arXiv subjects

R. B. de Boer

Publications and source records attributed to R. B. de Boer.

At least 19 recordsLinked to original sources

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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arXiv2021

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

We report an amplitude analysis and branching fraction measurement of $D_{s}^{+} \rightarrow K^{+}K^{-}π^{+}$ decay using a data sample of 3.19 $\rm fb^{-1}$ recorded with BESIII detector at a center-of-mass energy of 4.178 GeV. We perform a model-independent partial wave analysis in the low $K^{+}K^{-}$ mass region to determine the $K^{+}K^{-}$ S-wave lineshape, followed by an amplitude analysis of our very pure high-statistics sample. The amplitude analysis provides an accurate determination of the detection efficiency allowing us to measure the branching fraction ${\cal B}(D_{s}^{+} \rightarrow K^{+}K^{-}π^{+}) = (5.47\pm0.08_{\rm stat}\pm0.13_{\rm sys})\%$.

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arXiv2021

Cross section measurement of $e^{+}e^{-} \to K_{S}^{0}K_{L}^{0}$ at $\sqrt{s}=2.00-3.08~{\rm GeV}$

The cross sections of the process $e^{+}e^{-} \to K_{S}^{0}K_{L}^{0}$ are measured at fifteen center-of-mass energies $\sqrt{s}$ from $2.00$ to $3.08~{\rm GeV}$ with the BESIII detector at the Beijing Electron Positron Collider (BEPCII). The results are found to be consistent with those obtained by BaBar. A resonant structure around $2.2~{\rm GeV}$ is observed, with a mass and width of $2273.7 \pm 5.7 \pm 19.3~{\rm MeV}/c^2$ and $86 \pm 44 \pm 51~{\rm MeV}$, respectively, where the first uncertainties are statistical and the second ones are systematic. The product of its radiative width ($Γ_{e^+e^-}$) with its branching fraction to $K_{S}^{0}K_{L}^{0}$ ($Br_{K_{S}^{0}K_{L}^{0}}$) is $0.9 \pm 0.6 \pm 0.7~{\rm eV}$.

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arXiv2021

Measurement of the absolute branching fraction of $Λ_c^+\to p K^0_{\mathrm{S}}η$ decays

Based on 586 $\rm{pb^{-1}}$ of $e^+e^-$ annihilation data collected at a center-of-mass energy of $\sqrt{s}=4.6~\rm{GeV}$ with the BESIII detector at the BEPCII collider, the absolute branching fraction of $Λ_c^+ \to p K^0_{\mathrm{S}}η$ decays is measured for the first time to be $\mathcal{B}(Λ_c^+ \to p K^0_{\mathrm{S}}η) = (0.414 \pm 0.084 \pm 0.028)\%$, where the first uncertainty is statistical and the second is systematic. The result is compatible with a previous CLEO result on the relative branching fraction $\frac{\mathcal{B}(Λ_c^+ \to p K^0_{\mathrm{S}}η)}{\mathcal{B}(Λ_c^+ \to p K^-π^+)}$, and consistent with theoretical predictions of SU(3) flavor symmetry.

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arXiv2021

Determination of the $Λ_c^+$ spin via the reaction $e^+e^-\toΛ_c^+\barΛ_c^-$

We report on a comparison of two possible $Λ_c^+$ spin hypotheses, $J=\frac{1}{2}$ and $\frac{3}{2}$, via the process $e^+e^-\toΛ_c^+\barΛ_c^-$, using the angular distributions of $Λ_c^+$ decays into $pK_S^0$, $Λπ^+$, $Σ^0π^+$, and $Σ^+π^0$. The data were recorded at $\sqrt s = 4.6$ GeV with the BESIII detector and correspond to an integrated luminosity of 587 pb$^{-1}$. The $Λ_c^+$ spin is determined to be $J=\frac{1}{2}$, with this value favored over the $\frac{3}{2}$ hypothesis with a significance corresponding to more than 6 Gaussian standard deviations.

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arXiv2021

Observation of a near-threshold structure in the $K^+$ recoil-mass spectra in $e^+e^-\to K^+ (D_s^- D^{0} + D^{-}_s D^0)$

We report a study of the processes of $e^+e^-\to K^+ (D_s^- D^{*0} + D^{*-}_s D^0)$ based on $e^+e^-$ annihilation samples collected with the BESIII detector operating at BEPCII at five center-of-mass energies ranging from 4.628 to 4.698 GeV with a total integrated luminosity of 3.7 fb$^{-1}$. An excess over the known contributions of the conventional charmed mesons is observed near the $D_s^- D^{*0}$ and $D^{*-}_s D^0$ mass thresholds in the $K^{+}$ recoil-mass spectrum for events collected at $\sqrt{s}=4.681$ GeV. The structure matches a mass-dependent-width Breit-Wigner line shape, whose pole mass and width are determined as $(3982.5^{+1.8}_{-2.6}\pm2.1)$ MeV/$c^2$ and $(12.8^{+5.3}_{-4.4}\pm3.0)$ MeV, respectively. The first uncertainties are statistical and the second are systematic. The significance of the resonance hypothesis is estimated to be 5.3 $σ$ over the contributions only from the conventional charmed mesons. This is the first candidate of the charged hidden-charm tetraquark with strangeness, decaying into $D_s^- D^{*0}$ and $D^{*-}_s D^0$. However, the properties of the excess need further exploration with more statistics.

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arXiv2021

Model independent determination of the spin of the $Ω^{-}$ and its polarization alignment in $ψ(3686)\rightarrowΩ^{-}\barΩ^{+}$

We present an analysis of the process $ψ(3686) \to Ω^- \barΩ^+$ ($Ω^-\to K^-Λ$, $\barΩ^+\to K^+\barΛ$, $Λ\to pπ^-$, $\barΛ\to \bar{p}π^+$) based on a data set of $448\times 10^6$ $ψ(3686)$ decays collected with the BESIII detector at the BEPCII electron-positron collider. The helicity amplitudes for the process $ψ(3686) \to Ω^- \barΩ^+$ and the decay parameters of the subsequent decay $Ω^-\to K^-Λ$ $(\barΩ^+\to K^+\barΛ)$ are measured for the first time by a fit to the angular distribution of the complete decay chain. The branching fraction of $ψ(3686) \to Ω^- \barΩ^+$ is measured to be $(5.82\pm 0.12\pm 0.24)\times 10^{-5}$, with an improved precision compared to previous measurements.

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arXiv2020

Observation of di-structures in $e^+e^-\rightarrow{J}/ψ{\rm X}$ at center-of-mass energies around 3.773 GeV

We report a measurement of the observed cross sections of the inclusive $J/ψ$ production in $e^+e^-\rightarrow {J}/ψ{\rm X}$ based on 3.21 fb$^{-1}$ of data accumulated at energies from 3.645 to 3.891 GeV with the BESIII detector operated at the BEPCII collider. The energy-dependent lineshape obtained from the measured cross sections cannot be well described by two Breit-Wigner (BW) amplitudes of the expected decays $ψ(3686)\rightarrow {J}/ψ{\rm X}$ and $ψ(3770)\rightarrow {J}/ψ{\rm X}$. Instead it can be better described with three BW amplitudes of the decays $ψ(3686)\rightarrow {J}/ψ{\rm X}$, $R(3760)\rightarrow {J}/ψ{\rm X}$ and $R(3790)\rightarrow {J}/ψ{\rm X}$ with two distinct structures referred to as $R(3760)$ and $R(3790)$. Under this assumption, we extracted their masses, total widths, and the product of the leptonic width and decay branching fractions to be $M_{R(3760)}= {3761.7\pm 2.2 \pm 1.2}$ MeV/$c^2$, $Γ^{\rm tot}_{R(3760)}= {6.7\pm 11.1 \pm 1.1}$ MeV, $Γ^{ee}_{R(3760)}\mathcal B[R(3760)\rightarrow {J}/ψ{\rm X}]=(4.0\pm 4.3\pm 1.2)$ eV, $M_{R(3790)} = {3784.7\pm 5.7 \pm 1.6}$ MeV/$c^2$, $Γ^{\rm tot}_{R(3790)} = {31.6 \pm 11.9 \pm 3.2}$ MeV, $Γ^{ee}_{R(3790)}\mathcal B[R(3790)\rightarrow {J}/ψ{\rm X}]=(18.1\pm 10.3\pm 4.7)$ eV, where the first uncertainties are statistical and second systematic.

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arXiv2020

Measurement of the absolute branching fraction of the inclusive decay $Λ_c^+ \to K_S^0X$

We report the first measurement of the absolute branching fraction of the inclusive decay $Λ_c^+ \to K_S^0X$. The analysis is performed using an $e^+e^-$ collision data sample corresponding to an integrated luminosity of 567 pb$^{-1}$ taken at $\sqrt{s}$ = 4.6 GeV with the BESIII detector. Using eleven Cabibbo-favored $\barΛ_c^-$ decay modes and the double-tag technique, this absolute branching fraction is measured to be $\mathcal{B}(Λ_c^+ \to K_S^0X)=(9.9\pm0.6\pm0.4)\%$, where the first uncertainty is statistical and the second systematic. The relative deviation between the branching fractions for the inclusive decay and the observed exclusive decays is $(18.7\pm8.3)\%$, which indicates that there may be some unobserved decay modes with a neutron or excited baryons in the final state.

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arXiv2020

Study of BESIII Trigger Efficiencies with the 2018 $J/ψ$ Data

Using a dedicated data sample taken in 2018 on the $J/ψ$ peak, we perform a detailed study of the trigger efficiencies of the BESIII detector. The efficiencies are determined from three representative physics processes, namely Bhabha-scattering, dimuon production and generic hadronic events with charged particles. The combined efficiency of all active triggers approaches $100\%$ in most cases with uncertainties small enough as not to affect most physics analyses.

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arXiv2020

Precise Measurements of Branching Fractions for $D_s^+$ Meson Decays to Two Pseudoscalar Mesons

We measure the branching fractions for seven $D_{s}^{+}$ two-body decays to pseudo-scalar mesons, by analyzing data collected at $\sqrt{s}=4.178\sim4.226$ GeV with the BESIII detector at the BEPCII collider. The branching fractions are determined to be $\mathcal{B}(D_s^+\to K^+η^{\prime})=(2.68\pm0.17\pm0.17\pm0.08)\times10^{-3}$, $\mathcal{B}(D_s^+\toη^{\prime}π^+)=(37.8\pm0.4\pm2.1\pm1.2)\times10^{-3}$, $\mathcal{B}(D_s^+\to K^+η)=(1.62\pm0.10\pm0.03\pm0.05)\times10^{-3}$, $\mathcal{B}(D_s^+\toηπ^+)=(17.41\pm0.18\pm0.27\pm0.54)\times10^{-3}$, $\mathcal{B}(D_s^+\to K^+K_S^0)=(15.02\pm0.10\pm0.27\pm0.47)\times10^{-3}$, $\mathcal{B}(D_s^+\to K_S^0π^+)=(1.109\pm0.034\pm0.023\pm0.035)\times10^{-3}$, $\mathcal{B}(D_s^+\to K^+π^0)=(0.748\pm0.049\pm0.018\pm0.023)\times10^{-3}$, where the first uncertainties are statistical, the second are systematic, and the third are from external input branching fraction of the normalization mode $D_s^+\to K^+K^-π^+$. Precision of our measurements is significantly improved compared with that of the current world average values.

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arXiv2020

Measurement of Singly Cabibbo-Suppressed Decays $D \to ωππ$

Using 2.93 fb$^{-1}$ of $e^{+}e^{-}$ collision data taken at a center-of-mass energy of 3.773 GeV by the BESIII detector at the BEPCII, we measure the branching fractions of the singly Cabibbo-suppressed decays $D \to ωππ$ to be $\mathcal{B}(D^0 \to ωπ^+π^-) = (1.33 \pm 0.16 \pm 0.12)\times 10^{-3}$ and $\mathcal{B}(D^+ \to ωπ^+π^0) =(3.87 \pm 0.83 \pm 0.25)\times 10^{-3}$, where the first uncertainties are statistical and the second ones systematic. The statistical significances are $12.9σ$ and $7.7 σ$, respectively. The precision of $\mathcal{B}(D^0 \to ωπ^+π^-)$ is improved by a factor of 2.1 over the CLEO measurement, and $\mathcal{B}(D^+ \to ωπ^+π^0)$ is measured for the first time. No significant signal of $\mathcal{B}(D^0 \to ωπ^0π^0)$ is observed, and the upper limit on the branching fraction is $\mathcal{B}(D^0 \to ωπ^0π^0) < 1.10 \times 10^{-3}$ at the $90\%$ confidence level. The branching fractions of $D\to ηππ$ are also measured and consistent with existing results.

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arXiv2020

Search for the semileptonic decay $D^{0(+)}\to b_1(1235)^{-(0)} e^+ν_e$

Using $2.93~\mathrm{fb}^{-1}$ of $e^+e^-$ annihilation data collected at a center-of-mass energy $\sqrt{s}=3.773$ GeV with the BESIII detector operating at the BEPCII collider, we search for the semileptonic $D^{0(+)}$ decays into a $b_1(1235)^{-(0)}$ axial-vector meson for the first time. No significant signal is observed for either charge combination. The upper limits on the product branching fractions are ${\mathcal B}_{D^0\to b_1(1235)^- e^+ν_e}\cdot {\mathcal B}_{b_1(1235)^-\to ωπ^-}<1.12\times 10^{-4}$ and ${\mathcal B}_{D^+\to b_1(1235)^0 e^+ν_e}\cdot {\mathcal B}_{b_1(1235)^0\to ωπ^0}<1.75\times 10^{-4}$ at the 90\% confidence level.

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arXiv2020

Measurements of the absolute branching fractions of $D^{0(+)}\to K\bar Kππ$ decays

Based on 2.93~fb$^{-1}$ $e^+e^-$ collision data taken at center-of-mass energy of 3.773 GeV by the BESIII detector, we report the measurements of the absolute branching fractions of $D^0\to K^+K^-π^0π^0$, $D^0\to K^0_SK^0_Sπ^+π^-$, $D^0\to K^0_SK^-π^+π^0$, $D^0\to K^0_SK^+π^-π^0$, $D^+\to K^+K^-π^+π^0$, $D^+\to K^0_SK^+π^0π^0$, $D^+\to K^0_SK^-π^+π^+$, $D^+\to K^0_SK^+π^+π^-$, and $D^+\to K^0_SK^0_Sπ^+π^0$. The decays $D^0\to K^+K^-π^0π^0$, $D^0\to K^0_SK^-π^+π^0$, $D^0\to K^0_SK^+π^-π^0$, $D^+\to K^0_SK^0_Sπ^+π^0$, and $D^+\to K^0_SK^+π^0π^0$ are observed for the first time. The branching fractions of the decays $D^0\to K^0_SK^0_Sπ^+π^-$, $D^+\to K^+K^-π^+π^0$, $D^+\to K^0_SK^-π^+π^+$, and $D^+\to K^0_SK^+π^+π^-$ are measured with improved precision compared to the world-average values.

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arXiv2020

Improved model-independent determination of the strong-phase difference between $D^{0}$ and $\bar{D}^{0}\to K^{0}_{\mathrm{S,L}}K^{+}K^{-}$ decays

We present a measurement of the strong-phase difference between $D^{0}$ and $\bar{D}^{0}\to K^{0}_{\rm S,L}K^{+}K^{-}$ decays, performed through a study of quantum-entangled pairs of charm mesons. The measurement exploits a data sample equivalent to an integrated luminosity of 2.93~fb$^{-1}$, collected by the BESIII detector in $e^{+}e^{-}$ collisions corresponding to the mass of the $ψ(3770)$ resonance. The strong-phase difference is an essential input to the determination of the Cabibbo-Kobayashi-Maskawa (CKM) angle $γ/ϕ_3$ through the decay $B^{-}\to DK^{-}$, where $D$ can be either a $D^{0}$ or a $\bar{D}^{0}$ decaying to $K^{0}_{\rm S,L}K^{+}K^{-}$. This is the most precise measurement to date of the strong-phase difference in these decays.

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arXiv2020

Study of open-charm decays and radiative transitions of the X(3872)

The processes $X(3872)\to D^{*0}\bar{D^{0}}+c.c.,~γJ/ψ,~γψ(2S),$ and $γD^{+}D^{-}$ are searched for in a $9.0~\rm fb^{-1}$ data sample collected at center-of-mass energies between $4.178$ and $4.278$ GeV with the BESIII detector. We observe $X(3872)\to D^{*0}\bar{D^{0}}+c.c.$ and find evidence for $X(3872)\toγJ/ψ$ with statistical significances of $7.4σ$ and $3.5σ$, respectively. No evident signals for $X(3872)\toγψ(2S)$ and $γD^{+}D^{-}$ are found, and upper limit on the relative branching ratio $R_{γψ} \equiv\frac{\mathcal{B}(X(3872)\toγψ(2S))}{\mathcal{B}(X(3872)\toγJ/ψ)}<0.59$ is set at 90$\%$ confidence level. Measurements of branching ratios relative to decay $X(3872)\toπ^+π^- J/ψ$ are also reported for decays $X(3872)\to D^{*0}\bar{D^{0}}+c.c., ~γψ(2S),~γJ/ψ$, $γD^{+}D^{-}$, as well as the non-$D^{*0}\bar{D}^{0}$ three-body decays $π^0 D^{0}\bar{D}^{0}$ and $γD^{0}\bar{D}^{0}$.

hep-ex↗

arXiv2020

Search for the decay $J/ψ\toγ+ \rm {invisible}$

We search for $J/ψ$ radiative decays into a weakly interacting neutral particle, namely an invisible particle, using the $J/ψ$ produced through the process $ψ(3686)\toπ^+π^-J/ψ$ in a data sample of $(448.1\pm2.9)\times 10^6$ $ψ(3686)$ decays collected by the BESIII detector at BEPCII. No significant signal is observed. Using a modified frequentist method, upper limits on the branching fractions are set under different assumptions of invisible particle masses up to 1.2 $\mathrm{\ Ge\kern -0.1em V}/c^2$. The upper limit corresponding to an invisible particle with zero mass is 7.0$\times 10^{-7}$ at the 90\% confidence level.

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arXiv2020

Measurement of the Born Cross Sections for $e^+e^-\to D_s^+ D_{s1}(2460)^- +c.c.$ and $e^+e^-\to D_s^{\ast +} D_{s1}(2460)^- +c.c.$

The processes $e^+e^-\to D_s^+ D_{s1}(2460)^- +c.c.$ and $e^+e^-\to D_s^{\ast +} D_{s1}(2460)^- +c.c.$ are studied for the first time using data samples collected with the BESIII detector at the BEPCII collider. The Born cross sections of $e^+e^-\to D_s^+ D_{s1}(2460)^- +c.c.$ at nine center-of-mass energies between 4.467\,GeV and 4.600\,GeV and those of $e^+e^-\to D_s^{\ast +} D_{s1}(2460)^- +c.c.$ at ${\sqrt s}=$ 4.590\,GeV and 4.600\,GeV are measured. No obvious charmonium or charmonium-like structure is seen in the measured cross sections.

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