arXiv subjects

J. P. Dai

Publications and source records attributed to J. P. Dai.

At least 505 records · Page 28Linked to original sources

arXiv2022

Measurement of $e^{+}e^{-} \to K^{+}K^{-}π^{0}$ cross section and observation of a resonant structure

Based on $e^{+}e^{-}$ collision data collected by the BESIII detector at the BEPCII collider at center-of-mass energies from 2.000 to 3.080 GeV, a partial-wave analysis is performed for the process $e^{+}e^{-} \to K^{+}K^{-}π^{0}$. The Born cross section of the process $e^{+}e^{-} \to K^{+}K^{-}π^{0}$ and its subprocesses $e^{+}e^{-} \to ϕπ^{0}$, $K^{*}(892)K$ and $K^{*}_{2}(1430)K$ are measured. The results for $e^{+}e^{-} \to K^{+}K^{-}π^{0}$ and $ϕπ^{0}$ are consistent with the BaBar measurements and with improved precision. By analyzing the cross section, of the subprocesses $e^{+}e^{-} \to$ $K^{*}(892)K$ and $K^{*}_{2}(1430)K$, a structure with mass $M_R$ = (2208 $\pm$ 19 $\pm$ 24) MeV/$c^{2}$ and width $Γ_R$ = (168 $\pm$ 24 $\pm$ 39) MeV is observed with a combined statistical significance of 7.6$σ$. The measured resonance parameters suggest it can be identified as the $ϕ(2170)$, thus the results provide valuable input to understand the internal nature of this state.

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arXiv2022

Measurement of the Cross Section for $e^{+}e^{-}\to$ hadrons at Energies from 2.2324 to 3.6710 GeV

Based on electron-positron collision data collected with the BESIII detector operating at the Beijing Electron Positron Collider II storage rings, the value of $R\equivσ(e^{+}e^{-}\to$hadrons)/$σ(e^{+}e^{-}\toμ^{+}μ^{-})$ is measured at 14 center-of-mass energies from 2.2324 to 3.6710 GeV. The resulting uncertainties are less than $3.0\%$, and are dominated by systematic uncertainties.

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arXiv2022

Observation of a state $X(2600)$ in the $π^{+}π^{-}η'$ system in the process $J/ψ\rightarrowγπ^{+}π^{-}η'$

Based on $(10087\pm44)\times10^{6}$ $J/ψ$ events collected with the BESIII detector, the process $J/ψ\rightarrowγπ^{+}π^{-}η'$ is studied using two dominant decay channels of the $η'$ meson, $η'\rightarrowγπ^{+}π^{-}$ and $η'\rightarrowηπ^{+}π^{-},η\rightarrowγγ$. The $X(2600)$ is observed with a statistical significance larger than 20$σ$ in the $π^{+}π^{-}η'$ invariant mass spectrum, and it has a strong correlation to a structure around 1.5$~\mathrm{GeV}$/{\it c}$^{2}$ in the $π^{+}π^{-}$ invariant mass spectrum. A simultaneous fit on the $π^{+}π^{-}η'$ and $π^{+}π^{-}$ invariant mass spectra with the two $η'$ decay modes indicates that the mass and width of the $X(2600)$ state are $2617.8\pm2.1 ^{+18.2}_{-1.9}~\mathrm{MeV}$/{\it c}$^{2}$ and $200\pm8^{+20}_{-17}~\mathrm{MeV}$, respectively. The corresponding branching fractions are measured to be $B(J/ψ\rightarrowγX(2600))\cdot B(X(2600)\rightarrow f_{0}(1500)η')\cdot B(f_{0}(1500)\rightarrowπ^{+}π^{-})$ = ($3.39\pm0.18^{+0.91}_{-0.66})\times10^{-5}$ and $B(J/ψ\rightarrowγX(2600))\cdot B(X(2600)\rightarrow f_{2}^{'}(1525)η')\cdot B(f_{2}^{'}(1525)\rightarrowπ^{+}π^{-})$ = ($2.43\pm0.13^{+0.31}_{-1.11})\times10^{-5}$, where the first uncertainties are statistical, and the second systematic.

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arXiv2022

Search for a $CP$-odd light Higgs boson in $J/ψ\to γA^0$

Using $J/ψ$ radiative decays from 9.0 billion $J/ψ$ events collected by the BESIII detector, we search for di-muon decays of a $CP$-odd light Higgs boson ($A^0$), predicted by many new physics models beyond the Standard Model, including the Next-to-Minimal Supersymmetric Standard Model. No evidence for the $CP$-odd light Higgs production is found, and we set $90\%$ confidence level upper limits on the product branching fraction $\mathcal{B}(J/ψ\to γA^0)\times \mathcal{B}(A^0 \to μ^+μ^-)$ in the range of $(1.2-778.0)\times 10^{-9}$ for $0.212 \le m_{A^0} \le 3.0$ GeV/$c^2$. The new measurement is a 6-7 times improvement over our previous measurement, and is also slightly better than the BaBar measurement in the low-mass region for $\tan β=1$.

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arXiv2022

Observation of the electromagnetic Dalitz decay $D^{\ast 0}\to D^{0}e^{+}e^{-}$

Based on 3.19 fb$^{-1}$ of $e^+e^-$ collision data accumulated at the center-of-mass energy 4.178 GeV with the BESIII detector operating at the BEPCII collider, the electromagnetic Dalitz decay $D^{\ast 0}\to D^{0}e^{+}e^{-}$ is observed for the first time with a statistical significance of $13.2σ$. The ratio of the branching fraction of $D^{\ast 0}\to D^{0}e^{+}e^{-}$ to that of $D^{\ast 0}\to D^{0} γ$ is measured to be $(11.08\pm0.76\pm0.49)\times 10^{-3}$. By using the world average value of the branching fraction of $D^{\ast 0}\to D^{0} γ$, the branching fraction of $D^{\ast 0}\to D^{0}e^{+}e^{-}$ is determined to be $(3.91\pm0.27\pm0.17\pm0.10)\times 10^{-3}$, where the first uncertainty is statistical, the second systematic and the third external branching fractions.

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arXiv2021

Observation of $J/ψ$ Electromagnetic Dalitz Decays to $X(1835)$, $X(2120)$ and $X(2370)$

Using a sample of about 10 billion $J/ψ$ events collected at a center-of-mass energy $\sqrt s = 3.097$ GeV with the BESIII detector, the electromagnetic Dalitz decays $J/ψ\to e^+e^- π^+ π^- η'$, with $η'\toγπ^+ π^-$ and $η'\toπ^+π^-η$, have been studied. The decay $J/ψ\to e^+ e^- X(1835)$ is observed with a significance of $15σ$, and the transition form factor of $J/ψ\to e^+e^-X(1835)$ is presented for the first time. The intermediate states $X(2120)$ and $X(2370)$ are also observed in the $π^+ π^- η'$ invariant mass spectrum with significances of $5.3σ$ and $7.3σ$. The corresponding product branching fractions for $J/ψ\to e^+e^-X$, $X\toπ^+π^-η'$ $(X=X(1835), X(2120)$ and $X(2370))$, are reported.

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arXiv2021

First measurement of polarizations in the decay $D^0 \to ωϕ$

Using a data sample corresponding to an integrated luminosity of 2.93 fb$^{-1}$ collected at a center-of-mass energy $\sqrt{s}=3.773$ GeV by the BESIII detector, the decay $D^0 \toωϕ$ is observed for the first time. The branching fraction is measured to be $(6.48 \pm 0.96 \pm 0.40)\times 10^{-4}$ with a significance of $6.3 σ$, where the first and second uncertainties are statistical and systematic, respectively. An angular analysis reveals that the $ϕ$ and $ω$ mesons from the $D^0 \to ωϕ$ decay are transversely polarized. The $95\%$ confidence level upper limit on longitudinal polarization fraction is set to be less than $0.24$, which is inconsistent with current theoretical expectations and challenges our understanding of the underlying dynamics in charm meson decays.

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arXiv2021

Cross section measurements of the $e^+e^-\to D^{+}D^{-}$ and $e^+e^-\to D^{*+}D^{-}$ processes at center-of-mass energies from 4.085 to 4.600 GeV

The Born cross sections of the $e^+e^-\to D^{*+}D^{*-}$ and $e^+e^-\to D^{*+}D^{-}$ processes are measured using $e^+e^-$ collision data collected with the BESIII experiment at center-of-mass energies from 4.085 to 4.600 GeV, corresponding to an integrated luminosity of $15.7~{\rm fb}^{-1}$. The results are consistent with and more precise than the previous measurements by the Belle, Babar and CLEO collaborations. The measurements are essential for understanding the nature of vector charmonium and charmonium-like states.

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arXiv2021

Measurement of the cross section for $e^{+}e^{-}\rightarrowΛ\barΛ$ and evidence of the decay $ψ(3770)\rightarrowΛ\barΛ$

The Born cross section of the process $e^{+}e^{-}\rightarrowΛ\barΛ$ is measured at 33 center-of-mass energies between 3.51 and 4.60 GeV using data corresponding to the total integrated luminosity of 20.0 fb$^{-1}$ collected with the BESIII detector at the BEPCII collider. Describing the energy dependence of the cross section requires a contribution from the $ψ(3770)\rightarrowΛ\barΛ$ decay, which is fitted with a significance of 4.6-4.9$σ$ including the systematic uncertainty. The lower bound on its branching fraction is $2.4\times10^{-6}$ at the 90% confidence level (C.L.), at least an order of magnitude larger than expected from predictions using a scaling based on observed electronic widths. This result indicates the importance of effects from vector charmonium(-like) states when interpreting data in terms of e.g., electromagnetic structure observables. The data do not allow for definite conclusions on the interplay with other vector charmonium(-like) states, and we set 90% C.L.upper limits for the products of their electronic widths and the branching fractions.

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arXiv2021

Study of the Dalitz decay $J/ψ\to e^+e^- η$

We report corrected results on a study of the electromagnetic Dalitz decay $J/ψ\to e^+e^- η$ and search for di-electron decays of a light dark gauge boson ($γ'$) in $J/ψ\to γ' η$ with the two $η$ decay modes $η\rightarrow γγ$ and $η\rightarrow π^+π^-π^0$, using $(1310.6\pm 7.0)\times10^6$ $J/ψ$ events collected with the BESIII detector. In particular we update the measurement of the pole mass of the transition form factor (TFF) of $J/ψ\to e^+e^- η$ to be $Λ= 2.56 \pm 0.04({\rm stat}) \pm 0.03({\rm syst})$ GeV/$c^2$. The branching fraction of $J/ψ\to e^+e^-η$ and the kinetic-mixing strength between the Standard Model photon and $γ'$ are also updated after taking the corrected $Λ$ value into account. The measured branching fraction of $J/ψ\to e^+e^- η$ is updated to be $(1.42 \pm 0.04({\rm stat}) \pm 0.07 ({\rm syst}))\times 10^{-5}$, where the first and second uncertainties are statistical and systematic, respectively.

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arXiv2021

Study of the decay $D_s^+\to K_S^0K_S^0π^+$ and observation an isovector partner to $f_0(1710)$

Using $e^+e^-$ annihilation data corresponding to a total integrated luminosity of 6.32 $\rm fb^{-1}$ collected at center-of-mass energies between 4.178 and 4.226 GeV with the BESIII detector, we perform an amplitude analysis of the decay $D_{s}^{+} \to K_{S}^{0}K_{S}^{0}π^{+}$ for the first time. An enhancement is observed in the $K_{S}^{0}K_{S}^{0}$ mass spectrum near 1.7 GeV/$c^2$, which was not seen in $D_{s}^{+} \to K^+K^-π^{+}$ in an earlier work, implying the existence of an isospin one partner of the $f_0(1710)$. The branching fraction of the decay $D_{s}^{+}\to K_{S}^{0}K_{S}^{0}π^{+}$ is determined to be $\mathcal{B}(D_{s}^{+} \to K_{S}^{0}K_{S}^{0}π^{+})=(0.68\pm0.04_{\rm stat}\pm0.01_{\rm syst})\%$.

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arXiv2021

Measurement of Branching Fractions of $J/ψ$ and $ψ(3686)$ decays to $Σ^{+}$ and $\overlineΣ^-$

Using $1310.6\times10^{6}$ $J/ψ$ and $448.1\times10^{6}$ $ψ(3686)$ events collected with the BESIII detector, the branching fractions of $J/ψ$ and $ψ(3686)$ decays to $Σ^{+}\overlineΣ^{-}$ are measured to be $(10.61 \pm 0.04 \pm 0.36) \times 10^{-4}$ and $(2.52 \pm 0.04 \pm 0.09) \times 10^{-4}$, respectively. In addition, the ratio of $\mathcal{B}(ψ(3686) \rightarrow Σ^{+}\overlineΣ^{-})/\mathcal{B}(J/ψ\rightarrow Σ^{+}\overlineΣ^{-})$ is determined to be $(23.8 \pm 1.1)\%$ which violates the "$12\%$ rule".

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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

Search for the hyperon semileptonic decay $Ξ^{-} \rightarrow Ξ^{0} e^{-} \bar{ν_{e}}$

Using $(10.087\pm0.044)\times10^{9}$ $J/ψ$ events collected by the BESIII detector at the BEPCII collider, we search for the hyperon semileptonic decay $Ξ^{-} \rightarrow Ξ^{0} e^{-} \barν_{e}$. No significant signal is observed and the upper limit on the branching fraction $\mathcal B(Ξ^{-} \rightarrow Ξ^{0} e^{-} \barν_{e})$ is set to be $2.59\times10^{-4}$ at 90 % confidence level. This result is one order of magnitude more strict than the previous best limit.

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arXiv2021

Observation of $ψ(3686)\toΞ(1530)^{0}\barΞ(1530)^{0}$ and $Ξ(1530)^{0}\barΞ^0$

Using $(448.1\pm2.9)\times 10^{6}$ $ψ(3686)$ events collected with the BESIII detector and a single-baryon tagging technique, we present the first observation of the decays $ψ(3686)\toΞ(1530)^{0}\barΞ(1530)^{0}$ and $Ξ(1530)^{0}\barΞ^0$. The branching fractions are measured to be ${\cal{B}}(ψ(3686)\toΞ(1530)^{0}\barΞ(1530)^{0}) = (6.77\pm0.14\pm0.39)\times10^{-5}$ and ${\cal{B}}(ψ(3686)\toΞ(1530)^{0}\barΞ^{0}) = (0.53\pm0.04\pm0.03)\times10^{-5}$. Here, the first and second uncertainties are statistical and systematic, respectively. In addition, the parameter associated with the angular distribution for the decay $ψ(3686)\toΞ(1530)^{0}\barΞ(1530)^0$ is determined to be $α= 0.32\pm0.19\pm0.07$, in agreement with theoretical predictions within one standard deviation.

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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 Branching Fraction of and Search for a CP-Violating Asymmetry in $η' \to π^+ π^- e^+ e^-$ at BESIII

The rare decay $η' \to π^+ π^- e^+ e^-$ is studied using a sample of $1.3 \times 10^9$ $J/ψ$ events collected with the BESIII detector at BEPCII in 2009 and 2012. The branching fraction is measured with improved precision to be $\left( 2.42\pm0.05_{stat.}\pm0.08_{syst.} \right) \times 10^{-3}$. Due to the inclusion of new data, this result supersedes the last BESIII result on this branching fraction. In addition, the CP-violating asymmetry in the angle between the decay planes of the $π^+π^-$-pair and the $e^+e^-$-pair is investigated. A measurable value would indicate physics beyond the standard model; the result is $\mathcal{A}_{CP} = \left(2.9\pm3.7_{stat.}\pm1.1_{syst.} \right)\%$, which is consistent with the standard model expectation of no CP-violation. The precision is comparable to the asymmetry measurement in the $K^0_L\toπ^+π^-e^+e^-$ decay where the observed $(14\pm2)\%$ effect is driven by a standard model mechanism.

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