arXiv subjects

H. -R. Bao

Publications and source records attributed to H. -R. Bao.

At least 253 records · Page 14Linked to original sources

arXiv2024

Measurements of Born Cross Sections for $e^+e^-\to Λ_{c}^+ \barΛ_{c}(2595)^- + {\rm c.c.}$ and $e^+e^-\to Λ_{c}^+ \barΛ_{c}(2625)^- + {\rm c.c.}$ at $\sqrt{s}=$4918.0 and 4950.9 MeV

Using $e^+e^-$ collision data collected with the BESIII detector operating at the BEPCII collider, the Born cross sections of $e^+e^-\to Λ_{c}^+ \barΛ_{c}(2595)^- + \rm{c.c.}$ and $e^+e^-\to Λ_{c}^+ \barΛ_{c}(2625)^- + \rm{c.c.}$ are measured for the first time at center-of-mass energies of $\sqrt{s}=4918.0$ and 4950.9 MeV. Non-zero cross sections are observed very close to the production threshold. The measured Born cross sections of $e^+e^-\to Λ_{c}^+ \barΛ_{c}(2625)^- + \rm{c.c.}$ are about $2\sim3$ times greater than those of $e^+e^-\to Λ_{c}^+ \barΛ_{c}(2595)^- + \rm{c.c.}$, thereby indicating that the exotic structure potentially exists in the excited charmed baryons. The Born cross sections are $15.6\pm3.1\pm0.9$ pb and $29.4\pm3.7\pm2.7$ pb for $e^+e^-\to Λ_{c}^+ \barΛ_{c}(2595)^- + \rm{c.c.}$, and are $43.4\pm4.0\pm4.1$ pb and $76.8\pm6.5\pm4.2$ pb for $e^+e^-\to Λ_{c}^+ \barΛ_{c}(2625)^- +\rm{c.c.}$ at $\sqrt s=4918.0$ and 4950.9 MeV, respectively. Based on the polar angle distributions of the $\barΛ_{c}(2625)^-$ and $Λ_{c}(2625)^+$, the form-factor ratios $\sqrt{|G_{E}|^2 + 3|G_{M}|^2}/|G_{C}|$ are determined for $e^+e^-\to Λ_{c}^+ \barΛ_{c}(2625)^- + \rm{c.c.}$ for the first time, which are $5.95\pm4.07\pm0.15$ and $0.94\pm0.32\pm0.02$ at $\sqrt s=4918.0$ and 4950.9 MeV, respectively. All of these first uncertainties are statistical and second systematic.

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arXiv2024

Measurement of Born cross section of $e^{+}e^{-}\rightarrowΣ^{+}\barΣ^{-}$ at center-of-mass energies between 3.510 and 4.951 GeV

Using 24.1 fb$^{-1}$ of $e^{+}e^{-}$ collision data collected with the BESIII detector at the BEPCII collider, the Born cross sections and effective form factors of the $e^{+}e^{-}\rightarrowΣ^{+}\barΣ^{-}$ reaction are measured. The measurements are performed at center-of-mass energies ranging from 3.510 to 4.951 GeV. No significant evidence for the decay of the charmonium(-like) states, $ψ(3770)$, $ψ(4040)$, $ψ(4160)$, $Y(4230)$, $Y(4360)$, $ψ(4415)$, and $Y(4660)$, into a $Σ^{+}\barΣ^{-}$ final state is observed. Consequently, upper limits for the products of the branching fractions and the electronic partial widths at the 90% confidence level are reported for these decays.

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arXiv2024

Determination of spin-parity quantum numbers of X(2370) as $0^{-+}$ from $J/ψ\rightarrowγK^{0}_{S}K^{0}_{S}η^{\prime}$

Based on $(10087\pm44)\times10^{6}$ $J/ψ$ events collected with the BESIII detector, a partial wave analysis of the decay $J/ψ\rightarrowγK^{0}_{S}K^{0}_{S}η^{\prime}$ is performed. The mass and width of the $X(2370)$ are measured to be $2395 \pm 11 ({\rm stat})^{+26}_{-94}({\rm syst})\ \mathrm{MeV}/c^{2}$ and $188^{+18}_{-17}({\rm stat})^{+124}_{-33}({\rm syst})~\mathrm{MeV}$, respectively. The corresponding product branching fraction is $\mathcal{B}[J/ψ\rightarrowγX(2370)] \times \mathcal{B}[X(2370) \rightarrow f_{0}(980)η^{\prime}] \times \mathcal{B}[f_{0}(980) \rightarrow K^{0}_{S}K^{0}_{S}] = \left( 1.31 \pm 0.22 ({\rm stat})^{+2.85}_{-0.84}({\rm syst}) \right) \times 10^{-5}$. The statistical significance of the $X(2370)$ is greater than $11.7σ$ and the spin-parity is determined to be $0^{-+}$ for the first time. The measured mass and spin-parity of the $X(2370)$ are consistent with the predictions of the lightest pseudoscalar glueball.

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arXiv2024

Observation of $ψ(3686) \to Ω^- K^+ \barΞ^0 $+c.c

Using $(27.12 \pm 0.14) \times 10^{8}$ $ψ(3686)$ events collected with the BESIII detector at BEPCII, the decay of $ψ(3686) \to Ω^- K^+ \barΞ^0 +c.c.$ is observed for the first time. The branching fraction of this decay is measured to be $\mathcal{B}_{ψ(3686) \to Ω^- K^+ \barΞ^0 +c.c.}=(2.78 \pm 0.40 \pm 0.18 ) \times 10^{-6}$, where the first uncertainty is statistical and the second is systematic. Possible baryon excited states are searched for in this decay, but no evident intermediate state is observed with the current sample size.

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arXiv2024

Search for $ΔS=2$ nonleptonic hyperon decays $Ω^-\toΣ^{0}π^{-}$ and $Ω^-\to nK^{-}$

Using $(27.12 \pm 0.14) \times 10^{8}$ $ψ(3686)$ events collected by the BESIII detector at the center-of-mass energy of $\sqrt{s} = 3.686$ GeV, we search for the first time for two nonleptonic hyperon decays that change strangeness by two units, $Ω^-\toΣ^{0}π^-$ and $Ω^-\to nK^{-}$. No significant signal is observed. The upper limits on their decay branching fractions are determined to be $\mathcal{B}(Ω^-\toΣ^{0}π^-) < 5.4\times 10^{-4}$ and $\mathcal{B}(Ω^-\to nK^{-}) < 2.4\times 10^{-4}$ at the $90\%$ confidence level.

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arXiv2024

Observation of $D \to a_{0}(980)π$ in the decays $D^{0} \rightarrow π^{+}π^{-}η$ and $D^{+} \rightarrow π^{+}π^{0}η$

We report the first amplitude analysis of the decays $D^{0} \to π^{+} π^{-} η$ and $D^{+} \rightarrow π^{+}π^{0}η$ using a data sample taken with the BESIII detector at the center-of-mass energy of 3.773 GeV, corresponding to an integrated luminosity of 7.9 ${\rm fb}^{-1}$. The contribution from the process $D^{0(+)} \to a_{0}(980)^{+} π^{-(0)}$ is significantly larger than the $D^{0(+)} \to a_{0}(980)^{-(0)} π^{+}$ contribution. The ratios $\mathcal{B}(D^{0} \rightarrow a_{0}(980)^{+}π^{-})/\mathcal{B}(D^{0} \rightarrow a_{0}(980)^{-}π^{+})$ and $\mathcal{B}(D^{+} \rightarrow a_{0}(980)^{+}π^{0})/\mathcal{B}(D^{+} \rightarrow a_{0}(980)^{0}π^{+})$ are measured to be $7.5^{+2.5}_{-0.8\,\mathrm{stat.}}\pm1.7_{\mathrm{syst.}}$ and $2.6\pm0.6_{\mathrm{stat.}}\pm0.3_{\mathrm{syst.}}$, respectively. The measured $D^{0}$ ratio disagrees with the theoretical predictions by orders of magnitudes, thus implying a substantial contribution from final-state interactions.

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arXiv2024

Measurement of the Born cross section for $e^{+}e^{-}\to ηh_c $ at center-of-mass energies between 4.1 and 4.6\,GeV

We measure the Born cross section for the reaction $e^{+}e^{-} \rightarrow ηh_c$ from $\sqrt{s} = 4.129$ to $4.600$~GeV using data sets collected by the BESIII detector running at the BEPCII collider. A resonant structure in the cross section line shape near 4.200~GeV is observed with a statistical significance of 7$σ$. The parameters of this resonance are measured to be \MeasMass\ and \MeasWidth, where the first uncertainties are statistical and the second systematic.

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arXiv2024

Search for the Rare Decays $D_s^+\to h^+(h^{0})e^+e^-$

Using 7.33~fb$^{-1}$ of $e^{+}e^{-}$ collision data collected by the BESIII detector at center-of-mass energies in the range of $\sqrt{s}=4.128 - 4.226$~GeV, we search for the rare decays $D_{s}^+\to h^+(h^{0})e^{+}e^{-}$, where $h$ represents a kaon or pion. By requiring the $e^{+}e^{-}$ invariant mass to be consistent with a $ϕ(1020)$, $0.98<M(e^{+}e^{-})<1.04$ ~GeV/$c^2$, the decay $D_s^+\toπ^+ϕ,ϕ\to e^{+}e^{-}$ is observed with a statistical significance of 7.8$σ$, and evidence for the decay $D_s^+\toρ^+ϕ,ϕ\to e^{+}e^{-}$ is found for the first time with a statistical significance of 4.4$σ$. The decay branching fractions are measured to be $\mathcal{B}(D_s^+\toπ^+ϕ, ϕ\to e^{+}e^{-} )=(1.17^{+0.23}_{-0.21}\pm0.03)\times 10^{-5}$, and $\mathcal{B}(D_s^+\toρ^+ϕ, ϕ\to e^{+}e^{-} )=(2.44^{+0.67}_{-0.62}\pm 0.16)\times 10^{-5}$, where the first uncertainties are statistical and the second systematic. No significant signal for the three four-body decays of $D_{s}^{+}\to π^{+}π^{0}e^{+}e^{-},\ D_{s}^{+}\to K^{+}π^{0}e^{+}e^{-}$, and $D_{s}^{+}\to K_{S}^{0}π^{+}e^{+}e^{-}$ is observed. For $D_{s}^{+}\to π^{+}π^{0}e^{+}e^{-}$, the $ϕ$ mass region is vetoed to minimize the long-distance effects. The 90$\%$ confidence level upper limits set on the branching fractions of these decays are in the range of $(7.0-8.1)\times 10^{-5}$.

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arXiv2024

Improved measurements of the Dalitz decays $η/η'\rightarrowγe^{+}e^{-}$

Based on a data sample of 10 billion $J/ψ$ events collected with the BESIII detector, improved measurements of the Dalitz decays $η/η'\rightarrowγe^+e^-$ are performed, where the $η$ and $η'$ are produced through the radiative decays $J/ψ\rightarrowγη/η'$. The branching fractions of $η\rightarrowγe^+e^-$ and $η'\rightarrowγe^+e^-$ are measured to be $(7.07 \pm 0.05 \pm 0.23)\times10^{-3}$ and $(4.83\pm0.07\pm0.14)\times10^{-4}$, respectively. Within the single pole model, the parameter of electromagnetic transition form factor for $η\rightarrowγe^+e^-$ is determined to be $Λ_η=(0.749 \pm 0.027 \pm 0.007)~ {\rm GeV}/c^{2}$. Within the multi-pole model, we extract the electromagnetic transition form factors for $η'\rightarrowγe^+e^-$ to be $Λ_{η'} = (0.802 \pm 0.007\pm 0.008)~ {\rm GeV}/c^{2}$ and $γ_{η'} = (0.113\pm0.010\pm0.002)~ {\rm GeV}/c^{2}$. The results are consistent with both theoretical predictions and previous measurements. The characteristic sizes of the interaction regions for the $η$ and $η'$ are calculated to be $(0.645 \pm 0.023 \pm 0.007 )~ {\rm fm}$ and $(0.596 \pm 0.005 \pm 0.006)~ {\rm fm}$, respectively. In addition, we search for the dark photon in $η/η^\prime\rightarrowγe^{+}e^{-}$, and the upper limits of the branching fractions as a function of the dark photon are given at 90\% confidence level.

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arXiv2024

Evidence of the $h_c\to K_S^0 K^+π^-+c.c.$ decay

Based on $(2.712\pm0.014)\times10^9$ $ψ(3686)$ events collected by the BESIII collaboration, evidence of the hadronic decay $h_c\to K_S^0K^+π^-+c.c.$ is found with a significance of $4.3σ$ in the $ψ(3686)\toπ^0 h_c$ process. The branching fraction of $h_c\to K_S^0 K^+π^- +c.c.$ is measured to be $(7.3\pm0.8\pm1.8)\times10^{-4}$, where the first and second uncertainties are statistical and systematic, respectively. Combining with the exclusive decay width of $η_c\to K\bar{K}π$, our result indicates inconsistencies with both pQCD and NRQCD predictions.

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arXiv2024

Amplitude Analysis of the Decays $D^0\toπ^+π^-π^+π^-$ and $π^+π^-π^0π^0$

Using $e^+e^-$ annihilation data corresponding to an integrated luminosity of 2.93 $\rm fb^{-1}$ taken at the center-of-mass energy $\sqrt{s}=3.773$~GeV with the BESIII detector, a joint amplitude analysis is performed on the decays $D^0\toπ^+π^-π^+π^-$ and $D^0\toπ^+π^-π^0π^0$(non-$η$). The fit fractions of individual components are obtained, and large interferences among the dominant components of $D^{0}\to a_{1}(1260)π$, $D^{0}\toπ(1300)π$, $D^{0}\toρ(770)ρ(770)$ and $D^{0}\to2(ππ)_{S}$ are found in both channels. With the obtained amplitude model, the $CP$-even fractions of $D^0\to π^+π^-π^+π^-$ and $D^0\toπ^+π^-π^0π^0$(non-$η$) are determined to be $(75.2\pm1.1_{\rm stat.}\pm1.5_{\rm syst.})\%$ and $(68.9\pm1.5_{\rm stat.}\pm 2.4_{\rm syst.})\%$, respectively. The branching fractions of $D^0\to π^+π^-π^+π^-$ and $D^0\toπ^+π^-π^0π^0$(non-$η$) are measured to be $(0.688\pm0.010_{\rm stat.}\pm 0.010_{\rm syst.})\%$ and $(0.951\pm0.025_{\rm stat.}\pm 0.021_{\rm syst.})\%$, respectively. The amplitude analysis provides an important model for binning strategy in the measurements of the strong phase parameters of $D^0 \to 4π$ when used to determine the CKM angle $γ(ϕ_{3})$ via the $B^{-}\to D K^{-}$ decay.

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arXiv2024

First observation of the decay $Λ^+_c\to nK^{0}_{S}π^+π^0$

Based on 4.5 fb$^{-1}$ of $e^{+}e^{-}$ collision data accumulated at center-of-mass energies between $4599.53$ MeV and $4698.82$ MeV with the BESIII detector, the decay $Λ_{c}^{+}\to nK_{S}^{0}π^+π^0$ is observed for the first time with a significance of $9.2σ$. The branching fraction is measured to be $(0.85\pm0.13\pm0.03)\%$, where the first uncertainty is statistical and the second systematic, which differs from the theoretical prediction based on isospin by 4.4$σ$. This indicates that there may be resonant contributions or some unknown dynamics in this decay.

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arXiv2024

Observation of structures in the processes $e^+e^-\rightarrowωχ_{c1}$ and $ωχ_{c2}$

We present measurements of the Born cross sections for the processes $e^+e^-\rightarrowωχ_{c1}$ and $ωχ_{c2}$ at center-of-mass energies $\sqrt{s}$ from 4.308 to 4.951 GeV. The measurements are performed with data samples corresponding to an integrated luminosity of 11.0 $\rm{fb}^{-1}$ collected with the BESIII detector operating at the BEPCII storage ring. Assuming the $e^+e^-\rightarrowωχ_{c2}$ signals come from a single resonance, the mass and width are determined to be $M=(4413.6\pm9.0\pm0.8)$ MeV/$c^2$ and $Γ=(110.5\pm15.0\pm2.9)$ MeV, respectively, which is consistent with the parameters of the well-established resonance $ψ(4415)$. In addition, we also use one single resonance to describe the $e^+e^-\rightarrowωχ_{c1}$ lineshape, and determine the mass and width to be $M=(4544.2\pm18.7\pm1.7)$ MeV/$c^2$ and $Γ=(116.1\pm33.5\pm1.7)$ MeV, respectively. The structure of this lineshape, observed for the first time, requires further understanding.

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arXiv2024

Precise measurement of the $e^+e^-\to D_s^+D_s^-$ cross sections at center-of-mass energies from threshold to 4.95 GeV

Using the $e^+e^-$ collision data collected with the BESIII detector operating at the BEPCII collider, at center-of-mass energies from the threshold to $4.95$~GeV, we present precise measurements of the cross sections for the process $e^+e^-\to D_s^+D_s^-$ using a single tag method. The resulting cross section lineshape exhibits several new structures, thereby offering an input for coupled channel analysis and model tests, which are critical to understand vector charmonium-like states with masses between 4 and 5~GeV.

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arXiv2024

Observation of the decay $h_{c}\to3(π^{+}π^{-})π^{0}$

Based on $(2712.4\pm14.1)\times10^{6}$ $ψ(3686)$ events collected with the BESIII detector, we study the decays $h_{c}\to3(π^{+}π^{-})π^{0}$, $h_{c}\to2(π^{+}π^{-})ω$, $h_{c}\to2(π^{+}π^{-})π^{0}η$, $h_{c}\to2(π^{+}π^{-})η$, and $h_{c}\to p\bar{p}$ via $ψ(3686)\toπ^{0}h_{c}$. The decay channel $h_{c}\to3(π^{+}π^{-})π^{0}$ is observed for the first time, and its branching fraction is determined to be $\left( {9.28\pm 1.14 \pm 0.77} \right) \times {10^{ - 3}}$, where the first uncertainty is statistical and the second is systematic. In addition, first evidence is found for the modes $h_{c} \to 2(π^{+}π^{-})π^{0}η$ and $h_{c}\to2(π^{+}π^{-})ω$ with significances of 4.8$σ$ and 4.7$σ$, and their branching fractions are determined to be $(7.55\pm1.51\pm0.77)\times10^{-3}$ and $\left( {4.00 \pm 0.86 \pm 0.35}\right) \times {10^{ - 3}}$, respectively. No significant signals of $h_c\to 2(π^+π^-)η$ and $h_{c}\to p\bar{p}$ are observed, and the upper limits of the branching fractions of these decays are determined to be $<6.19\times10^{-4}$ and $<4.40\times10^{-5}$ at the 90% confidence level, respectively.

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arXiv2024

Observation of $ψ(3686)\to 3ϕ$

Using $(2.712\pm0.014)\times 10^9$ $ψ(3686)$ events collected by the BESIII detector operating at the BEPCII collider, we report the first observation of $ψ(3686)\to 3ϕ$ decay with a significance larger than 10$σ$. The branching fraction of this decay is determined to be $(1.46\pm0.05\pm0.17)\times10^{-5}$, where the first uncertainty is statistical and the second is systematic. No significant structure is observed in the $ϕϕ$ invariant mass spectra.

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arXiv2024

First observation of $Λ_c^+\rightarrowΛK^+π^0$ and evidence of $Λ_c^+\rightarrowΛK^+π^+π^-$

We present the first observation of the singly Cabibbo-suppressed decay $Λ_c^+ \rightarrow ΛK^+π^0$ with a significance of $5.7σ$ and the first evidence of $Λ_c^+ \rightarrow ΛK^+π^+π^-$ decay with a significance of $3.1σ$, based on $e^+e^-$ annihilation data recorded by the BESIII detector at the BEPCII collider. The data correspond to an integrated luminosity of $6.4~{\rm fb^{-1}}$, in the center-of-mass energy range from $4.600~{\rm GeV}$ to $4.950~{\rm GeV}$. We determine the branching fractions of $Λ_c^+ \rightarrow ΛK^+π^0$ and $Λ_c^+ \rightarrow ΛK^+π^+π^-$ relative to their Cabibbo-favored counterparts to be $\frac{\mathcal{B}(Λ_c^+ \rightarrow ΛK^+π^0)}{\mathcal{B}(Λ_c^+ \rightarrow Λπ^+π^0)} = (2.09\pm0.39_{\mathrm{stat.}}\pm0.07_{\mathrm{syst.}}) \times 10^{-2}$ and $\frac{\mathcal{B}(Λ_c^+ \rightarrow ΛK^+π^+π^-)}{\mathcal{B}(Λ_c^+ \rightarrow Λπ^+π^+π^-)} = (1.13\pm0.41_{\mathrm{stat.}}\pm0.06_{\mathrm{syst.}}) \times 10^{-2}$, respectively. Moreover, by combining our measured result with the world average of $\mathcal{B}(Λ^+_c\to Λπ^+π^0)$, we obtain the branching fraction $\mathcal{B}(Λ_c^+ \to ΛK^+π^0) = (1.49\pm0.27_{\mathrm{stat.}}\pm0.05_{\mathrm{syst.}}\pm0.08_{\mathrm{ref.}}) \times 10^{-3}$. This result significantly departs from theoretical predictions based on quark $SU(3)$ flavor symmetry, which is underpinned by the presumption of meson pair $S$-wave amplitude dominance.

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arXiv2024

Search for a muonphilic scalar $X_{0}$ or vector $X_{1}$ via $J/ψ\toμ^+μ^-+\rm{invisible}$ decays at BESII

A light scalar $X_{0}$ or vector $X_{1}$ particles have been introduced as a possible explanation for the $(g-2)_μ$ anomaly and dark matter phenomena. Using $(8.998\pm 0.039)\times10^9$ $\jpsi $ events collected by the BESIII detector, we search for a light muon philic scalar $X_{0}$ or vector $X_{1}$ in the processes $J/ψ\toμ^+μ^- X_{0,1}$ with $X_{0,1}$ invisible decays. No obvious signal is found, and the upper limits on the coupling $g_{0,1}'$ between the muon and the $X_{0,1}$ particles are set to be between $1.1\times10^{-3}$ and $1.0\times10^{-2}$ for the $X_{0,1}$ mass in the range of $1<M(X_{0,1})<1000$ MeV$/c^2$ at 90$\%$ confidence level.

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