Publications (50)94.83 Total impact
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ABSTRACT: Based on 106×10^{6}ψ(3686) events collected with the BESIII detector at the BEPCII facility, a partial wave analysis of ψ(3686)→pp[over ¯]π^{0} is performed. The branching fraction of this channel has been determined to be B(ψ(3686)→pp[over ¯]π^{0})=(1.65±0.03±0.15)×10^{4}. In this decay, 7 N^{*} intermediate resonances are observed. Among these, two new resonances, N(2300) and N(2570) are significant, one 1/2^{+} resonance with a mass of 2300_{300}^{+40+109} MeV/c^{2} and width of 340_{3058}^{+30+110} MeV/c^{2}, and one 5/2^{} resonance with a mass of 2570_{1010}^{+19+34} MeV/c^{2} and width of 250_{2421}^{+14+69} MeV/c^{2}. For the remaining 5 N^{*} intermediate resonances [N(1440), N(1520), N(1535), N(1650) and N(1720)], the analysis yields mass and width values that are consistent with those from established resonances.Physical Review Letters 01/2013; 110(2):022001. · 7.94 Impact Factor  [show abstract] [hide abstract]
ABSTRACT: The twophoton transition ψ(3686)→γγJ/ψ is studied in a sample of 1.06×10^{8} ψ(3686) decays collected by the BESIII detector. The branching fraction is measured to be (3.1±0.6(stat)_{1.0}^{+0.8}(syst))×10^{4} using J/ψ→e^{+}e^{} and J/ψ→μ^{+}μ^{} decays, and its upper limit is estimated to be 4.5×10^{4} at the 90% confidence level. This work represents the first measurement of a twophoton transition among charmonium states. The orientation of the ψ(3686) decay plane and the J/ψ polarization in this decay are also studied. In addition, the product branching fractions of sequential E1 transitions ψ(3686)→γχ_{cJ} and χ_{cJ}→γJ/ψ(J=0,1,2) are reported.Physical Review Letters 10/2012; 109(17):172002. · 7.94 Impact Factor  [show abstract] [hide abstract]
ABSTRACT: The number of J/ψ events collected with the BESIII detector at the BEPCII from June 12 to July 28, 2009 is determined to be (225.3±2.8) × 106 using J/ψ →inclusive events, where the uncertainty is the systematic error and the statistical one is negligible.Chinese Physics C 10/2012; 36(10):915. · 0.34 Impact Factor  [show abstract] [hide abstract]
ABSTRACT: Decays of the χcJ states (J=0, 1, 2) to ΛΛ̅ π+π, including processes with intermediate Σ(1385), are studied through the E1 transition ψ′→γχcJ using 106×106 ψ′ events collected with the BESIII detector at BEPCII. This is the first observation of χcJ decays to the final state ΛΛ̅ π+π. The branching ratio of the intermediate process χcJ→Σ(1385)±Σ̅ (1385)∓ is also measured for the first time, and the results agree with the theoretical predictions based on the coloroctet effect.Phys. Rev. D. 09/2012; 86(5). 
Article: Study of J/ψ→pp̅ and J/ψ→nn̅
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ABSTRACT: The decays J/ψ→pp̅ and J/ψ→nn̅ have been investigated with a sample of 225.2×106 J/ψ events collected with the BESIII detector at the BEPCII e+e collider. The branching fractions are determined to be B(J/ψ→pp̅ )=(2.112±0.004±0.031)×103 and B(J/ψ→nn̅ )=(2.07±0.01±0.17)×103. Distributions of the angle θ between the proton or antineutron and the beam direction are well described by the form 1+αcos2θ, and we find α=0.595±0.012±0.015 for J/ψ→pp̅ and α=0.50±0.04±0.21 for J/ψ→nn̅ . Our branchingfraction results suggest a large phase angle between the strong and electromagnetic amplitudes describing the J/ψ→NN̅ decay.Phys. Rev. D. 08/2012; 86(3).  [show abstract] [hide abstract]
ABSTRACT: Hadronic transitions of $\chi_{cJ}\to \eta_{c}\pi^{+}\pi^{}$ (J=0, 1, 2) are searched for using a sample of $1.06\times 10^{8}$ $\psi(3686)$ events collected with the BESIII detector at the BEPCII storage ring. The $\etac$ is reconstructed with $K_{S}^{0}K^{+}\pi^{}+c.c.$ and $K^{+}K^{}\pi^{0}$ final states. No signals are observed in any of the three $\chi_{cJ}$ states in either $\etac$ decay mode. At the 90% confidence level, the upper limits are determined to be $\BR(\chi_{c0}\to \eta_{c}\pi^{+}\pi^{})<0.07%$, $\BR(\chi_{c1}\to \eta_{c}\pi^{+}\pi^{})<0.32%$, and $\BR(\chi_{c2}\to \eta_{c}\pi^{+}\pi^{})<0.54%$. The upper limit of $\BR(\chi_{c1}\to \eta_{c}\pi^{+}\pi^{}$ is lower than the existing theoretical prediction by almost an order of magnitude. The branching fractions of $\chi_{cJ}\to K_{S}^{0}K^{+}\pi^{}\pi^{+}\pi^{}+c.c.$, $K^{+}K^{}\pi^{+}\pi^{}\pi^{0}$, $\omega K^{+}K^{}$ and $\phi\pi^{+}\pi^{}\pi^{0}$ (J=0, 1, 2) are measured for the first time.08/2012;  [show abstract] [hide abstract]
ABSTRACT: Using $(106\pm4)\times 10^6$ $\psip$ events accumulated with the BESIII detector at the BEPCII $e^+e^$ collider, we present measurements of the branching fractions for psi' decays to $K^{+}K^{}\pi^{0}$ and $K^{+}K^{}\eta$. In these final states, the decay $\psi'\to K_2^{*}(1430)^+K^+c.c.$ is observed for the first time, and its branching fraction is measured to be $(7.12\pm{0.62}{\rm (stat.)}^{+1.13}_{0.61}{\rm (syst.)})\times 10^{5}$, which indicates a violation of the helicity selection rule in $\psip$ decays. The branching fractions of $\psi'\to K^*(892)^+K^+c.c., \phi\eta, \phi\pi^0$ are also measured. The measurements are used to test the QCD predictions on charmonium decays.08/2012;  [show abstract] [hide abstract]
ABSTRACT: Using a 478 pb$^{1}$ data sample collected with the BESIII detector operating at the BEPCII storage ring at a centerofmass energy of $\sqrt{s}=4.009$ GeV, the production of $e^{+}e^{}\to \eta J\psi$ is observed for the first time with a statistical significance of greater than $10\sigma$. The Born cross section is measured to be $(32.1\pm 2.8 \pm 1.3)$ pb, where the first error is statistical and the second systematic. Assuming the $\eta J\psi$ signal is from a hadronic transition of the $\psi(4040)$, the fractional transition rate is determined to be ${\cal B}(\psi(4040)\to \eta J\psi)=(5.2\pm 0.5\pm 0.2\pm 0.5)\times 10^{3}$, where the first, second, and third errors are statistical, systematic, and the uncertainty from the $\psi(4040)$ resonant parameters, respectively. The production of $e^{+}e^{} \to \pi^0 J\psi$ is searched for, but no significant signal is observed, and ${\cal B}(\psi(4040)\to \pi^0 J\psi) < 2.8 \times 10^{4}$ is obtained at the 90% confidence level.08/2012; 
Article: Evidence for $\eta_{c} \rightarrow \gamma\gamma$ and Measurement of $J/\psi\rightarrow 3\gamma$
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ABSTRACT: The decay of $J/\psi$ to three photons is studied using $\psi(3686)\to\pi^+\pi^J/\psi$ in a sample of $1.0641\times10^8$ $\psi(3686)$ events collected with the BESIII detector. Evidence of the direct decay of $\eta_c$ to two photons, $\eta_c\to\gamma\gamma$, is reported, and the product branching fraction is determined to be $\mathcal{B}(J/\psi\to\gamma\eta_c,\eta_c\to \gamma\gamma)=(4.5\pm1.2\pm0.6)\times10^{6}$, where the first error is statistical and the second is systematic. The branching fraction for $J/\psi\to3\gamma$ is measured to be $(11.3\pm1.8\pm2.0)\times 10^{6}$ with improved precision.08/2012;  [show abstract] [hide abstract]
ABSTRACT: Decays of the chi_{cJ} states (J=0,\ 1,\ 2) to \Lambda \Lambda bar\ pi^{+} \pi^{}, including processes with intermediate \Sigma(1385), are studied through the E1 transition psi'>\gamma chi_{cJ} using 106 million psi' events collected with the BESIII detector at BEPCII. This is the first observation of chi_{cJ} decays to the final state \Lambda\Lambda bar \pi^{+}\pi^{}. The branching ratio of the intermediate process chi_{cJ}>\Sigma(1385)^{+/} \bar{\Sigma}(1385)^{/+} is also measured for the first time, and the results agree with the theoretical predictions based on the coloroctet effect.07/2012; 
Article: First observation of the isospin violating decay $J/\psi\rightarrow \Lambda\bar{\Sigma}^{0}+c.c.$
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ABSTRACT: Using a sample of $(225.2\pm 2.8)\times 10^6$ $J/\psi$ events collected with the BESIII detector, we present results of a study of $J/\psi\rightarrow \gamma\Lambda\bar{\Lambda}$ and report the first observation of the isospin violating decay $J/\psi\rightarrow\Lambda\bar{\Sigma}^{0}+c.c.$, in which $\bar{\Sigma}^{0}$ decays to $\gamma \bar{\Lambda}$. The measured branching fractions are $\mathcal{B}(J/\psi\rightarrow\bar{\Lambda}\Sigma^{0}$) = $(1.46\pm0.11\pm0.12) \times10^{5}$ and $\mathcal{B}(J/\psi\rightarrow\Lambda\bar{\Sigma^{0}}$) = $(1.37\pm0.12\pm0.11) \times10^{5}$. We search for $\Lambda(1520) \rightarrow \gamma \Lambda$ decay, and find no evident signal, and an upper limit for the product branching fraction $\mathcal{B}(J/\psi\rightarrow\Lambda\bar{\Lambda}(1520)+c.c.)\times \mathcal{B}(\Lambda(1520)\rightarrow\gamma\Lambda)<4.1 \times10^{6}$ is set at the 90% confidence level. We also report the observation of $\eta_{c}\rightarrow\Lambda\bar{\Lambda}$ in $J/\psi \rightarrow \gamma \eta_{c}$, $\eta_{c}\rightarrow\Lambda\bar{\Lambda}$ and measure the branching fraction $\mathcal{B}(\eta_{c}\rightarrow\Lambda\bar{\Lambda}) =(1.16\pm0.12 (stat)\pm0.19(syst)\pm0.28(PDG))\times10^{3}$.07/2012;  [show abstract] [hide abstract]
ABSTRACT: Based on a data sample of 106×106 ψ′ events collected with the BESIII detector, the decays ψ′→γχc0,2, χc0,2→γγ are studied to determine the twophoton widths of the χc0,2 states. The twophoton decay branching fractions are determined to be B(χc0→γγ)=(2.24±0.19±0.12±0.08)×104 and B(χc2→γγ)=(3.21±0.18±0.17±0.13)×104. From these, the twophoton widths are determined to be Γγγ(χc0)=(2.33±0.20±0.13±0.17) keV, Γγγ(χc2)=(0.63±0.04±0.04±0.04) keV, and R=Γγγ(χc2)/Γγγ(χc0)=0.271±0.029±0.013±0.027, where the uncertainties are statistical, systematic, and those from the PDG B(ψ′→γχc0,2) and Γ(χc0,2) errors, respectively. The ratio of the twophoton widths for helicity λ=0 and helicity λ=2 components in the decay χc2→γγ is measured for the first time to be f0/2=Γγγλ=0(χc2)/Γγγλ=2(χc2)=0.00±0.02±0.02.Phys. Rev. D. 06/2012; 85(11).  [show abstract] [hide abstract]
ABSTRACT: Using a sample of 106 million \psi(3686) events collected with the BESIII detector at the BEPCII storage ring, we have made the first measurement of the M1 transition between the radially excited charmonium Swave spintriplet and the radially excited Swave spinsinglet states: \psi(3686)\to\gamma\eta_c(2S). Analyses of the processes \psi(2S)\to \gamma\eta_c(2S) with \eta_c(2S)\to \K_S^0 K\pi and K^+K^\pi^0 gave an \eta_c(2S) signal with a statistical significance of greater than 10 standard deviations under a wide range of assumptions about the signal and background properties. The data are used to obtain measurements of the \eta_c(2S) mass (M(\eta_c(2S))=3637.6\pm 2.9_\mathrm{stat}\pm 1.6_\mathrm{sys} MeV/c^2), width (\Gamma(\eta_c(2S))=16.9\pm 6.4_\mathrm{stat}\pm 4.8_\mathrm{sys} MeV), and the product branching fraction (\BR(\psi(3686)\to \gamma\eta_c(2S))\times \BR(\eta_c(2S)\to K\bar K\pi) = (1.30\pm 0.20_\mathrm{stat}\pm 0.30_\mathrm{sys})\times 10^{5}). Combining our result with a BaBar measurement of \BR(\eta_c(2S)\to K\bar K \pi), we find the branching fraction of the M1 transition to be \BR(\psi(3686)\to\gamma\eta_c(2S)) = (6.8\pm 1.1_\mathrm{stat}\pm 4.5_\mathrm{sys})\times 10^{4}.05/2012; 
Article: Twophoton widths of the $\chi_{c0, 2}$ states and helicity analysis for $\chi_{c2}\ar\gamma\gamma$}
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ABSTRACT: Based on a data sample of 106 M $\psi^{\prime}$ events collected with the BESIII detector, the decays $\psi^{\prime}\ar\gamma\chi_{c0, 2}$,$\chi_{c0, 2}\ar\gamma\gamma$ are studied to determine the twophoton widths of the $\chi_{c0, 2}$ states. The twophoton decay branching fractions are determined to be ${\cal B}(\chi_{c0}\ar\gamma\gamma) = (2.24\pm 0.19\pm 0.12\pm 0.08)\times 10^{4}$ and ${\cal B}(\chi_{c2}\ar\gamma\gamma) = (3.21\pm 0.18\pm 0.17\pm 0.13)\times 10^{4}$. From these, the twophoton widths are determined to be $\Gamma_{\gamma \gamma}(\chi_{c0}) = (2.33\pm0.20\pm0.13\pm0.17)$ keV, $\Gamma_{\gamma \gamma}(\chi_{c2}) = (0.63\pm0.04\pm0.04\pm0.04)$ keV, and $\cal R$ $=\Gamma_{\gamma \gamma}(\chi_{c2})/\Gamma_{\gamma \gamma}(\chi_{c0})=0.271\pm 0.029\pm 0.013\pm 0.027$, where the uncertainties are statistical, systematic, and those from the PDG ${\cal B}(\psi^{\prime}\ar\gamma\chi_{c0,2})$ and $\Gamma(\chi_{c0,2})$ errors, respectively. The ratio of the twophoton widths for helicity $\lambda=0$ and helicity $\lambda=2$ components in the decay $\chi_{c2}\ar\gamma\gamma$ is measured for the first time to be $f_{0/2} =\Gamma^{\lambda=0}_{\gamma\gamma}(\chi_{c2})/\Gamma^{\lambda=2}_{\gamma\gamma}(\chi_{c2}) = 0.00\pm0.02\pm0.02$.05/2012;  [show abstract] [hide abstract]
ABSTRACT: Using a data sample containing 1.06×108 ψ′ events collected with the BESIII detector at the BEPCII electronpositron collider, we search for a light exotic particle X in the process ψ′→π+πJ/ψ, J/ψ→γX, X→μ+μ. This light particle X could be a Higgslike boson A0, a spin1 U boson, or a pseudoscalar sgoldstino particle. In this analysis, we find no evidence for any μ+μ mass peak between the mass threshold and 3.0 GeV/c2. We set 90%confidencelevel upper limits on the productbranching fractions for J/ψ→γA0, A0→μ+μ which range from 4×107 to 2.1×105, depending on the mass of A0, for M(A0)<3.0 GeV/c2. Only one event is seen in the mass region below 255 MeV/c2, and this has a μ+μ mass of 213.3 MeV/c2 and the productbranchingfraction upper limit 5×107.Phys. Rev. D. 05/2012; 85(9).  [show abstract] [hide abstract]
ABSTRACT: The decays J/ψ → γ π+ π π0 and J/ψ → γ π0 π0 π0 are analyzed using a sample of 225×10(6) J/ψ events collected with the BESIII detector. The decay of η(1405) → f(0)(980)π0 with a large isospin violation is observed for the first time. The width of the f(0)(980) observed in the dipion mass spectra is anomalously narrower than the world average. Decay rates for threepion decays of the η' are also measured precisely.Physical Review Letters 05/2012; 108(18):182001. · 7.94 Impact Factor  [show abstract] [hide abstract]
ABSTRACT: The decays $J/\psi\to p\bar{p}$ and $J/\psi\to n\bar{n}$ have been investigated with a sample of 225.2 million $J/\psi$ events collected with the BESIII detector at the BEPCII $e^+e^$ collider. The branching fractions are determined to be $\mathcal{B}(J/\psi\to p\bar{p})=(2.112\pm0.004\pm0.031)\times10^{3}$ and $\mathcal{B}(J/\psi\to n\bar{n})=(2.07\pm0.01\pm0.17)\times10^{3}$. Distributions of the angle $\theta$ between the proton or antineutron and the beam direction are well described by the form $1+\alpha\cos^2\theta$, and we find $\alpha=0.595\pm0.012\pm0.015$ for $J/\psi\to p\bar{p}$ and $\alpha=0.50\pm0.04\pm0.21$ for $J/\psi\to n\bar{n}$. Our branchingfraction results suggest a large phase angle between the strong and electromagnetic amplitudes describing the $J/\psi\to N\bar{N}$ decay.05/2012;  [show abstract] [hide abstract]
ABSTRACT: The twophoton transition $\psi(3686)\to\gamma\gamma J/\psi$ is studied in a sample of 106 million $\psi(3686)$ decays collected by the BESIII detector. The branching fraction is measured to be $(3.1\pm0.6(\unit{stat})^{+0.8}_{1.0}(\unit{syst})) \times10^{4}$ using $J/\psi\to e^+e^$ and $J/\psi\to\mu^+\mu^$ decays, and its upper limit is estimated to be $4.5\times10^{4}$ at the 90% conference level. This work represents the first measurement of a twophoton transition among charmonium states. The orientation of the $\psi(3686)$ decay plane and the $J/\psi$ polarization in this decay are also studied. In addition, the product branching fractions of sequential $E1$ transitions $\psi(3686)\to\gamma\chi_{cJ}, \chi_{cJ}\to\gamma J/\psi (J=0,1,2)$ are reported.04/2012;  [show abstract] [hide abstract]
ABSTRACT: A partial wave analysis of the pp¯ massthreshold enhancement in the reaction J/ψ→γpp¯ is used to determine its J(PC) quantum numbers to be 0(+), its peak mass to be below threshold at M=1832(5)(+19)(stat)(17)(+18)(syst)±19(model) MeV/c(2), and its total width to be Γ<76 MeV/c(2) at the 90% C.L. The product of branching ratios is measured to be BR[J/ψ→γX(pp¯)]BR[X(pp¯)→pp¯]=[9.0(1.1)(+0.4)(stat)(5.0)(+1.5)(syst)±2.3(model)]×10(5). A similar analysis performed on ψ(3686)→γpp¯ decays shows, for the first time, the presence of a corresponding enhancement with a production rate relative to that for J/ψ decays of R=[5.08(0.45)(+0.71)(stat)(3.58)(+0.67)(syst)±0.12(model)]%.Physical Review Letters 03/2012; 108(11):112003. · 7.94 Impact Factor 
Article: Precision measurement of the branching fractions of J/psi > pi+pipi0 and psi' > pi+pipi0
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ABSTRACT: We study the decays of the J/psi and psi' mesons to pi+pipi0 using data samples at both resonances collected with the BES III detector in 2009. We measure the corresponding branching fractions with unprecedented precision and provide mass spectra and Dalitz plots. The branching fraction for J/psi > pi+pipi0 is determined to be (2.137 + 0.004 (stat.) +0.0580.056 (syst.) +0.0270.026 (norm.))*102, and the branching fraction for psi' > pi+pipi0 is measured as (2.14 + 0.03 (stat.) +0.080.07 (syst.) +0.090.08 (norm.))*104. The J/psi decay is found to be dominated by an intermediate rho(770) state, whereas the psi' decay is dominated by dipion masses around 2.2 GeV/c2, leading to strikingly different Dalitz distributions.02/2012;
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Institutions

2012

RuhrUniversität Bochum
Bochum, North RhineWestphalia, Germany


2011

Institute of physics china
Peping, Beijing, China


2010

Government of the People's Republic of China
Peping, Beijing, China
