arXiv subjects

R. A. Briere

Publications and source records attributed to R. A. Briere.

At least 307 records · Page 17Linked to original sources

arXiv2024

Search for lepton flavor-violating decay modes $B^0\to K_S^0τ^\pm\ell^\mp~(\ell=μ, e)$ with hadronic $B$-tagging at Belle and Belle II

We present the first search for the lepton flavor-violating decay modes $B^0 \rightarrow K_S^0 τ^\pm \ell^\mp~(\ell=μ, e)$ using the 711 fb$^{-1}$ and 365 fb$^{-1}$ data samples recorded by the Belle and Belle II detectors, respectively. We use a hadronic $B$-tagging technique, and search for the signal decay in the system recoiling against the fully reconstructed $B$ meson. We find no evidence for $B^0 \rightarrow K_S^0 τ^\pm \ell^\mp$ decays and set 90\% confidence level upper limits on the branching fractions in the range of $[0.8,\,3.6]\times10^{-5}$.

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arXiv2024

Measurement of the Branching Fraction for the Decay $χ_{cJ}\to p\bar{p}ηπ^{0}$

Using $(2712.4\pm 14.3)\times10^6 ψ(3686)$ events collected by the BESIII detector operating at the BEPCII collider, we present the first observations of the decays $χ_{cJ}(J=0,1,2)\to p\bar{p}ηπ^{0}$. Their decay branching fractions are determined to be ${\cal B}(χ_{c0}\to p\bar{p}ηπ^{0})=({2.41 \pm 0.07 \pm 0.19}) \times 10^{-4}$, ${\cal B}(χ_{c1}\to p\bar{p}ηπ^{0})=({1.95 \pm 0.05 \pm 0.12}) \times 10^{-4}$, and ${\cal B}(χ_{c2}\to p\bar{p}ηπ^{0})=({1.31 \pm 0.05 \pm 0.08}) \times 10^{-4}$, where the first uncertainties are statistical and the second systematic.

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arXiv2024

Measurement of the branching fraction and $\it CP$-violating asymmetry of the decay $B^{0} \rightarrow π^{0} π^{0}$ using $387$ million bottom-antibottom meson pairs in Belle II data

We measure the branching fraction and $\it CP$-violating flavor-dependent rate asymmetry of $B^{0} \to π^{0} π^{0}$ decays reconstructed using the Belle II detector in an electron-positron collision sample containing $387 \times 10^{6}$ $B\overline{B}$ pairs. Using an optimized event selection, we find $126\pm 20$ signal decays in a fit to background-discriminating and flavor-sensitive distributions. The resulting branching fraction is $(1.25 \pm 0.23)\times 10^{-6}$ and the $\it CP$-violating asymmetry is $0.03 \pm 0.30$.

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arXiv2024

Study of $D_{s}^{+} \rightarrow f_{0}(980)ρ^+$ and $ϕπ^+$ decays through $D_{s}^{+}\rightarrow π^{+}π^{+}π^{-}π^{0}$

We perform the first amplitude analysis of $D^+_s \to π^+π^+π^-π^0$ decays, based on data samples of electron-positron collisions recorded with the BESIII detector at center-of-mass energies between 4.128 and 4.226~GeV, corresponding to an integrated luminosity of 7.33~fb$^{-1}$. We report the observation of $D_{s}^{+} \to f_0(980)ρ(770)^{+}$ with a statistical significance greater than 10$σ$ and determine the branching fractions $\mathcal{B}(D_s^+\toπ^+π^+π^-π^0|_{{\rm non}-η})=(2.04\pm0.08_{\rm stat.}\pm0.05_{\rm syst.})\%$ and $\mathcal{B}(D_s^+\toηπ^+)=(1.56\pm0.09_{\rm stat.}\pm0.04_{\rm syst.})\%$. Moreover, we measure the relative branching fraction between $ϕ\toπ^+π^-π^0$ and $ϕ\to K^+K^-$ to be $\frac{\mathcal{B}(ϕ(1020) \to π^+π^-π^0)}{\mathcal{B}(ϕ(1020) \to K^+K^-)}=0.230 \pm 0.014_{\rm stat.} \pm 0.010_{\rm syst.}$, which deviates from the world average value by more than $4σ$.

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arXiv2024

Amplitude analysis and branching fraction measurement of the Cabibbo-favored decay $D^+ \to K^-π^+π^+π^0$

An amplitude analysis of the Cabibbo-favored decay $D^+ \to K^-π^+π^+π^0$ is performed, using 7.93 $\rm{fb}^{-1}$ of $e^+e^-$ collision data collected with the BESIII detector at the center-of-mass energy of 3.773 GeV. The branching fractions of the intermediate processes are measured, with the dominant contribution $D^+ \to \bar{K}^{*}(892)^0ρ(770)^+$ observed to have a branching fraction of $(4.15\pm0.07_{\rm stat.}\pm0.17_{\rm syst.})\%$. With the detection efficiency derived from the amplitude analysis, the absolute branching fraction of $D^+ \to K^-π^+π^+π^0$ is measured to be $(6.06\pm0.04_{\rm stat.}\pm0.07_{\rm syst.})\%$.

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arXiv2024

Search for $h_c \to π^+π^-J/ψ$ via $ψ(3686)\to π^0h_c$

Using $(2712.4 \pm 14.3) \times 10^6~ψ$(3686) events collected with the BESIII detector operating at the BEPCII collider, we search for the hadronic transition $h_c \to π^+π^-J/ψ$ via $ψ(3686)\to π^0 h_c$. No significant signal is observed. We set the most stringent upper limits to date on the branching fractions $\mathcal{B}(ψ(3686)\to π^0 h_c)\times\mathcal{B}(h_c\toπ^+π^-J/ψ)$ and $\mathcal{B}(h_c \to π^+π^-J/ψ)$ at the 90$\%$ confidence level, which are determined to be $6.7\times 10^{-7}$ and $9.4 \times10^{-4}$, respectively.

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arXiv2024

Observations of the singly Cabibbo-suppressed decays $Ξ_c^{+} \to pK_{S}^{0}$, $Ξ_c^+ \to Λπ^+$, and $Ξ_c^+ \to Σ^{0} π^+$ at Belle and Belle II

Using data samples of 983.0~$\rm fb^{-1}$ and 427.9~$\rm fb^{-1}$ accumulated with the Belle and Belle~II detectors operating at the KEKB and SuperKEKB asymmetric-energy $e^+e^-$ colliders, singly Cabibbo-suppressed decays $Ξ_c^{+} \to pK_{S}^{0}$, $Ξ_c^+ \to Λπ^+$, and $Ξ_c^+ \to Σ^{0} π^+$ are observed for the first time. The ratios of branching fractions of $Ξ_{c}^{+}\to p K_{S}^{0}$, $Ξ_{c}^{+}\to Λπ^{+}$, and $Ξ_{c}^{+}\to Σ^{0} π^{+}$ relative to that of $Ξ_c^+ \to Ξ^- π^{+} π^{+}$ are measured to be \begin{equation} \frac{{\cal B}(Ξ_c^+ \to pK_S^0)}{{\cal B}(Ξ_c^{+} \to Ξ^{-} π^+ π^+)} = (2.47 \pm 0.16 \pm 0.07)\% \notag, \end{equation} \begin{equation} \frac{{\cal B}(Ξ_c^+ \to Λπ^+)}{{\cal B}(Ξ_c^{+} \to Ξ^{-} π^+ π^+)} = (1.56 \pm 0.14 \pm 0.09)\% \notag, \end{equation} \begin{equation} \frac{{\cal B}(Ξ_c^+ \to Σ^0 π^+)}{{\cal B}(Ξ_c^{+} \to Ξ^{-} π^+ π^+)} = (4.13 \pm 0.26 \pm 0.22)\% \notag. \end{equation} Multiplying these values by the branching fraction of the normalization channel, ${\cal B}(Ξ_c^{+} \to Ξ^{-} π^+π^+) = (2.9 \pm 1.3)\%$, the absolute branching fractions are determined to be \begin{equation} {\cal B}(Ξ_c^{+} \to p K_{S}^{0}) = (7.16 \pm 0.46 \pm 0.20 \pm 3.21) \times 10^{-4} \notag, \end{equation} \begin{equation} {\cal B}(Ξ_c^{+} \to Λπ^+) = (4.52 \pm 0.41 \pm 0.26 \pm 2.03) \times 10^{-4} \notag, \end{equation} \begin{equation} {\cal B}(Ξ_c^{+} \to Σ^0 π^+) = (1.20 \pm 0.08 \pm 0.07 \pm 0.54) \times 10^{-3} \notag. \end{equation} The first and second uncertainties above are statistical and systematic, respectively, while the third ones arise from the uncertainty in ${\cal B}(Ξ_c^{+} \to Ξ^{-} π^{+} π^{+})$.

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arXiv2024

Study of the semileptonic decay $D^0\rightarrow \bar{K}^0π^-e^+ν_e$

We report an improved study of the semileptonic decay $D^0 \rightarrow \bar{K}^0π^-e^+ν_{e}$ based on a sample of $7.9~\mathrm{fb}^{-1}$ of $e^+e^-$ annihilation data collected at a center-of-mass energy of 3.773~GeV with the BESIII detector at the BEPCII collider. The branching fraction of this decay is measured to be $\mathcal{B}(D^0\rightarrow \bar{K}^0π^-e^+ν_{e}) = (1.444 \pm 0.022_{\rm stat} \pm 0.024_{\rm syst})\%$, which is the most precise to date, where the first uncertainty is statistical and the second is systematic. Based on investigation of the decay dynamics, we find that the decay is dominated by the $K^{*}(892)^-$ component and present an improved measurement of its branching fraction to be $\mathcal{B}(D^0\rightarrow K^{*}(892)^-e^+ν_e) = (2.039 \pm 0.032_{\rm stat} \pm 0.034_{\rm syst})\%$. We also determine the ratios of the hadronic form factors for the $K^{*}(892)^-e^+ν_e$ decay to be $r_{V} = V(0)/A_1(0) = 1.48 \pm 0.05_{\rm stat} \pm 0.02_{\rm syst}$ and $r_{2} = A_2(0)/A_1(0) = 0.70 \pm 0.04_{\rm stat} \pm 0.02_{\rm syst}$, where $V(0)$ is the vector form factor and $A_{1,2}(0)$ are the axial form factors. In addition, the $\bar{K}^0π^-$ $\mathcal{S}$-wave component is found to account for $(5.87 \pm 0.32_{\rm stat} \pm 0.16_{\rm syst})\%$ of the total decay rate, corresponding to a branching fraction of $\mathcal{B}[D^0\rightarrow (\bar{K}^0π^-)_{S-{\rm wave}}e^+ν_e] = (0.085 \pm 0.005_{\rm stat} \pm 0.003_{\rm syst})\%$.

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arXiv2024

Measurement of the integrated luminosity of the data collected at 3.773 GeV by BESIII from 2021 to 2024

We present a measurement of the integrated luminosity of $e^+e^-$ collision data collected with the BESIII detector at the BEPCII collider at a center-of-mass energy of $E_{\rm cm} = 3.773$~GeV. The integrated luminosities of the data sets taken from December 2021 to June 2022, from November 2022 to June 2023, and from October 2023 to February 2024 are determined to be $4.995 \pm 0.019$~fb$^{-1}$, $8.157 \pm 0.031$~fb$^{-1}$, and $4.191 \pm 0.016$~fb$^{-1}$, respectively, by analyzing large angle Bhabha scattering events. The uncertainties are dominated by systematic effects and the statistical uncertainties are negligible. Our results provide essential input for future analyses and precision measurements.

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arXiv2024

Study of the decay ψ(3686) \to Σ^{0}\barΣ^{0}ϕ

Using $(27.12\pm 0.14)\times 10^{8}$ $ψ(3686)$ events collected with the BESIII detector operating at the BEPCII collider, the decay $ψ(3686)\toΣ^{0}\barΣ^{0}ϕ$ is observed for the first time with a statistical significance of 7.6$σ$. Its branching fraction is measured to be $(2.64 \pm 0.32_{\textrm{stat}} \pm 0.12_{\textrm{sys}}) \times 10^{-6}$, where the first uncertainty is statistical and the second is systematic. In addition, we search for potential intermediate states in the $Σ^{0}ϕ$($\barΣ^{0}ϕ$) invariant mass distribution and a possible threshold enhancement in the $Σ^{0}\barΣ^{0}$ system, but no conclusive evidence of is observed.

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arXiv2024

Measurement of $CP$ asymmetries in $B^0\toη'K^0_s$ decays at Belle II

We describe a measurement of charge-parity ($CP$) violation asymmetries in $B^0\toη'K^0_S$ decays using Belle II data. We consider $η'\toη(\toγγ)π^+π^-$ and $η'\toρ(\toπ^+π^-)γ$ decays. The data were collected at the SuperKEKB asymmetric-energy $e^+e^-$ collider between the years 2019 and 2022, and contain $(387\pm 6) \times 10^6$ bottom-antibottom meson pairs. We reconstruct $829\pm35$ signal decays and extract the $CP$ violating parameters from a fit to the distribution of the proper-decay-time difference between the two $B$ mesons. The measured direct and mixing-induced $CP$ asymmetries are $\text{C}_{η'K^0_S} = -0.19 \pm 0.08 \pm 0.03 $ and $\text{S}_{η'K^0_S} = +0.67 \pm 0.10 \pm 0.04 $, respectively, where the first uncertainties are statistical and the second are systematic. These results are in agreement with current world averages and standard model predictions.

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arXiv2024

Search for lepton number violating decays of $D_s^+\to h^-h^0e^+e^+$

Based on 7.33 fb$^{-1}$ of $e^+e^-$ collision data collected by the BESIII detector operating at the BEPCII collider at center-of-mass energies from 4.128 to 4.226 GeV, a search for the Majorana neutrino $ν_m$ is conducted in the lepton-number-violating decays of $D_s^+\to h^-h^0e^+e^+$. Here, $h^-$ represents a $K^-$ or $π^-$, and $h^0$ represents a $π^0$, $K_S^0$ or $ϕ$. No significant signal is observed, and the upper limits of their branching fractions at the 90\% confidence level are determined to be $\mathcal{B}(D_s^+\to ϕπ^-e^+e^+) < 6.9 \times 10^{-5}$, $\mathcal{B}(D_s^+\to ϕK^-e^+e^+) < 9.9 \times 10^{-5}$, $\mathcal{B}(D_s^+\to K_S^0π^-e^+e^+) < 1.3 \times 10^{-5}$, $\mathcal{B}(D_s^+\to K_S^0K^-e^+e^+) < 2.9 \times 10^{-5}$, $\mathcal{B}(D_s^+\to π^-π^0e^+e^+) < 2.9 \times 10^{-5}$ and $\mathcal{B}(D_s^+\to K^-π^0e^+e^+) < 3.4 \times 10^{-5}$. The Majorana neutrino is searched for with different mass assumptions within the range [0.20, 0.80] GeV$/c^2$ in the decay of $D_s^+\toϕe^+ν_m$ with $ν_m\toπ^-e^+$, and the upper limits of the branching fractions at the 90\% confidence level are at the level of $10^{-5}-10^{-2}$, depending on the mass of the Majorana neutrino.

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arXiv2024

Model-independent determination of the strong-phase difference between $D^0$ and $\bar{D}^0 \to π^+π^-π^+π^-$ decays

Measurements of the strong-phase difference between $D^0$ and $\bar{D}^0\toπ^+π^-π^+π^-$ are performed in bins of phase space. The study exploits a sample of quantum-correlated $D\bar{D}$ mesons collected by the BESIII experiment in $e^+e^-$ collisions at a center-of-mass energy of 3.773~GeV, corresponding to an integrated luminosity of 2.93~fb$^{-1}$. Here, $D$ denotes a neutral charm meson in a superposition of flavor eigenstates. The reported results are valuable for measurements of the $C\!P$-violating phase $γ$ (also denoted $ϕ_3$) in $B^\pm \to DK^\pm$, $D \to π^+π^-π^+π^-$ decays, and the binning schemes are designed to provide good statistical sensitivity to this parameter. The expected uncertainty on $γ$ arising from the precision of the strong-phase measurements, when applied to very large samples of $B$-meson decays, is around $1.5^\circ$ or $2^\circ$, depending on the binning scheme. The binned strong-phase parameters are combined to give a value of $F_+^{4π} = 0.746 \pm 0.010 \pm 0.004$ for the $C\!P$-even fraction of $D^0 \to π^+π^-π^+π^-$ decays, which is around 30\% more precise than the previous best measurement of this quantity.

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arXiv2024

Observation of $D^+\to f_0(500)μ^+ν_μ$ and study of $D^+\to π^+π^-\ell^+ν_\ell$ decay dynamics

Using $2.93~\mathrm{fb}^{-1}$ of $e^+e^-$ collision data collected with the BESIII detector at the center-of-mass energy of 3.773 GeV,we investigate the semileptonic decays $D^+\to π^+π^- \ell^+ν_\ell$ ($\ell=e$ and $μ$). The $D^+\to f_0(500)μ^+ν_μ$ decay is observed for the first time. By analyzing simultaneously the differential decay rates of $D^+\to f_0(500) μ^+ν_μ$ and $D^+\to f_0(500) e^+ν_e$ in different $\ell^+ν_\ell$ four-momentum transfer intervals, the product of the relevant hadronic form factor $f^{f_0}_{+}(0)$ and the magnitude of the $c\to d$ Cabibbo-Kobayashi-Maskawa matrix element $|V_{cd}|$ is determined to be $f_{+}^{f_0} (0)|V_{cd}|=0.143\pm0.014_{\rm stat}\pm0.011_{\rm syst}$ for the first time. With the input of $|V_{cd}|$ from the global fit in the standard model, we determine $f_{+}^{f_0} (0)=0.63\pm0.06_{\rm stat}\pm0.05_{\rm syst}$. The absolute branching fractions of $D^+\to f_0(500)_{(π^+π^-)}μ^+ν_μ$ and $D^+\to ρ^0_{(π^+π^-)} μ^+ν_μ$ are determined as $(0.72\pm0.13_{\rm stat}\pm0.08_{\rm syst})\times10^{-3}$ and $(1.64\pm0.13_{\rm stat}\pm0.10_{\rm syst})\times 10^{-3}$. Combining these results with those of previous BESIII measurements on their semielectronic counterparts from the same data sample, we test lepton flavor universality by measuring the branching fraction ratios ${\mathcal B}_{D^+\to ρ^0 μ^+ν_μ}/{\mathcal B}_{D^+\to ρ^0 e^+ν_e}=0.88\pm0.10$ and ${\mathcal B}_{D^+\to f_0(500) μ^+ν_μ}/{\mathcal B}_{D^+\to f_0(500) e^+ν_e}=1.14\pm0.26$, which are compatible with the standard model expectation.

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arXiv2024

Measurement of Born cross sections of $e^+e^-\toΞ^0\barΞ^0$ and search for charmonium(-like) states at $\sqrt{s}$ = 3.51-4.95 GeV

Using $e^+e^-$ collision data collected by the BESIII detector at BEPCII corresponding to an integrated luminosity of 30 $\rm fb^{-1}$, we measure Born cross sections and effective form factors for the process $e^+e^-\toΞ^0\barΞ^0$ at forty-five center-of-mass energies between 3.51 and 4.95 GeV. The dressed cross section is fitted, assuming a power-law function plus a charmonium(-like) state, i.e., $ψ(3770)$, $ψ(4040)$, $ψ(4160)$, $ψ(4230)$, $ψ(4360)$, $ψ(4415)$ or $ψ(4660)$. No significant charmonium(-like) state decaying into $Ξ^0\barΞ^0$ is observed. Upper limits at the 90% confidence level on the product of the branching fraction and the electronic partial width are provided for each decay. In addition, ratios of the Born cross sections and the effective form factors for $e^+e^-\toΞ^0\barΞ^0$ and $e^+e^-\toΞ^-\barΞ^+$ are also presented to test isospin symmetry and the vector meson dominance model.

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arXiv2024

Search for $η_c(2S)\to p\bar{p}$ and branching fraction measurements of $χ_{cJ} \to p\bar{p}$ via $ψ(2S)$ radiative decays

Using $(27.12\pm0.14) \times 10^{8}$ $ψ(2S)$ events collected by the BESIII detector operating at BEPCII, we search for the decay $η_c(2S)\to p\bar{p}$ via the process $ψ(2S)\to γη_c(2S)$, and only find a signal with a significance of $1.7\,σ$. The upper limit of the product branching fraction at the 90% confidence level is determined to be $\mathcal{B}(ψ(2S)\to γη_c(2S))\times \mathcal{B}(η_c(2S)\to p\bar{p})<2.4\times 10^{-7}$. The branching fractions of $χ_{cJ}\to p\bar{p}~(J=0,1,2)$ are also measured to be $\mathcal{B}(χ_{c0}\to p\bar{p})=(2.51\pm0.02\pm0.08)\times 10^{-4}$, $\mathcal{B}(χ_{c1}\to p\bar{p})=(8.16\pm0.09\pm0.25)\times 10^{-4}$, and $\mathcal{B}(χ_{c2}\to p\bar{p})=(8.33\pm0.09\pm0.22)\times 10^{-4}$, where the first uncertainty is statistical and the second systematic.

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arXiv2024

Measurement of the branching fractions of the decays $Λ_{c}^{+}\rightarrowΛK_{S}^{0}K^{+}$, $Λ_{c}^{+}\rightarrowΛK_{S}^{0}π^{+}$ and $Λ_{c}^{+}\rightarrowΛK^{*+}$

Studies are performed of the Cabibbo-favored decay $Λ_{c}^{+}\toΛK_{S}^{0}K^+$ and the singly Cabibbo-suppressed decay $Λ_{c}^{+}\toΛK_{S}^{0}π^+$, based on a sample of $e^{+}e^{-}$ collision data, corresponding to an integrated luminosity of 4.5 fb$^{-1}$, accumulated at center-of-mass energies between $4599.53$ MeV and $4698.82$ MeV with the BESIII detector. The decay $Λ_{c}^{+}\toΛK_{S}^{0}π^+$ is observed for the first time. The branching fractions of $Λ_{c}^{+}\toΛK_{S}^{0}K^+$ and $Λ_{c}^{+}\toΛK_{S}^{0}π^+$ are measured to be $(3.04\pm0.30\pm0.16)\times 10^{-3}$ and $(1.73\pm0.27\pm0.10)\times 10^{-3}$, respectively, where the first uncertainties are statistical and the second are systematic. These results correspond to the most precise measurement of these quantities for both decays. Evidence of a $K^{*+}$ contribution in the $Λ_{c}^{+}\toΛK_{S}^{0}π^+$ decay is found with a statistical significance of $4.7σ$. The branching fraction of $Λ_{c}^{+}\toΛK^{*+}$ is calculated under three possible interference scenarios.

hep-ex↗

arXiv2024

Observation of $χ_{c0}\toΣ^{+}\barΣ^{-}η$ and evidence for $χ_{c1,2}\toΣ^{+}\barΣ^{-}η$

Using $(27.12\pm 0.14)\times10^{8}$ $ψ(3686)$ events collected with the BESIII detector, the decay $χ_{c0}\toΣ^{+}\barΣ^{-}η$ is observed for the first time with a statistical significance of $7.0σ$, and evidence for $χ_{c1}\toΣ^{+}\barΣ^{-}η$ and $χ_{c2}\toΣ^{+}\barΣ^{-}η$ is found with statistical significances of $4.3σ$ and $4.6σ$, respectively. The branching fractions are determined to be $\mathcal{B}(χ_{c0}\toΣ^{+}\barΣ^{-}η)=({1.26 \pm 0.20 \pm 0.13}) \times 10^{-4}, ~\mathcal{B}(χ_{c1}\toΣ^{+}\barΣ^{-}η)=({5.10 \pm 1.21 \pm 0.67}) \times 10^{-5}$, and $\mathcal{B}(χ_{c2}\toΣ^{+}\barΣ^{-}η)=({5.46 \pm 1.18 \pm 0.50}) \times 10^{-5}$, where the first uncertainties are statistical, and the second ones are systematic.

hep-ex↗