Publications (299)498.47 Total impact
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ABSTRACT: Using 106×106 ψ′ events collected with the BESIII detector at the BEPCII storage ring, the higherorder multipole amplitudes in the radiative transition ψ′→γχc2→γπ+π/γK+K are measured. A fit to the χc2 production and decay angular distributions yields M2=0.046±0.010±0.013 and E3=0.015±0.008±0.018, where the first errors are statistical and the second systematic. Here M2 denotes the normalized magnetic quadrupole amplitude and E3 the normalized electric octupole amplitude. This measurement shows evidence for the existence of the M2 signal with 4.4σ statistical significance and is consistent with the charm quark having no anomalous magnetic moment.  [Show abstract] [Hide abstract]
ABSTRACT: We present results of a study of the decay J/ψ → ωηπ+ π using a sample of (225.2 ± 2.8) × 10(6) J/ψ events collected by the BESIII detector, and report the observation of a new process J/ψ → ωX(1870) with a statistical significance of 7.2σ, in which X(1870) decays to a(0)(±)(980)π±. Fitting to ηπ+ π mass spectrum yields a mass M = 1877.3 ± 6.3(stat)(7.4)(+3.4)(syst) MeV/c(2), a width Γ = 57 ± 12(stat)(4)(+19)(syst) MeV/c(2), and a product branching fraction B(J/ψ → ωX) × B(X→a(0)(±)(980)π±) × B(a(0) (±)(980) → ηπ±) = [1.50 ± 0.26(stat)(0.36)(+0.72) (syst)] × 10(4). Signals for J/ψ → ωf(1)(1285) and J/ψ → ω η(1405) are also clearly observed and measured.  [Show abstract] [Hide abstract]
ABSTRACT: The processes eta'(c) > rho(0)rho(0), K*0K*0, and phi phi are searched for using a sample of 1.06 x 10(8) psi' events collected with the BESIII detector at the BEPCII collider. No signals are observed in any of the three final states. The upper limits on the decay branching fractions are determined to be B(eta'(c) > rho(0)rho (0)) < 3.1 x 10(3), B(eta'(c) > K*0K*0) < 5.4 x 10(3), and B(eta'(c) > phi phi) < 2.0 x 10(3) at the 90% confidence level. The upper limits are lower than the existing theoretical predictions.  [Show abstract] [Hide abstract]
ABSTRACT: Using (106±4)×10⁻⁶ ψ(3686) events accumulated with the BESIII detector at the BEPCII e⁺e⁻ collider, we present the first measurement of decays of χ(c1) to vector meson pairs φφ, ωω, and ωφ. The branching fractions are measured to be (4.4±0.3±0.5)×10⁻⁴, (6.0±0.3±0.7)×10⁻⁴, and (2.2±0.6±0.2)×10⁻⁵, for χ(c1)→φφ, ωω, and ωφ, respectively, which indicates that the hadron helicity selection rule is significantly violated in χ(cJ) decays. In addition, the measurement of χ(cJ)→ωφ provides the first indication of the rate of doubly OZIsuppressed χ(cJ) decay. Finally, we present improved measurements for the branching fractions of χ(c0) and χ(c2) to vector meson pairs.  [Show abstract] [Hide abstract]
ABSTRACT: Using (106±4)×106 ψ(3686) events accumulated with the BESIII detector at the BEPCII e+e collider, we present the first measurement of decays of χc1 to vector meson pairs ÏÏ, ωω, and ωÏ. The branching fractions are measured to be (4.4±0.3±0.5)×104, (6.0±0.3±0.7)×104, and (2.2±0.6±0. 2)×105, for χc1→Ï Ï, ωω, and ωÏ, respectively, which indicates that the hadron helicity selection rule is significantly violated in χcJ decays. In addition, the measurement of χcJ→ωÏ provides the first indication of the rate of doubly OZIsuppressed χcJ decay. Finally, we present improved measurements for the branching fractions of χc0 and χc2 to vector meson pairs.  [Show abstract] [Hide abstract]
ABSTRACT: First measurements of the decays of the three χcJ states to pp̅ K+K final states are presented. Intermediate ϕ→K+K and Λ(1520)→pK resonance states are observed, and branching fractions for χcJ→p̅ K+Λ(1520), Λ(1520)Λ̅ (1520), and ϕpp̅ are reported. We also measure branching fractions for direct χcJ→pp̅ K+K decays. These are first observations of χcJ decays to unstable baryon resonances and provide useful information about the χcJ states. The experiment uses samples of χcJ mesons produced via radiative transitions from 106×106 ψ′ mesons collected in the BESIII detector at the BEPCII e+e collider.  [Show abstract] [Hide abstract]
ABSTRACT: The decays χcJ→γV (V=ϕ, ρ0, ω) are studied with a sample of radiative ψ′→γχcJ events in a sample of (1.06±0.04)×108ψ′ events collected with the BESIII detector. The branching fractions are determined to be: B(χc1→γϕ)=(25.8±5.2±2.3)×106, B(χc1→γρ0)=(228±13±22)×106, and B(χc1→γω)=(69.7±7.2±6.6)×106. The decay χc1→γϕ is observed for the first time. Upper limits at the 90% confidence level on the branching fractions for χc0 and χc2 decays into these final states are determined. In addition, the fractions of the transverse polarization component of the vector meson in χc1→γV decays are measured to be 0.290.120.09+0.13+0.10 for χc1→γϕ, 0.158±0.0340.014+0.015 for χc1→γρ0, and 0.2470.0870.026+0.090+0.044 for χc1→γω, respectively. The first errors are statistical and the second ones are systematic. 
Article: Study of a00(980)f0(980) mixing
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ABSTRACT: Using samples of 2.25×108 J/ψ events and 1.06×108 ψ′ events collected with the BES III detector, we study the f0(980)→a00(980) and a00(980)→f0(980) transitions in the processes J/ψ→ϕf0(980)→ϕa00(980) and χc1→π0a00(980)→π0f0(980), respectively. Evidence for f0(980)→a00(980) is found with a significance of 3.4σ, while in the case of a00(980)→f0(980) transition, the significance is 1.9σ. Measurements and upper limits of both branching ratios and mixing intensities are determined. 
Article: Confirmation of the X(1835) and observation of the resonances X(2120) and X(2370) in J/ψ→γπ+πη'.
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ABSTRACT: With a sample of (225.2±2.8)×10(6) J/ψ events registered in the BESIII detector, J/ψ→γπ(+)π()η(') is studied using two η(') decay modes: η(')→π(+)π()η and η(')→γρ(0). The X(1835), which was previously observed by BESII, is confirmed with a statistical significance that is larger than 20σ. In addition, in the π(+)π()η(') invariantmass spectrum, the X(2120) and the X(2370), are observed with statistical significances larger than 7.2σ and 6.4σ, respectively. For the X(1835), the angular distribution of the radiative photon is consistent with expectations for a pseudoscalar.  [Show abstract] [Hide abstract]
ABSTRACT: We present a study of the Pwave spintriplet charmonium χcJ decays (J=0, 1, 2) into π0π0π0π0. The analysis is based on 106×106 ψ′ decays recorded with the BESIII detector at the BEPCII electron positron collider. The decay into the π0π0π0π0 hadronic final state is observed for the first time. We measure the branching fractions B(χc0→π0π0π0π0)=(3.34±0.06±0.44)×103, B(χc1→π0π0π0π0)=(0.57±0.03±0.08)×103, and B(χc2→π0π0π0π0)=(1.21±0.05±0.16)×103, where the uncertainties are statistical and systematical, respectively.  [Show abstract] [Hide abstract]
ABSTRACT: The Dalitz plot of η′→ηπ+π decay is studied using (225.2±2.8)×106 J/ψ events collected with the BESIII detector at the BEPCII e+e collider. With the largest sample of η′ decays to date, the parameters of the Dalitz plot are determined in a generalized and a linear representation. Also, the branching fraction of J/ψ→γη′ is determined to be (4.84±0.03±0.24)×103, where the first error is statistical and the second systematic.  [Show abstract] [Hide abstract]
ABSTRACT: The Dalitz plot of eta'>etapi+pi decay is studied using (225.2±2.8)×106 J/psi events collected with the BESIII detector at the BEPCII e+e collider. With the largest sample of eta' decays to date, the parameters of the Dalitz plot are determined in a generalized and a linear representation. Also, the branching fraction of J/psi>gammaeta' is determined to be (4.84±0.03±0.24)×103, where the first error is statistical and the second systematic.  [Show abstract] [Hide abstract]
ABSTRACT: We present a study of the Pwave spintriplet charmonium chicJ decays (J=0, 1, 2) into pi0pi0pi0pi0. The analysis is based on 106×106 psi' decays recorded with the BESIII detector at the BEPCII electron positron collider. The decay into the pi0pi0pi0pi0 hadronic final state is observed for the first time. We measure the branching fractions B(chic0>pi0pi0pi0pi0)=(3.34±0.06±0.44)×103, B(chic1>pi0pi0pi0pi0)=(0.57±0.03±0.08)×103, and B(chic2>pi0pi0pi0pi0)=(1.21±0.05±0.16)×103, where the uncertainties are statistical and systematical, respectively.  [Show abstract] [Hide abstract]
ABSTRACT: We present results of a study of the decay J/psi>omegaetapi+pi using a sample of (225.2±2.8)×106 J/psi events collected by the BESIII detector, and report the observation of a new process J/psi>omegaX(1870) with a statistical significance of 7.2sigma, in which X(1870) decays to a0±(980)pi/+. Fitting to etapi+pi mass spectrum yields a mass M=1877.3±6.3(stat)7.4+3.4(syst)MeV/c2, a width Gamma=57±12(stat)4+19(syst)MeV/c2, and a product branching fraction B(J/psi>omegaX)×B(X>a0±(980)pi/+)×B(a0±(980)>etapi±)=[1.50±0.26(stat)0.36+0.72(syst)]×104. Signals for J/psi>omegaf1(1285) and J/psi>omegaeta(1405) are also clearly observed and measured. 
Article: Observation of chic1 Decays into Vector Meson Pairs varphivarphi, omegaomega, and omegavarphi
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ABSTRACT: Using (106±4)×106 psi(3686) events accumulated with the BESIII detector at the BEPCII e+e collider, we present the first measurement of decays of chic1 to vector meson pairs varphivarphi, omegaomega, and omegavarphi. The branching fractions are measured to be (4.4±0.3±0.5)×104, (6.0±0.3±0.7)×104, and (2.2±0.6±0.2)×105, for chic1>varphivarphi, omegaomega, and omegavarphi, respectively, which indicates that the hadron helicity selection rule is significantly violated in chicJ decays. In addition, the measurement of chicJ>omegavarphi provides the first indication of the rate of doubly OZIsuppressed chicJ decay. Finally, we present improved measurements for the branching fractions of chic0 and chic2 to vector meson pairs.  [Show abstract] [Hide abstract]
ABSTRACT: The decays ψ⊃′→γπ0, γη and γη⊃′ are studied using data collected with the BESIII detector at the BEPCII e⊃+e⊃ collider. The processes ψ⊃′→γπ0 and ψ⊃′→γη are observed for the first time with signal significances of 4.6σ and 4.3σ, respectively. The branching fractions are determined to be B(ψ⊃′→γπ0)=(1.58±0.40±0.13) ×10⊃6, B(ψ⊃′→γη)=(1.38±0. 48±0.09)×10⊃6, and B(ψ⊃′→γη⊃ ′)=(126±3±8)×10⊃6, where the first errors are statistical and the second ones systematic.  [Show abstract] [Hide abstract]
ABSTRACT: The decays ψ'→γπ(0), γη and γη' are studied using data collected with the BESIII detector at the BEPCII e(+)e() collider. The processes ψ'→γπ(0) and ψ'→γη are observed for the first time with signal significances of 4.6σ and 4.3σ, respectively. The branching fractions are determined to be B(ψ'→γπ(0))=(1.58±0.40±0.13)×10(6), B(ψ'→γη)=(1.38±0.48±0.09)×10(6), and B(ψ'→γη')=(126±3±8)×10(6), where the first errors are statistical and the second ones systematic.  [Show abstract] [Hide abstract]
ABSTRACT: The decays psi'>gammapi0, gammaeta and gammaeta' are studied using data collected with the BESIII detector at the BEPCII e+e collider. The processes psi'>gammapi0 and psi'>gammaeta are observed for the first time with signal significances of 4.6sigma and 4.3sigma, respectively. The branching fractions are determined to be B(psi'>gammapi0)=(1.58±0.40±0.13)×106, B(psi'>gammaeta)=(1.38±0.48±0.09)×106, and B(psi'>gammaeta')=(126±3±8)×106, where the first errors are statistical and the second ones systematic.  [Show abstract] [Hide abstract]
ABSTRACT: Unexpected features of the BaBar data on e +e \( \rightarrow\) B \( \overline{{B}}\) crosssections (B stands for baryon) are discussed. These data have been collected, with unprecedented accuracy, by means of the initialstate radiation technique, which is particularly suitable in giving good acceptance and energy resolution at threshold. A striking feature observed in the BaBar data is the nonvanishing crosssection at threshold for all these processes. This is the expectation due to the Coulomb enhancement factor acting on a charged fermion pair. In the case of e +e \( \rightarrow\) p \( \overline{{p}}\) it is found that Coulomb finalstate interactions largely dominate the crosssection and the form factor is  G p(4M 2p) ∼ 1 , which could be a general feature for baryons. In the case of neutral baryons an interpretation of the nonvanishing crosssection at threshold is suggested, based on quark electromagnetic interaction and taking into account the asymmetry between attractive and repulsive Coulomb factors. Besides strange baryon crosssections are compared to U spin invariance predictions. 
Article: Pointlike Baryons?
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ABSTRACT: A peculiar feature, observed in the BaBar data on e+e > baryonantibaryon cross sections, is the nonvanishing cross section at threshold for all these processes. This is the expectation due to the Coulomb enhancement factor acting on a charged fermion pair. Remarkably, in the case of e+e > ppbar it is found that Coulomb final state interactions largely dominate the cross section at threshold and it turns out a form factor G(4Mp^2)~1, as a pointlike fermion. Also in the case of e+e > Lambda_cantiLambda_c, as recently measured by Belle for the first time, a pointlike behavior is suggested for the charmed charged baryon, being the Lambda_c form factor at threshold G~1, even if within a large error. In the case of neutral strange baryons the nonvanishing cross section at threshold is interpreted as a remnant of quark pair Coulomb interaction before the hadronization, taking into account the asymmetry between attractive and repulsive Coulomb factors. Besides strange baryon cross sections are successfully compared to Uspin invariance relationships.
Publication Stats
4k  Citations  
498.47  Total Impact Points  
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Institutions

2011

Institute of physics china
Peping, Beijing, China


2010

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


2003

Scuola Normale Superiore di Pisa
Pisa, Tuscany, Italy


2002

University of Naples Federico II
 Department of Physical Sciences
Napoli, Campania, Italy


1993

Harvard University
Cambridge, Massachusetts, United States


19901993

Universität Siegen
Siegen, North RhineWestphalia, Germany 
University of Florence
Florens, Tuscany, Italy


1992

Lancaster University
 Department of Physics
Lancaster, ENG, United Kingdom


19881990

Université ParisSud 11
Orsay, ÎledeFrance, France


19831990

INFN  Istituto Nazionale di Fisica Nucleare
Frascati, Latium, Italy


1987

University of Padova
Padua, Veneto, Italy
