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S. C. Coen

Publications and source records attributed to S. C. Coen.

At least 73 records · Page 4Linked to original sources
arXiv2023

Measurement of $e^{+}e^{-}\toϕη'$ cross sections at center-of-mass energies from 3.508 to 4.951 GeV and search for the decay $ψ(3770)\toϕη'$

The cross sections of the $e^{+}e^{-}\toϕη'$ process at center-of-mass energies from 3.508 to 4.951 GeV are measured with high precision using 26.1 fb$^{-1}$ data collected with the BESIII detector operating at the BEPCII storage ring. The cross sections are of the order of a few picobarn, and decrease as the center-of-mass energy increases as $s^{-n/2}$ with $n=4.35\pm 0.14$. This result is in agreement with the Nambu-Jona-Lasinio model prediction of $n=3.5\pm 0.9$. In addition, the charmless decay $ψ(3770)\toϕη'$ is searched for by fitting the measured cross sections, yet no significant signal is observed. The upper limit of ${\cal B}(ψ(3770)\toϕη')$ at the 90\% confidence level is determined to be $2.3\times 10^{-5}$.

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arXiv2023

Search for the semileptonic decays $D^+_s \to K_1(1270)^0 e^+ν_e$ and $D^+_s \to b_1(1235)^0 e^+ν_e$

By analyzing 7.33\,fb$^{-1}$ of $e^+e^-$ collision data collected at center-of-mass energies between 4.128 and 4.226 GeV with the BESIII detector, we search for the semileptonic decays $D^+_s \to K_1(1270)^0 e^+ν_e$ and $D^+_s \to b_1(1235)^0 e^+ν_e$ for the first time. No significant signals are observed for either decay mode. The upper limits on the (product) branching fractions are determined to be ${\mathcal B}[D^+_s \to K_1(1270)^0 e^+ν_e] < 4.1\times 10^{-4}$ and ${\mathcal B}[D^+_s \to b_1(1235)^0 e^+ν_e]\cdot {\mathcal B}[b_1(1235)^0\to ωπ^0] < 6.4\times 10^{-4}$ at 90\% confidence level.

hep-ex↗
arXiv2023

Search for a scalar partner of the $X(3872)$ via $ψ(3770)$ decays into $γηη'$ and $γπ^{+}π^{-}J/ψ$

Using a data sample corresponding to an integrated luminosity of 2.93 fb$^{-1}$ collected at a center-of-mass energy of 3.773~GeV with the BESIII detector at the BEPCII collider, we search for a scalar partner of the $X(3872)$, denoted as $X(3700)$, via $ψ(3770)\to γηη'$ and $γπ^{+}π^{-}J/ψ$ processes. No significant signals are observed and the upper limits of the product branching fractions $ {\cal B}(ψ(3770)\toγX(3700))\cdot {\cal B}(X(3700)\to ηη')$ and ${\cal B}(ψ(3770)\toγX(3700))\cdot {\cal B}(X(3700)\toπ^{+}π^{-}J/ψ)$ are determined at the 90\% confidence level, for the narrow $X(3700)$ with a mass ranging from 3710 to 3740 MeV/$c^2$, which are from 0.8 to 1.8 $(\times 10^{-5})$ and 0.9 to 3.4 $(\times 10^{-5})$, respectively.

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arXiv2023

A coupled-channel analysis of the $X(3872)$ lineshape with BESIII data

We perform a study of the $X(3872)$ lineshape using the data samples of $e^+e^-\toγX(3872)$, $X(3872)\to D^0\bar{D}^0 π^0$ and $π^+π^- J/ψ$ collected with the BESIII detector. The effects of the coupled-channels and the off-shell $D^{*0}$ are included in the parameterization of the lineshape. The lineshape mass parameter is obtained to be $M_{X}=(3871.63\pm 0.13^{+0.06}_{-0.05})$ MeV. Two poles are found on the first and second Riemann sheets corresponding to the $D^{*0}\bar{D}^0$ branch cut. The pole location on the first sheet is much closer to the $D^{*0}\bar{D}^0$ threshold than the other, and is determined to be $7.04\pm0.15^{+0.07}_{-0.08}$ MeV above the $D^0\bar{D}^0π^0$ threshold with an imaginary part $-0.19\pm0.08^{+0.14}_{-0.19}$ MeV.

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arXiv2023

Measurements of the branching fractions of the inclusive decays $D^{0}(D^{+})\to π^+π^+π^-X$

Using $e^+e^-$ annihilation data corresponding to an integrated luminosity of 2.93 fb$^{-1}$ taken at a center-of-mass energy of 3.773 GeV with the BESIII detector, we report the first measurements of the branching fractions of the inclusive decays $D^0\to π^+π^+π^-X$ and $D^+\to π^+π^+π^-X$, where pions from $K^0_S$ decays have been excluded from the $π^+π^+π^-$ system and $X$ denotes any possible particle combination. The branching fractions of $D^0(D^+)\to π^+π^+π^-X$ are determined to be ${\mathcal B}(D^0\to π^+π^+π^-X)=(17.60\pm0.11\pm0.22)\%$ and ${\mathcal B}(D^+\to π^+π^+π^-X)=(15.25\pm0.09\pm0.18)\%$, where the first uncertainties are statistical and the second systematic.

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arXiv2023

Measurement of branching fractions of $Λ_{c}^{+}$ decays to $Σ^{+} K^{+} K^{-}$, $Σ^{+}ϕ$ and $Σ^{+} K^{+} π^{-}(π^{0})$

Based on 4.5 fb$^{-1}$ data taken at seven center-of-mass energies ranging from 4.600 to 4.699 GeV with the BESIII detector at the BEPCII collider, we measure the branching fractions of $Λ_{c}^{+}\rightarrowΣ^{+}+hadrons$ relative to $Λ_{c}^{+}\rightarrow Σ^+ π^+ π^-$. Combining with the world average branching fraction of $Λ_{c}^{+}\rightarrow Σ^+ π^+ π^-$, their branching fractions are measured to be $(0.377\pm0.042\pm0.018\pm0.021)\%$ for $Λ_{c}^{+}\rightarrowΣ^{+} K^{+} K^{-}$, $(0.200\pm0.023\pm0.010\pm0.011)\%$ for $Λ_{c}^{+}\rightarrowΣ^{+} K^{+} π^{-}$, $(0.414\pm0.080\pm0.029\pm0.023)\%$ for $Λ_{c}^{+}\rightarrowΣ^{+}ϕ$ and $(0.197\pm0.036\pm0.008\pm0.011)\%$ for $Λ_{c}^{+}\rightarrowΣ^{+}K^{+} K^{-}$(non-$ϕ$). In all the above results, the first uncertainties are statistical, the second are systematic and the third are from external input of the branching fraction of $Λ_{c}^{+}\rightarrow Σ^+ π^+ π^-$. Since no signal for $Λ_{c}^{+}\rightarrowΣ^{+} K^{+} π^{-}π^{0}$ is observed, the upper limit of its branching fraction is determined to be 0.11\% at the 90$\%$ confidence level.

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arXiv2023

Measurement of the branching fraction of $D_s^+\to τ^+ ν_τ$ via $τ^+ \to μ^+ ν_μ\bar{ν_τ}$

Utilizing $7.33~\mathrm{fb}^{-1}$ of $e^+e^-$ collision data taken at the center-of-mass energies of 4.128, 4.157, 4.178, 4.189, 4.199, 4.209, 4.219, and 4.226 GeV with the BESIII detector, the branching fraction of the leptonic decay $D_s^+\toτ^+ν_τ$ via $τ^+\toμ^+ν_μ\bar ν_τ$ is measured to be $\mathcal{B}_{D_s^+\toτ^+ν_τ}=(5.34\pm0.16_{\rm stat}\pm0.10_{\rm syst})\%$. Combining this branching fraction with the world averages of the measurements of the masses of $τ^+$ and $D_s^+$ as well as the lifetime of $D_s^+$, we extract the product of the decay constant of $D_s^+$ and the $c\to s$ Cabibbo-Kobayashi-Maskawa matrix element to be $f_{D_s^+}|V_{cs}|=(246.2\pm3.7_{\rm stat}\pm2.5_{\rm syst})~\mathrm{MeV}$. Taking $|V_{cs}|$ from a global fit in the standard model we obtain $f_{D_s^+}=(252.7\pm3.8_{\rm stat}\pm2.6_{\rm syst})$ MeV. Conversely, taking $f_{D_s^+}$ from lattice quantum chromodynamics calculations, we obtain $|V_{cs}| = 0.984\pm0.015_{\rm stat}\pm0.010_{\rm syst}$.

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arXiv2023

Improved measurement of the branching fractions for $J/ψ\toγπ^0$, $γη$ and $γη^\prime$

Using a data sample of $(1.0087\pm 0.0044)\times 10^{10}$ $J/ψ$ events collected with the BESIII detector, the decays of $J/ψ\toγπ^{0} (η, η^\prime)\toγγγ$ are studied. Newly measured branching fractions are $\mathcal{B}$$(J/ψ\toγπ^{0})$=$(3.34\pm 0.02\pm 0.09)\times 10^{-5}$, $\mathcal{B}$$(J/ψ\toγη)$=$(1.096\pm 0.001\pm0.019)\times 10^{-3}$ and $\mathcal{B}$$(J/ψ\toγη^\prime)$=$(5.40\pm 0.01\pm0.11)\times 10^{-3}$, where the first uncertainties are statistical and the second are systematic. These results are consistent with the world average values within two standard deviations. The ratio of partial widths $Γ(J/ψ\toγη^\prime)/Γ(J/ψ\toγη)$ is measured to be $4.93 \pm 0.13$. The singlet-octet pseudoscalar mixing angle $θ_P$ is determined to be $θ_P = -(22.11 \pm0.26)^\circ$ or $-(19.34 \pm 0.34)^\circ$ with two different phenomenological models.

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arXiv2023

Measurement of $e^{+}e^{-}\toϕπ^{+}π^{-}$ cross sections at center-of-mass energies from 2.00 to 3.08 GeV

Using data corresponding to an integrated luminosity of $651~\mathrm{pb}^{-1}$ accumulated at 22 center-of-mass energies from 2.00 to 3.08 GeV by the BESIII experiment, the process $e^{+}e^{-}\toϕπ^{+}π^{-}$ is studied. The cross sections for $e^{+}e^{-}\toϕπ^{+}π^{-}$ are consistent with previous results, but with improved precision. To measure the mass and width of the structure observed in the cross section line shape, a combine fit is performed after enhancing the contribution from $ϕf_{0}(980)$. The fit reveals a structure with the mass of $M=2178\pm20\pm5~{\rm MeV}/c^2$ and the width of $\varGamma=140\pm36\pm16~{\rm MeV}$, where the first uncertainties are statistical and the second ones are systematic.

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arXiv2023

Tests of $CP$ symmetry in the entangled $Ξ^0-\barΞ^0$ Pairs

The $J/ψ\to Ξ^0 \barΞ^{0}$ process and subsequent decays are investigated using $(10087 \pm 44)\times 10^6$ $J/ψ$ events collected at the BESIII experiment. The decay parameters of $Ξ^0$ and $\barΞ^0$ are measured with greatly improved precision over previous measurements to be $α_Ξ = -0.3750 \pm 0.0034 \pm 0.0016$, $\barα_Ξ = 0.3790 \pm 0.0034 \pm 0.0021$, $ϕ_Ξ = 0.0051 \pm 0.0096 \pm 0.0018$~rad, $\barϕ_Ξ = -0.0053 \pm 0.0097 \pm 0.0019$~rad, where the first and the second uncertainties are statistical and systematic, respectively. From these measurements, precise $CP$ symmetry tests in $Ξ^0$ decay are performed, and $A^Ξ_{CP} = (-5.4 \pm 6.5 \pm 3.1) \times 10^{-3}$ and $Δϕ^Ξ_{CP} = (-0.1 \pm 6.9 \pm 0.9) \times 10^{-3}$~rad are consistent with $CP$ conservation. The sequential decay also enables a separation of weak and strong phase differences, which are found for the first time to be $ξ_{P}-ξ_{S} = (0.0 \pm 1.7 \pm 0.2) \times 10^{-2}$~rad and $δ_{P}-δ_{S} = (-1.3 \pm 1.7 \pm 0.4)\times 10^{-2}$~rad, respectively. In addition, we measure the $Λ$ decay parameters and test $CP$ symmetry in $Λ$ decays.

hep-ex↗
arXiv2023

Search for the lepton number violation decay $ϕ\to π^+ π^+ e^- e^-$ via $J/ψ\to ϕη$

Using $(1.0087\pm0.0044)\times10^{10}$ $J/ψ$ events collected by the BESIII detector at the BEPCII collider, we search for the lepton number violation decay $ϕ\to π^+ π^+ e^- e^-$ via $J/ψ\to ϕη$. No signal is found and the upper limit on the branching fraction of $ϕ\to π^+ π^+ e^- e^-$ is set to be $9.7\times10^{-6}$ at the 90\% confidence level.

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arXiv2023

Measurement of the $e^+e^- \to Λ\barΣ^0 + c.c.$ cross sections at $\sqrt{s}$ from 2.3094 to 3.0800 GeV

The Born cross sections and effective form factors of the process $e^+e^-\toΛ\barΣ^0 + c.c.$ are measured at 14 center-of-mass energy points from 2.3094 to 3.0800 GeV, based on data corresponding to an integrated luminosity of $(478.5 \pm 4.8)\ \text{pb}^{-1}$ collected with the BESIII detector. A non-zero Born cross section is observed at the center-of-mass energy of 2.3094 GeV with a statistical significance of more than five standard deviations, and the cross sections at other energies are obtained with improved precision compared to earlier measurements from the BaBar Collaboration. The Born cross-section lineshape is described better by a shape with a plateau near the threshold than by a pQCD motivated functional form.

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arXiv2023

Measurement of the absolute branching fraction of the inclusive decay $\barΛ_{c}^{-} \to \bar{n} + X$

Based on $e^+e^-$ collision data corresponding to an integrated luminosity of 4.5 $fb^{-1}$ collected at the center-of-mass energies between 4.600 and 4.699 GeV with the BESIII detector at BEPCII, the absolute branching fraction of the inclusive decay $Λ^{+}_{c}\to n + X$, where $X$ refers to any possible final state particles, is measured. The absolute branching fraction is determined to be $\mathcal{B}(Λ^{+}_{c}\to n + X) = (32.4 \pm 0.7 \pm 1.5)\% $, where the first uncertainty is statistical and the second systematic. Assuming $CP$ symmetry, the measurement indicates that about one-fourth of $Λ^{+}_{c}$ ($\barΛ_{c}^-$) decay modes with a neutron (an anti-neutron) in the final state have not been observed.

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arXiv2023

Amplitude analysis and branching fraction measurement of the decay $D^{+} \to K_S^0π^+π^0π^0$

Using 2.93 $\rm{fb}^{-1}$ of $e^+e^-$ collision data collected with the BESIII detector at the center-of-mass energy 3.773\,GeV, we perform the first amplitude analysis of the decay $D^+\to K_S^0π^+π^0π^0$ and determine the relative magnitudes and phases of different intermediate processes. The absolute branching fraction of $D^+\to K_S^0π^+π^0π^0$ is measured to be $(2.888\pm0.058_{\rm stat.}\pm0.069_{\rm syst.})\%$. The dominant intermediate processes are $D^+\to K_S^0a_1(1260)^+(\to ρ^+π^0)$ and $D^+\to \bar{K}^{*0}ρ^+$, with branching fractions of $(8.66\pm1.04_{\rm stat.}\pm1.39_{\rm syst.})\!\times \!10^{-3}$ and $(9.70\pm0.81_{\rm stat.}\pm0.53_{\rm syst.})\!\times \!10^{-3}$, respectively.

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arXiv2023

Measurement of the absolute branching fraction of the inclusive decay $D_s^+\to π^+π^+π^- X$

Using an $e^+ e^-$ collision data sample with a total integrated luminosity of $3.19$ fb$^{-1}$ collected with the BESIII detector at a center-of-mass energy of 4.178 GeV, the branching fraction of the inclusive decay of the $D_s^+$ meson to final states including at least three charged pions is measured for the first time to be ${\cal B}(D_s^+\toπ^+ π^+ π^- X) = (32.81 \pm 0.35_{\rm stat} \pm {0.63_{\rm syst}})\%$. In this measurement the charged pions from $K_S^0$ meson decays are excluded. The partial branching fractions of $D_s^+\toπ^+ π^+ π^- X$ are also measured as a function of the $π^+ π^+ π^-$ invariant mass.

hep-ex↗
arXiv2023

Observation of the decay $J/ψ\to e^+ e^- η(1405)$ with $η(1405) \to π^0 f_0(980)$

Using a data sample of $(10087\pm44)\times 10^6$ $J/ψ$ events collected by the BESIII detector in 2009, 2012, 2018 and 2019, the electromagnetic Dalitz process $J/ψ\to e^+ e^- η(1405)$ is observed via the decay $η(1405) \to π^0 f_0(980)$, $f_0(980) \to π^+ π^-$, with a significance of about $9.6σ$. The branching fraction of this decay is measured to be ${\mathcal B}(J/ψ\to e^+ e^- π^0 η(1405) \to e^+ e^- π^0 f_0(980) \to e^+ e^- π^0 π^+ π^-)=(2.02\pm0.24(\rm{stat.})\pm0.09(\rm{syst.}))\times 10^{-7}$. The branching-fraction ratio ${\mathcal B}(J/ψ\to e^+ e^- η(1405))$/${\mathcal B}(J/ψ\to γη(1405))$ is determined to be $(1.35\pm0.19(\rm{stat.})\pm0.06(\rm{syst.}))\times10^{-2}$. Furthermore, an $e^+e^-$ invariant-mass dependent transition form factor of $J/ψ\to e^+ e^-η(1405)$ is presented for the first time. The obtained result provides input for different theoretical models, and is valuable for the improved understanding the intrinsic structure of the $η(1405)$ meson.

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arXiv2023

Studies of the decay $D^+_s\to K^+K^- μ^+ ν_μ$

The $D^+_s\to K^+K^-μ^+ν_μ$ decay is studied based on 7.33 fb$^{-1}$ of $e^+e^-$ collision data collected with the BESIII detector at center-of-mass energies in the range from 4.128 to 4.226 GeV. The absolute branching fraction is measured as ${\mathcal B}(D^+_s\to ϕμ^+ν_μ) = (2.25\pm 0.09 \pm 0.07) \times10^{-2}$, the most precise measurement to date. Combining with the world average of ${\mathcal B}(D^+_s\to ϕe^+ν_e)$, the ratio of the branching fractions obtained is$\frac{{\mathcal B}(D^+_s\to ϕμ^+ν_μ)}{{\mathcal B}(D^+_s\to ϕe^+ν_e)} = 0.94\pm0.08$, in agreement with lepton universality. By performing a partial wave analysis, the hadronic form factor ratios at $q^{2}=0$ are extracted, finding $r_{V}=\frac{V(0)}{A_{1}(0)}=1.58\pm0.17\pm0.02$ and $r_{2}=\frac{A_{2}(0)}{A_{1}(0)}=0.71\pm0.14\pm0.02$, where the first uncertainties are statistical and the second are systematic. No significant $S$-wave contribution from $f_0(980)\to K^+K^-$ is found. The upper limit $\mathcal{B}(D_s^+\to f_0(980)μ^{+}ν_μ) \cdot{\mathcal B}(f_0(980)\to K^+K^-) < 5.45 \times 10^{-4}$ is set at 90\% confidence level.

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arXiv2023

Production of doubly-charged $Δ$ baryon in $e^{+}e^{-}$ annihilation at energies from 2.3094 to 2.6464 GeV

The processes $e^{+}e^{-} \to Δ^{++}\barΔ^{--}$ and $e^{+}e^{-}\to Δ^{++} \bar{p} π^{-} + c.c.$ are studied for the first time with $179~{\rm pb}^{-1}$ of $e^{+}e^{-}$ annihilation data collected with the BESIII detector at center-of-mass energies from $2.3094$ GeV to $2.6464$ GeV. No significant signal for the $e^{+}e^{-}\to Δ^{++}\barΔ^{--}$ process is observed and the upper limit of the Born cross section is estimated at each energy point. For the process $e^{+}e^{-} \to Δ^{++} \bar{p} π^{-} + c.c.$, a significant signal is observed at center-of-mass energies near 2.6454 GeV and the corresponding Born cross section is reported.

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