arXiv subjects

T. Held

Publications and source records attributed to T. Held.

At least 55 records · Page 3Linked to original sources

arXiv2018

Measurements of Absolute Branching Fractions for $Λ^+_c\toΞ^0K^+$ and $Ξ(1530)^0K^+$

We report the first measurements of absolute branching fractions for the $W$-exchange-only processes $Λ^+_c\toΞ^0K^+$ and $Λ^+_c\toΞ(1530)^0K^+$ with the double-tag technique, by analyzing an $e^{+}e^{-}$ collision data sample, that corresponds to an integrated luminosity of 567 pb$^{-1}$ collected at a center-of-mass energy of 4.6 GeV by the BESIII detector. The branching fractions are measured to be $\mathcal{B}(Λ^+_c\toΞ^0K^+)=(5.90\pm0.86\pm0.39)\times10^{-3}$ and $\mathcal{B}(Λ^+_c\toΞ(1530)^0K^+)=(5.02\pm0.99\pm0.31)\times10^{-3}$, where the first uncertainties are statistical and the second systematic. Our results are more precise than the previous relative measurements.

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arXiv2018

Measurement of the absolute branching fraction of the inclusive semileptonic $Λ_c^+$ decay

Using a data sample corresponding to an integrated luminosity of 567 pb$^{-1}$ collected at a center-of-mass energy of $\sqrt{s}=4.6$ GeV with the BESIII detector, we measure the absolute branching fraction of the inclusive semileptonic $Λ_c^+$ decay with a double-tag method. We obtain $\mathcal{B}(Λ_c^+ \rightarrow X e^+ ν_e) = (3.95\pm0.34\pm0.09)\%$, where the first uncertainty is statistical and the second systematic. Using the known $Λ_c^+$ lifetime and the charge-averaged semileptonic decay width of nonstrange charmed measons ($D^0$ and $D^+$), we obtain the ratio of the inclusive semileptonic decay widths $Γ(Λ_c^+ \rightarrow X e^+ ν_e)/\barΓ(D\rightarrow X e^+ ν_e)= 1.26\pm0.12$.

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arXiv2018

Measurement of Singly Cabibbo-Suppressed Decays $D^{0}\toπ^{0}π^{0}π^{0}$, $π^{0}π^{0}η$, $π^{0}ηη$ and $ηηη$

Using a data sample of $e^+e^-$ collision data corresponding to an integrated luminosity of 2.93 $fb^{-1}$ collected with the BESIII detector at a center-of-mass energy of $\sqrt{s}= 3.773~GeV$,we search for the singly Cabibbo-suppressed decays $D^{0}\toπ^{0}π^{0}π^{0}$, $π^{0}π^{0}η$, $π^{0}ηη$ and $ηηη$ using the double tag method. The absolute branching fractions are measured to be $\mathcal{B}(D^{0}\toπ^{0}π^{0}π^{0}) = (2.0 \pm 0.4 \pm 0.3)\times 10^{-4}$, $\mathcal{B}(D^{0}\toπ^{0}π^{0}η) = (3.8 \pm 1.1 \pm 0.7)\times 10^{-4}$ and $\mathcal{B}(D^{0}\toπ^{0}ηη) = (7.3 \pm 1.6 \pm 1.5)\times 10^{-4}$ with the statistical significances of $4.8σ$, $3.8σ$ and $5.5σ$, respectively, where the first uncertainties are statistical and the second ones systematic. No significant signal of $D^{0}\toηηη$ is found, and the upper limit on its decay branching fraction is set to be $\mathcal{B}(D^{0}\toηηη) < 1.3 \times 10^{-4}$ at the $90\%$ confidence level.

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arXiv2018

Precision measurement of the $e^{+}e^{-}~\rightarrow~Λ_{c}^{+} \barΛ_{c}^{-}$ cross section near threshold

The Born cross section of the $e^{+}e^{-}~\rightarrow~Λ_{c}^{+} \barΛ_{c}^{-}$ process is measured with unprecedented precision using data collected with the BESIII detector at $\sqrt{s}=4574.5$, $45580.0$, $4590.0$ and $4599.5$ $\mathrm{MeV}$. The non-zero cross section near the $Λ_{c}^{+} \barΛ_{c}^{-}$ production threshold is discerned. At center-of-mass energies $\sqrt{s}=4574.5$ and $4599.5 $ $\mathrm{MeV}$, the higher statistics data enable us to measure the $Λ_{c}$ polar angle distributions. From these, the ratio between the $Λ_{c}$ electric and magnetic form factors ($|G_{E}/G_{M}|$) is measured for the first time. They are found to be $1.14\pm0.14\pm0.07$ and $1.23\pm0.05\pm0.03$ respectively, where the first uncertainties are statistical and the second are systematic.

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arXiv2018

Search for $h_{c}\rightarrowπ^+π^-J/ψ$ via $ψ(3686)\rightarrow π^0π^+π^-J/ψ$

Using a data sample of $448.1\times10^6$ $ψ(3686)$ events collected with the BESIII detector operating at the BEPCII, we perform search for the hadronic transition $h_c\rightarrowπ^+π^-J/ψ$ via $ψ(3686)\rightarrowπ^0h_c$. No signals of the transition are observed, and the upper limit on the product branching fraction $\mathcal{B}(ψ(3686)\rightarrowπ^0h_c)\mathcal{B}(h_c\rightarrowπ^+π^-J/ψ)$ at the 90% confidence level is determined to be $2.0\times10^{-6}$. This is the most stringent upper limit to date.

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arXiv2018

Study of the decays $D^+\rightarrowη^{(\prime)} e^+ν_{e}$

The charm semileptonic decays $D^+\toηe^+ν_{e}$ and $D^+\toη'e^+ν_{e}$ are studied with a sample of $e^+e^-$ collision data corresponding to an integrated luminosity of 2.93 fb$^{-1}$ collected at $\sqrt{s}$ = 3.773 GeV with the BESIII detector. We measure the branching fractions for $D^+\toηe^+ν_{e}$ to be $(10.74\pm0.81\pm0.51)\times10^{-4}$, and for $D^+\toη'e^+ν_{e}$ to be $(1.91\pm0.51\pm0.13)\times10^{-4}$, where the uncertainties are statistical and systematic, respectively. In addition, we perform a measurement of the form factor in the decay $D^+\toηe^+ν_{e}$. All the results are consistent with those obtained by the CLEO-c experiment.

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arXiv2018

Measurement of absolute branching fraction of the inclusive decay $Λ_{c}^{+} \to Λ+ X$

Based on an $e^+e^-$ collision data sample corresponding to an integrated luminosity of 567$\,\rm{pb}^{-1}$ taken at the center-of-mass energy of $\sqrt{s} = 4.6$ GeV with the BESIII detector, we measure the absolute branching fraction of the inclusive decay $Λ_{c}^{+} \to Λ+ X$ to be $\mathcal{B}(Λ_{c}^{+} \to Λ+ X)=(38.2^{+2.8}_{-2.2}\pm0.8)\%$ using the double-tag method, where $X$ refers to any possible final state particles. In addition, we search for direct CP violation in the charge asymmetry of this inclusive decay for the first time, and obtain $\mathcal{A}_{CP} \equiv \frac{\mathcal{B}(Λ_{c}^{+} \to Λ+ X)-\mathcal{B}(\barΛ_{c}^{-} \to \barΛ + X)}{\mathcal{B}(Λ_{c}^{+} \to Λ+ X)+\mathcal{B}(\barΛ_{c}^{-} \to \barΛ + X)} = (2.1^{+7.0}_{-6.6}\pm1.4)\%$, a statistically limited result with no evidence of CP violation.

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arXiv2018

Search for Baryon and Lepton Number Violation in $J/ψ\toΛ_c^+e^-+c.c.$

Using $1.31\times10^9$ $J/ψ$ events collected by the BESIII detector at the Beijing Electron Positron Collider, we search for the process $J/ψ\toΛ_c^+e^-+c.c.$ for the first time. In this process, both baryon and lepton number conservation is violated. No signal is found and the upper limit on the branching fraction $\mathcal{B}(J/ψ\toΛ_c^+e^-+c.c.)$ is set to be $6.9\times10^{-8}$ at the 90\% Confidence Level.

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arXiv2018

Observation of the Semileptonic Decay $D^0 \to a_0(980)^- e^+ ν_e$ and Evidence for $D^+ \to a_0(980)^0 e^+ ν_e$

Using an $e^+e^-$ collision data sample of 2.93 fb$^{-1}$ collected at a center-of-mass energy of 3.773 GeV by the BESIII detector at BEPCII, we report the observation of $D^0 \to a_0(980)^- e^+ ν_e$ and evidence for $D^+ \to a_0(980)^0 e^+ ν_e~$ with significances of $6.4σ$ and $2.9σ$, respectively. The absolute branching fractions are determined to be $\mathcal{B}(D^0 \to a_0(980)^- e^+ ν_e)\times\mathcal{B}(a_0(980)^- \to ηπ^-) = (1.33_{-0.29}^{+0.33}({\rm stat})\pm0.09({\rm syst}))\times10^{-4}~$ and $\mathcal{B}(D^+ \to a_0(980)^0 e^+ ν_e)\times\mathcal{B}(a_0(980)^0 \to ηπ^0) = (1.66_{-0.66}^{+0.81}({\rm stat})\pm0.11({\rm syst}))\times10^{-4}~$. An upper limit of $\mathcal{B}(D^+ \to a_0(980)^0 e^+ ν_e)\times\mathcal{B}(a_0(980)^0 \to ηπ^0)<3.0\times10^{-4}~$ is also determined at the $90\%~$ confidence level.

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arXiv2018

Observation of $e^{+}e^{-} \to ϕχ_{c1}$ and $ϕχ_{c2}$ at $\sqrt{s}$=4.600 GeV

Using a data sample collected with the BESIII detector operating at the BEPCII storage ring at a center-of-mass energy of $\sqrt{s}=4.600$ GeV, we search for the production of $e^{+}e^{-} \to ϕχ_{c0,1,2}$ and the charmonium-like state $Y(4140)$ in the radiative transition $e^{+}e^{-} \to γY(4140)$ with $Y(4140)$ subsequently decaying into $ϕJ/ψ$. The processes $e^{+}e^{-} \to ϕχ_{c1}$ and $ϕχ_{c2}$ are observed for the first time, each with a statistical significance of more than 10σ, and the Born cross sections are measured to be $(4.2^{+1.7}_{-1.0}\pm 0.3)$ pb and $(6.7^{+3.4}_{-1.7}\pm 0.5)$ pb, respectively, where the first uncertainties are statistical and the second systematic. No significant signals are observed for $e^{+}e^{-} \to ϕχ_{c0}$ and $e^{+}e^{-} \to γY(4140)$ and upper limits on the Born cross sections at $90\%$ confidence level are provided at $\sqrt{s}=4.600$ GeV.

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arXiv2018

Measurements of the Branching Fractions of the Singly-Cabibbo-Suppressed Decays $D^0\toωη$, $η^{(\prime)}π^0$ and $η^{(\prime)}η$

By analyzing a data sample of 2.93 fb$^{-1}$ collected at $\sqrt s=$ 3.773 GeV with the BESIII detector operated at the BEPCII storage rings, we measure the branching fractions ${\mathcal B}(D^0\toωη)=(2.15\pm0.17_{\rm stat.}\pm0.15_{\rm sys.})\times 10^{-3}$, ${\mathcal B}(D^0\toηπ^0)=(0.58\pm0.05_{\rm stat.}\pm0.05_{\rm sys.})\times 10^{-3}$, ${\mathcal B}(D^0\toη^\primeπ^0)=(0.93\pm0.11_{\rm stat.}\pm0.09_{\rm sys.})\times 10^{-3}$, ${\mathcal B}(D^0\toηη)=(2.20\pm0.07_{\rm stat.}\pm0.06_{\rm sys.})\times 10^{-3}$ and ${\mathcal B}(D^0\toη^\primeη)=(0.94\pm0.25_{\rm stat.}\pm0.11_{\rm sys.})\times 10^{-3}$. We note that ${\mathcal B}(D^0\to ωη)$ is measured for the first time and that ${\mathcal B}(D^0\to ηη)$ is measured with much improved precision.

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arXiv2018

Study of two-photon decays of pseudoscalar mesons via $J/ψ$ radiative decays

Using a sample of $4.48\times10^{8}$ $ψ(3686)$ events collected with the BESIII detector at the BEPCII collider, we study the two-photon decays of the pseudoscalar mesons $π^0$, $η$, $η^\prime$, $η(1405)$, $η(1475)$, $η(1760)$, and $X(1835)$ in $J/ψ$ radiative decays using $ψ(3686)\toπ^{+}π^{-}J/ψ$ events. The $π^0$, $η$ and $η^\prime$ mesons are clearly observed in the two-photon mass spectra, and the branching fractions are determined to be $B(J/ψ\toγπ^{0}\to3γ)=(3.57\pm0.12\pm0.16)\times10^{-5}$, $B(J/ψ\toγη\to3γ)=(4.42\pm0.04\pm0.18)\times10^{-4}$, and $B(J/ψ\toγη'\to3γ)=(1.26\pm0.02\pm0.05)\times10^{-4}$, where the first errors are statistical and the second systematic. No clear signal for $η(1405)$, $η(1475)$, $η(1760)$ or $X(1835)$ is observed in the two-photon mass spectra, and upper limits at the $90\%$ confidence level on the product branching fractions are obtained.

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arXiv2018

Measurements of absolute branching fractions for $D$ mesons decays into two pseudoscalar mesons

Using a data sample of $e^+e^-$ collision data with an integrated luminosity of 2.93 fb$^{-1}$ taken at the center-of-mass energy $\sqrt s= 3.773$~GeV with the BESIII detector operating at the BEPCII storage rings, we measure the absolute branching fractions of the two-body hadronic decays $D^+\to π^+π^0$, $K^+ π^0$, $π^+ η$, $K^+η$, $π^+η^\prime$, $K^+η^\prime$, $K_S^0 π^+$, $K_S^0 K^+$, and $D^0\to π^+ π^-$, $K^+ K^-$, $K^\mp π^\pm$, $K_S^0 π^0$, $K_S^0 η$, $K_S^0 η^\prime$. Our results are consistent with previous measurements within uncertainties. Among them, the branching fractions for $D^+\toπ^+π^0$, $K^+π^0$, $π^+η$, $π^+η^\prime$, $K_S^0 π^+$, $K_S^0 K^+$ and $D^0 \to K_S^0 π^0$, $K_S^0 η$, $K_S^0 η^\prime$ are determined with improved precision compared to the world average values.

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arXiv2018

Observation of $e^{+}e^{-} \rightarrow K\bar{K}J/ψ$ at center-of-mass energies from 4.189 to 4.600 GeV

We investigate the process $e^{+}e^{-} \rightarrow K\bar{K}J/ψ$ at center-of-mass energies from 4.189 to 4.600 GeV using 4.7 fb$^{-1}$ of data collected by the BESIII detector at the BEPCII collider. The Born cross sections for the reactions $e^{+}e^{-} \rightarrow K^{+}K^{-}J/ψ$ and $K_{S}^{0} K_{S}^{0} J/ψ$ are measured as a function of center-of-mass energy. The energy dependence of the cross section for $e^{+}e^{-} \rightarrow K^{+}K^{-}J/ψ$ is shown to differ from that for $π^{+}π^{-}J/ψ$ in the region around the $Y(4260)$. In addition, there is evidence for a structure around 4.5 GeV in the $e^{+}e^{-} \rightarrow K^{+}K^{-}J/ψ$ cross section that is not present in $π^{+}π^{-}J/ψ$.

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arXiv2018

Measurement of the matrix elements for the decays $η^{\prime}\rightarrowηπ^+π^-$ and $η^{\prime}\rightarrowηπ^0π^0$

Based on a sample of $1.31\times10^9$ $J/ψ$ events collected with the BESIII detector, the matrix elements for the decays $η^{\prime}\toηπ^{+}π^{-}$ and $η^{\prime}\toηπ^{0}π^{0}$ are determined using 351,016 $η^{\prime}\to(η\toγγ)π^+π^-$ and 56,249 $η^{\prime}\to(η\toγγ)π^0π^0$ events with background levels less than 1\%. Two commonly used representations are used to describe the Dalitz plot density. We find that an assumption of a linear amplitude does not describe the data well. A small deviation of the obtained matrix elements between $η^{\prime}\toηπ^{+}π^{-}$ and $η^{\prime}\toηπ^{0}π^{0}$ is probably caused by the mass difference between charged and neutral pions or radiative corrections. No cusp structure in $η^{\prime}\toηπ^{0}π^{0}$ is observed.

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arXiv2018

Search for $ψ(3686)\to γη_c(η(1405))\to γπ^{+}π^{-}π^{0}$

Using a sample of $448.1\times10^{6}$ $ψ(3686)$ events collected with the BESIII detector, a search for the isospin violating decay $η_{c}\toπ^{+}π^{-}π^{0}$ via $ψ(3686)\toγη_{c}$ is presented. No signal is observed, and the upper limit on $\mathcal{B}(ψ(3686)\to γη_{c}\to γπ^{+}π^{-}π^{0} )$ is determined to be $1.6\times10^{-6}$ at the $90\%$ confidence level. In addition, a search for $η(1405)\to f_{0}(980)π^{0}$ in $ψ(3686)$ radiative decays is performed. No signal is observed, and the branching fraction $\mathcal{B}(ψ(3686)\toγη(1405)\to γf_{0}(980)π^{0}\toγπ^+π^-π^0 )$ is calculated to be less than $ 5.0\times10^{-7}$ at the $90\%$ confidence level.

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arXiv2017

Observation of $χ_{c2}\toη'η'$ and $χ_{c0,2}\toηη'$

Using a sample of $447.9\times 10^6$ $ψ(3686)$ events collected with the BESIII detector in 2009 and 2012, we study the decays $χ_{c0,2}\to$ $η'η'$ and $ηη'$. The decays $χ_{c2}\toη'η'$, $χ_{c0}\toηη'$ and $χ_{c2}\toηη'$ are observed for the first time with statistical significances of $9.6σ$, $13.4σ$ and $7.5σ$, respectively. The branching fractions are determined to be $\mathcal{B}(χ_{c0}\toη'η') =(2.19\pm0.03\pm0.14)\times10^{-3}$, $\mathcal{B}(χ_{c2}\toη'η') = (4.76\pm0.56\pm0.38)\times10^{-5}$, $\mathcal{B}(χ_{c0}\toηη') = (8.92\pm0.84\pm0.65)\times10^{-5}$ and $\mathcal{B}(χ_{c2}\toηη') = (2.27\pm0.43\pm0.25)\times10^{-5}$, where the first uncertainties are statistical and the second systematic. The precision for the measurement of $\mathcal{B}(χ_{c0}\toη'η')$ is significantly improved compared to previous measurements. Based on the measured branching fractions, the role played by the doubly and singly Okubo-Zweig-Iizuka disconnected transition amplitudes for $χ_{c0,2}$ decays into pseudoscalar meson pairs can be clarified.

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arXiv2017

Measurement of the absolute branching fraction of $D_{s0}^{*\pm}(2317)\to π^0 D_{s}^{\pm}$

The process $e^+ e^- \to D_{s}^{*+} D_{s0}^{*-}(2317)+c.c.$ is observed for the first time with the data sample of 567~pb$^{-1}$ collected with the BESIII detector operating at the BEPCII collider at a center-of-mass energy $\sqrt{s} = 4.6$~GeV. The statistical significance of the $D_{s0}^{*-}(2317)$ signal is $5.8σ$ and the mass is measured to be ($2318.3\pm 1.2\pm 1.2$)~MeV/$c^{2}$. The absolute branching fraction $\mathcal{B}(D_{s0}^{*-}(2317)\to π^0 D_{s}^{-})$ is measured as $1.00^{+0.00}_{-0.14}\pm 0.14$ for the first time. The uncertainties are statistical and systematic, respectively.

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