K^-π^0$, $p\bar{p}π^+π^-(π^0)$ are the first measurements. Cross sections for the other five channels are much more precise than previous results in this energy region. We also search for charmonium and charmonium-like resonances, such as the $Y(4230)$, decaying into the same final states. We find evidence of the $ψ(4040)$ decaying to $π^+π^-π^+π^-π^0$ with a statistical significance of $3.6σ$. Upper limits are provided for other decays since no clear signals are observed.

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arXiv2021

Observation of the Decay $D^0\to ρ^-μ^+ν_μ$

By analyzing an $e^+e^-$ annihilation data sample corresponding to an integrated luminosity of $2.93~\mathrm{fb}^{-1}$ collected at a center-of-mass energy of 3.773 GeV with the BESIII detector, we measure the branching fraction of the $D^0\to ρ^- μ^+ν_μ$ decay for the first time. We obtain ${\mathcal B}_{D^0\to ρ^- μ^+ν_μ}=(1.35\pm0.09_{\rm stat}\pm0.09_{\rm syst})\times 10^{-3}$. Using the world average of ${\mathcal B}_{D^0\to ρ^- e^+ν_e}$, we find a branching fraction ratio of ${\mathcal B}_{D^0\to ρ^- μ^+ν_μ}/{\mathcal B}_{D^0\to ρ^- e^+ν_e}=0.90\pm0.11$, which agrees with the theoretical expectation of lepton flavor universality within the uncertainty. Combining the world average of ${\mathcal B}_{D^+\to ρ^0 μ^+ ν_μ}$ and the lifetimes of $D^{0(+)}$, we obtain a partial decay width ratio of $Γ_{D^0\to ρ^- μ^+ ν_μ}/(2Γ_{D^+\to ρ^0 μ^+ ν_μ}) = 0.71\pm0.14$, which is consistent with the isospin symmetry expectation of one within $2.1σ$. For the reported values of ${\mathcal B}_{D^0\to ρ^- μ^+ν_μ}/{\mathcal B}_{D^0\to ρ^- e^+ν_e}$ and $Γ_{D^0\to ρ^- μ^+ ν_μ}/2Γ_{D^+\to ρ^0 μ^+ ν_μ}$, the uncertainty is the quadratic sum of the statistical and systematic uncertainties.

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arXiv2021

Measurement of the cross section for $e^{+}e^{-}\rightarrowΛ\barΛ$ and evidence of the decay $ψ(3770)\rightarrowΛ\barΛ$

The Born cross section of the process $e^{+}e^{-}\rightarrowΛ\barΛ$ is measured at 33 center-of-mass energies between 3.51 and 4.60 GeV using data corresponding to the total integrated luminosity of 20.0 fb$^{-1}$ collected with the BESIII detector at the BEPCII collider. Describing the energy dependence of the cross section requires a contribution from the $ψ(3770)\rightarrowΛ\barΛ$ decay, which is fitted with a significance of 4.6-4.9$σ$ including the systematic uncertainty. The lower bound on its branching fraction is $2.4\times10^{-6}$ at the 90% confidence level (C.L.), at least an order of magnitude larger than expected from predictions using a scaling based on observed electronic widths. This result indicates the importance of effects from vector charmonium(-like) states when interpreting data in terms of e.g., electromagnetic structure observables. The data do not allow for definite conclusions on the interplay with other vector charmonium(-like) states, and we set 90% C.L.upper limits for the products of their electronic widths and the branching fractions.

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arXiv2021

Measurement of the Born cross sections for $e^+e^- \to η^\prime π^{+}π^{-}$ at center-of-mass energies between $2.00$ and $3.08$ GeV

The Born cross sections for the process $e^+e^- \to η^\prime π^{+}π^{-}$ at different center-of-mass energies between $2.00$ and $3.08$ GeV are reported with improved precision from an analysis of data samples collected with the BESIII detector operating at the BEPCII storage ring. An obvious structure is observed in the Born cross section line shape. Fit as a Breit-Wigner resonance, it has a statistical significance of $6.3σ$ and a mass and width of $M=(2111\pm43\pm25)$~MeV/$c^2$ and $Γ=(135\pm34\pm30)$~MeV, where the uncertainties are statistical and systematic, respectively. These measured resonance parameters agree with the measurements of BABAR in $e^+e^- \to η^\prime π^{+}π^{-}$ and BESIII in $e^+e^- \to ωπ^0$ within two standard deviations.

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arXiv2021

Measurement of $e^+e^-\toγχ_{c0,c1,c2}$ cross sections at center-of-mass energies between 3.77 and 4.60 GeV

The $e^+e^-\toγχ_{cJ}$ ($J=0,1,2$) processes are studied at center-of-mass energies ranging from 3.773 to 4.600 GeV, using a total integrated luminosity of 19.3 fb$^{-1}$ $e^+e^-$ annihilation data accumulated with the BESIII detector at BEPCII. We observe for the first time $e^+e^-\toγχ_{c1,c2}$ signals at $\sqrt{s}=$ 4.180 GeV with statistical significances of 7.6$σ$ and 6.0$σ$, respectively. The production cross section of $e^+e^-\toγχ_{c1,c2}$ at each center-of-mass energy is also measured. We find that the line shape of the $e^+e^-\toγχ_{c1}$ cross section can be described with conventional charmonium states $ψ(3686)$, $ψ(3770)$, $ψ(4040)$, $ψ(4160)$. Compared with this, for the $e^+e^-\toγχ_{c2}$ channel, one more additional resonance is added to describe the cross section line shape. Its mass and width are measured to be $M=4371.7\pm7.5\pm1.8$ MeV/$c^2$ and $Γ^{tot}=51.1\pm17.6\pm1.9$ MeV, where the first uncertainties are statistical and the second systematic. The significance of this resonance is estimated to be 5.8$σ$, and its parameters agree with the $Y(4360)$ resonance previously reported in $e^+e^-\toπ^+π^-ψ(3686)$, and the $Y(4390)$ in $e^+e^-\toπ^+π^-h_c$ within uncertainties. No significant signal for the $e^+e^-\toγχ_{c0}$ process is observed, and the upper limits of Born cross sections $σ_{B}(e^+e^-\toγχ_{c0})$ at 90\% confidence level are reported.

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arXiv2021

Measurement of the Absolute Branching Fraction of $D_s^+ \to τ^+ ν_τ$ via $τ^+ \to e^+ ν_e \barν_τ$

Using a dataset of 6.32 fb$^{-1}$ of $e^+ e^-$ annihilation data collected with the BESIII detector at center-of-mass energies between 4178 and 4226 MeV, we have measured the absolute branching fraction of the leptonic decay $D_s^+ \to τ^+ ν_τ$ via $τ^+ \to e^+ ν_e \barν_τ$, and find $\mathcal{B}_{D_s^+ \to τ^+ ν_τ}=(5.27\pm0.10\pm0.12)\times10^{-2}$, where the first uncertainty is statistical and the second is systematic. The precision is improved by a factor of 2 compared to the previous best measurement. Combining with $f_{D_s^+}$ from Lattice quantum chromodynamics calculations or the $|V_{cs}|$ from the CKMfitter group, we extract $|V_{cs}|=0.978\pm0.009\pm0.012$ and $f_{D_s^+}= (251.1\pm2.4\pm3.0)$ MeV, respectively. Combining our result with the world averages of $\mathcal{B}_{D_s^+ \to τ^+ ν_τ}$ and $\mathcal{B}_{D_s^+ \to μ^+ ν_μ}$, we obtain the ratio of the branching fractions $\mathcal{B}_{D_s^+ \to τ^+ ν_τ} / \mathcal{B}_{D_s^+ \to μ^+ ν_μ} = 9.72\pm0.37$, which is consistent with the standard model prediction of lepton flavor universality.

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arXiv2021

Study of the Dalitz decay $J/ψ\to e^+e^- η$

We report corrected results on a study of the electromagnetic Dalitz decay $J/ψ\to e^+e^- η$ and search for di-electron decays of a light dark gauge boson ($γ'$) in $J/ψ\to γ' η$ with the two $η$ decay modes $η\rightarrow γγ$ and $η\rightarrow π^+π^-π^0$, using $(1310.6\pm 7.0)\times10^6$ $J/ψ$ events collected with the BESIII detector. In particular we update the measurement of the pole mass of the transition form factor (TFF) of $J/ψ\to e^+e^- η$ to be $Λ= 2.56 \pm 0.04({\rm stat}) \pm 0.03({\rm syst})$ GeV/$c^2$. The branching fraction of $J/ψ\to e^+e^-η$ and the kinetic-mixing strength between the Standard Model photon and $γ'$ are also updated after taking the corrected $Λ$ value into account. The measured branching fraction of $J/ψ\to e^+e^- η$ is updated to be $(1.42 \pm 0.04({\rm stat}) \pm 0.07 ({\rm syst}))\times 10^{-5}$, where the first and second uncertainties are statistical and systematic, respectively.

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arXiv2021

Measurement of Branching Fractions of $J/ψ$ and $ψ(3686)$ decays to $Σ^{+}$ and $\overlineΣ^-$

Using $1310.6\times10^{6}$ $J/ψ$ and $448.1\times10^{6}$ $ψ(3686)$ events collected with the BESIII detector, the branching fractions of $J/ψ$ and $ψ(3686)$ decays to $Σ^{+}\overlineΣ^{-}$ are measured to be $(10.61 \pm 0.04 \pm 0.36) \times 10^{-4}$ and $(2.52 \pm 0.04 \pm 0.09) \times 10^{-4}$, respectively. In addition, the ratio of $\mathcal{B}(ψ(3686) \rightarrow Σ^{+}\overlineΣ^{-})/\mathcal{B}(J/ψ\rightarrow Σ^{+}\overlineΣ^{-})$ is determined to be $(23.8 \pm 1.1)\%$ which violates the "$12\%$ rule".

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arXiv2021

Measurement of the $e^{+}e^{-}\toΣ^{0}\barΣ^{0}$ cross sections at center-of-mass energies from $2.3864$ to $3.0200$ GeV

The Born cross sections of $e^{+}e^{-}\to Σ^{0}\barΣ^{0}$ are measured at center-of-mass energies from $2.3864$ to $3.0200$ GeV using data samples with an integrated luminosity of $328.5$ pb$^{-1}$ collected with the BESIII detector operating at the BEPCII collider. The analysis makes use of a novel reconstruction method for energies near production threshold, while a single-tag method is employed at other center-of-mass energies. The measured cross sections are consistent with earlier results from BaBar, with a substantially improved precision. The cross-section lineshape can be well described by a perturbative QCD-driven energy function. In addition, the effective form factors of the $Σ^{0}$ baryon are determined. The results provide precise experimental input for testing various theoretical predictions.

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