Publications (984)3234.66 Total impact

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ABSTRACT: We report the observation of the $X(3823)$ in the process $e^+e^\to \pi^+\pi^X(3823) \to \pi^+\pi^\gamma\chi_{c1}$ with a statistical significance of $6.2\sigma$, in data samples at centerofmass energies $\sqrt{s}=$4.230, 4.260, 4.360, 4.420 and 4.600~GeV collected with the BESIII detector at the BEPCII electron positron collider. The measured mass of the $X(3823)$ is $(3821.7\pm 1.3\pm 0.7)$~MeV/$c^2$, where the first error is statistical and the second systematic, and the width is less than $16$~MeV at the 90\% confidence level. The products of the Born cross sections for $e^+e^\to \pi^+\pi^X(3823)$ and the branching ratio $\mathcal{B}[X(3823)\to \gamma\chi_{c1,c2}]$ are also measured. These measurements are in good agreement with the assignment of the $X(3823)$ as the $\psi(1^3D_2)$ charmonium state. 
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ABSTRACT: Using data samples collected with the BESIII detector operating at the BEPCII collider at centerofmass energies from 3.810 to 4.600 GeV, we perform a study of $e^{+}e^{} \to \eta J/\psi$ and $\pi^0 J/\psi$. Statistically significant signals of $e^{+}e^{} \to \eta J/\psi$ are observed at $\sqrt{s}$ = 4.190, 4.210, 4.220, 4.230, 4.245, 4.260, 4.360 and 4.420 GeV, while no signals of $e^{+}e^{} \to \pi^{0} J/\psi$ are observed. The measured energydependent Born cross section for $e^{+}e^{} \to \eta J/\psi$ shows an enhancement around 4.2~GeV. The measurement is compatible with an earlier measurement by Belle, but with a significantly improved precision. 
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ABSTRACT: Using a data sample of 106 million $\psi(3686)$ events collected with the BESIII detector operated at the BEPCII storage ring, we study for the first time the decay $\chi_{cJ}\to\phi K^{0}_S K^{\pm}\pi^{\mp}$ and $\chi_{cJ}\to\phi K^{+} K^{}\pi^{0}$ in the E1 radiative transition $\psi(3686)\to\gamma\chi_{cJ}$. The decays are dominated by the threebody decay $\chi_{cJ}\to \phi K^*(892)\bar{K}$. We measure branching fractions for this reaction via the neutral and charged $K^*(892)$ and find them consistent with each other within the expectation of isospin symmetry. In the $K\bar{K}\pi$ invariant mass distribution a structure near the $K^*(892)\bar{K}$ mass threshold is observed, and the corresponding mass and width are measured to be $1412\pm4(\mathrm{stat.})\pm8(\mathrm{sys.}) \mathrm{MeV}/c^2$ and $\Gamma$ = $84\pm12(\mathrm{stat.})\pm40(\mathrm{sys.}) \mathrm{MeV}$, respectively. The observed state favors an assignment to the $h_1(1380)$, considering its possible $J^{PC}$ and comparing its mass, width and decay mode to those reported in the Particle Data Group. 
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ABSTRACT: From December 2011 to May 2014, about 5 $\rm fb^{1}$ of data were taken with the BESIII detector at centerofmass energies between 3.810 GeV and 4.600 GeV to study the charmoniumlike states and higher excited charmonium states. The time integrated luminosity of the collected data sample is measured to a precision of 1% by analyzing events produced by the largeangle Bhabha scattering process. 
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ABSTRACT: Based on data samples collected with the BESIII detector at the BEPCII collider at nine center of mass energies from 4.21 to 4.42 GeV, we search for the production of e^{+}e^{}→ωχ_{cJ} (J=0, 1, 2). The process e^{+}e^{}→ωχ_{c0} is observed for the first time, and the Born cross sections at sqrt[s]=4.23 and 4.26 GeV are measured to be (55.4±6.0±5.9) and (23.7±5.3±3.5) pb, respectively, where the first uncertainties are statistical and the second are systematic. The ωχ_{c0} signals at the other seven energies and the e^{+}e^{}→ωχ_{c1} and ωχ_{c2} signals are not significant, and the upper limits on the cross sections are determined. By examining the ωχ_{c0} cross section as a function of center of mass energy, we find that it is inconsistent with the line shape of the Y(4260) observed in e^{+}e^{}→π^{+}π^{}J/ψ. Assuming the ωχ_{c0} signals come from a single resonance, we extract the mass and width of the resonance to be (4230±8±6) MeV/c^{2} and (38±12±2) MeV, respectively, and the statistical significance is more than 9σ.Physical Review Letters 03/2015; 114(9):092003. · 7.73 Impact Factor 
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ABSTRACT: We present a measurement of the asymmetry A_{CP} between samesign inclusive dilepton samples ℓ^{+}ℓ^{+} and ℓ^{}ℓ^{} (ℓ=e, μ) from semileptonic B decays in ϒ(4S)→BB[over ¯] events, using the complete data set recorded by the BABAR experiment near the ϒ(4S) resonance, corresponding to 471×10^{6} BB[over ¯] pairs. The asymmetry A_{CP} allows comparison between the mixing probabilities P(B[over ¯]^{0}→B^{0}) and P(B^{0}→B[over ¯]^{0}), and therefore probes CP and T violation. The result, A_{CP}=[3.9±3.5(stat)±1.9(syst)]×10^{3}, is consistent with the standard model expectation.Physical Review Letters 02/2015; 114(8):081801. · 7.73 Impact Factor 
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ABSTRACT: We present the first upperlimit measurement of the branching fractions of the isospinviolating transitions $\chi_{c0,2} \rightarrow \pi^{0} \eta_{c}$. The measurements are performed using $106\times 10^{6}$ $\psi(3686)$ events accumulated with the BESIII detector at the BEPCII $e^{+}e^{}$ collider at a centerofmass energy corresponding to the $\psi(3686)$ mass. We obtained upper limits on the branching fractions at a 90\% confidence level of $B(\chi_{c0} \rightarrow \pi^{0} \eta_{c}) < 1.6 \times 10^{3}$ and $B(\chi_{c2} \rightarrow \pi^{0} \eta_{c}) < 3.2 \times 10^{3}$. 
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ABSTRACT: We report a measurement of the parameter $y_{CP}$ in $\ensuremath{D^0}\xspace\ensuremath{\overline{D}^{0}}\xspace$ oscillations performed by taking advantage of quantum coherence between pairs of $\ensuremath{D^0}\xspace \ensuremath{\overline{D}^{0}}\xspace$ mesons produced in $e^+e^$ annihilations near threshold. In this work, doublytagged $\ensuremath{D^0}\xspace \ensuremath{\overline{D}^{0}}\xspace$ events, where one $D$ decays to a $CP$ eigenstate and the other $D$ decays in a semileptonic mode, are reconstructed using a data sample of 2.92\,fb$^{1}$ collected with the BESIII detector at the centerofmass energy of $\sqrt{s}$ = 3.773\,GeV. We obtain $y_{CP} = (2.0\pm1.3\pm0.7)\%$, where the first uncertainty is statistical and the second is systematic. This result is compatible with the current world average. 
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ABSTRACT: Based on a sample of $2.25\times 10^{8} J/\psi$ events taken with the BESIII detector at the BEPCII collider, we present the results of a study of the decay $J/\psi\to \eta \phi\pi^{+}\pi^{}$. The $Y(2175)$ resonance is observed in the invariant mass spectrum of $\phi f_{0}(980)$ with a statistical significance of greater than $10\sigma$. The corresponding mass and width are determined to be $M=2200\pm 6 \mathrm{(stat.)} \pm 5\mathrm{(syst.)} \mathrm{MeV}/c^{2}$ and $\Gamma=104\pm 15\mathrm{(stat.)}\pm 15\mathrm{(syst.)}$ MeV, respectively, and the product branching fraction is measured to be $\mathcal{B}(J/\psi\to\eta Y(2175)$, $Y(2175)\to \phi f_{0}(980)$, $f_{0}(980)\to \pi^{+}\pi^{})= (1.20\pm 0.14\mathrm{(stat.)}\pm 0.37 \mathrm{(syst.)})\times 10^{4}$. The results are consistent within errors with those of previous experiments. We also measure the branching fraction of $J/\psi\to \phi f_1(1285)$ with $f_1(1285)\to \eta\pi^{+}\pi^{}$ and set upper limits on the branching fractions for $J/\psi\to \phi\eta(1405)$/$\phi X(1835)$/$\phi X(1870)$ with $\eta(1405)$/$X(1835)$/$X(1870)\to \eta\pi^{+}\pi^{}$ at the 90\% confidence level. 
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ABSTRACT: Using 482 pb$^{1}$ of data taken at $\sqrt{s}=4.009$ GeV, we measure the branching fractions of the decays of $D^{*0}$ into $D^0\pi^0$ and $D^0\gamma$ to be $\BR(D^{*0} \to D^0\pi^0)=(65.5\pm 0.8\pm 0.5)%$ and $\BR(D^{*0} \to D^0\gamma)=(34.5\pm 0.8\pm 0.5)%$ respectively, by assuming that the $D^{*0}$ decays only into these two modes. The ratio of the two branching fractions is $\BR(D^{*0} \to D^0\pi^0)/\BR(D^{*0} \to D^0\gamma) =1.90\pm 0.07\pm 0.05$, which is independent of the assumption made above. The first uncertainties are statistical and the second ones systematic. The precision is improved by a factor of three compared to the present world average values. 
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ABSTRACT: Using data samples collected at centerofmass energies $\sqrt{s} = 4.23$, 4.26, and 4.36~GeV with the BESIII detector operating at the BEPCII storage ring, we search for the production of the charmoniumlike state $Y(4140)$ through a radiative transition followed by its decay to $\phi J/\psi$. No significant signal is observed and upper limits on $\sigma[e^{+} e^{} \rightarrow \gamma Y(4140)] \cdot \mathcal{B}(Y(4140)\rightarrow \phi J/\psi)$ at the $90\%$ confidence level are estimated as 0.35, 0.28, and 0.33~pb at $\sqrt{s} = 4.23$, 4.26, and 4.36~GeV, respectively. 
Article: Evidence for $e^+e^\to\gamma\chi_{c1, 2}$ at centerofmass energies from 4.009 to 4.360 GeV
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ABSTRACT: Using data samples collected at centerofmass energies of $\sqrt{s}$ = 4.009, 4.230, 4.260, and 4.360 GeV with the BESIII detector operating at the BEPCII collider, we perform a search for the process $e^+e^\to\gamma\chi_{cJ}$ $(J = 0, 1, 2)$ and find evidence for $e^+e^\to\gamma\chi_{c1}$ and $e^+e^\to\gamma\chi_{c2}$ with statistical significances of 3.0$\sigma$ and 3.4$\sigma$, respectively. The Born cross sections $\sigma^{B}(e^+e^\to\gamma\chi_{cJ})$, as well as their upper limits at the 90% confidence level are determined at each centerofmass energy. 
Article: Observation of e^{+}e^{}→π^{0}π^{0}h_{c} and a Neutral Charmoniumlike Structure Z_{c}(4020)^{0}
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ABSTRACT: Using data collected with the BESIII detector operating at the Beijing Electron Positron Collider at centerofmass energies of sqrt[s]=4.23, 4.26, and 4.36 GeV, we observe e^{+}e^{}→π^{0}π^{0}h_{c} for the first time. The Born cross sections are measured and found to be about half of those of e^{+}e^{}→π^{+}π^{}h_{c} within less than 2σ. In the π^{0}h_{c} mass spectrum, a structure at 4.02 GeV/c^{2} is found. It is most likely to be the neutral isospin partner of the Z_{c}(4020)^{±} observed in the process of e^{+}e^{}→π^{+}π^{}h_{c} being found. A fit to the π^{0}h_{c} invariant mass spectrum, with the width of the Z_{c}(4020)^{0} fixed to that of its charged isospin partner and possible interferences with nonZ_{c}(4020)^{0} amplitudes neglected, gives a mass of (4023.9±2.2±3.8) MeV/c^{2} for the Z_{c}(4020)^{0}, where the first error is statistical and the second systematic.Physical Review Letters 11/2014; 113(21):212002. · 7.73 Impact Factor 
Article: The Physics of the B Factories
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ABSTRACT: This work is on the Physics of the B Factories. Part A of this book contains a brief description of the SLAC and KEK B Factories as well as their detectors, BaBar and Belle, and data taking related issues. Part B discusses tools and methods used by the experiments in order to obtain results. The results themselves can be found in Part C.European Physical Journal C 11/2014; DOI:10.1140/epjc/s1005201430269 · 5.44 Impact Factor 
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ABSTRACT: Dark sectors charged under a new Abelian interaction have recently received much attention in the context of dark matter models. These models introduce a light new mediator, the socalled dark photon (A^{'}), connecting the dark sector to the standard model. We present a search for a dark photon in the reaction e^{+}e^{}→γA^{'}, A^{'}→e^{+}e^{}, μ^{+}μ^{} using 514 fb^{1} of data collected with the BABAR detector. We observe no statistically significant deviations from the standard model predictions, and we set 90% confidence level upper limits on the mixing strength between the photon and dark photon at the level of 10^{4}10^{3} for dark photon masses in the range 0.0210.2 GeV. We further constrain the range of the parameter space favored by interpretations of the discrepancy between the calculated and measured anomalous magnetic moment of the muon.Physical Review Letters 11/2014; 113(20):201801. · 7.73 Impact Factor 
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ABSTRACT: Using a sample of $2.25\times 10^8$ $J/\psi$ events collected with the BESIII detector at the BEPCII collider, we search for the $J/\psi$ semileptonic weak decay $J/\psi \to D^{}_{s} e^{+}\nu_{e}+c.c.$ with a much higher sensitivity than previous searches. We also perform the first search for $J/\psi \to D^{*}_{s} e^{+}\nu_{e}+c.c.$ No significant excess of a signal above background is observed in either channel. At the $90\%$ confidence level, the upper limits are determined to be $\mathcal{B}(J/\psi \to D^{}_{s}e^{+}\nu_{e}+c.c.)<1.3\times10^{6}$ and $\mathcal{B}(J/\psi \to {D^{*}_{s}}^{}e^{+}\nu_{e}+c.c.)<1.8\times10^{6}$, respectively. Both are consistent with Standard Model predictions. 
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ABSTRACT: Based on data samples collected with the BESIII detector at the BEPCII collider at 9 centerofmass energies from 4.21 to 4.42 GeV, we search for the production of $e^+e^\to \omega\chi_{cJ}$ ($J$=0, 1, 2). The process $e^+e^\to \omega\chi_{c0}$ is observed for the first time, and the Born cross sections at $\sqrt{s}$=4.23 and 4.26 GeV are measured to be $(55.4\pm 6.0\pm 5.9)$ and $(23.7\pm 5.3\pm 3.5)$ pb, respectively, where the first uncertainties are statistical and the second are systematic. The $\omega\chi_{c0}$ signals at the other 7 energies and $e^+e^\to \omega\chi_{c1}$ and $\omega\chi_{c2}$ signals are not significant, and the upper limits on the cross sections are determined. By examining the $\omega\chi_{c0}$ cross section as a function of centerofmass energy, we find that it is inconsistent with the line shape of the $Y(4260)$ observed in $e^+ e^\to\pi^+\pi^J/\psi$. 
Article: Observation of $e^+e^\to \pi^0\pi^0 h_c$ and a neutral charmoniumlike structure $Z_c(4020)^0$
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ABSTRACT: Using data collected with the BESIII detector operating at the Beijing Electron Positron Collider at centerofmass energies of $\sqrt{s}$=4.23, 4.26, and 4.36 GeV, we observe $e^+e^\to \pi^0\pi^0 h_c$ for the first time. The Born cross sections are measured and found to be about half of those of $e^+e^ \to \pi^+\pi^h_c$ within less than 2$\sigma$. In the $\pi^0h_c$ mass spectrum, a structure at 4.02~GeV/$c^2$ that is most likely the neutral isospin partner of the $Z_c(4020)^{\pm}$ observed in the process of $e^+e^ \to \pi^+\pi^h_c$ is found. A fit to the $\pi^0 h_c$ invariant mass spectrum with the width of the $Z_c(4020)^0$ fixed to that of its charged isospin partner and possible interferences with non$Z_c(4020)^0$ amplitudes neglected, gives a mass of ($4023.9\pm 2.2 \pm 3.8$)~MeV/$c^2$ for the $Z_c(4020)^0$, where the first error is statistical and the second systematic. 
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ABSTRACT: Using $1.06\times10^8$ $\psi(3686)$ events recorded in $e^{+}e^{}$ collisions at $\sqrt{s}=$ 3.686 GeV with the BESIII at the BEPCII collider, we present searches for Cparity violation in $J/\psi \to \gamma\gamma$ and $ \gamma \phi$ decays via $\psi(3686) \to J/\psi \pi^+\pi^$. No significant signals are observed in either channel. Upper limits on the branching fractions are set to be $\mathcal{B}(J/\psi \to \gamma\gamma) < 2.7 \times 10^{7}$ and $\mathcal{B}(J/\psi \to \gamma\phi) < 1.4 \times 10^{6}$ at the 90\% confidence level. The former is one order of magnitude more stringent than the previous upper limit, and the latter represents the first limit on this decay channel. 
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ABSTRACT: Using $2.25\times10^{8}$ $J/\psi$ events collected with the BESIII detector at the BEPCII storage rings, we observe for the first time the process $J/\psi\rightarrow p\bar{p}a_{0}(980)$, $a_{0}(980)\rightarrow \pi^{0}\eta$ with a significance of $6.5\sigma$ ($3.2\sigma$ including systematic uncertainties). The product branching fraction of $J/\psi\rightarrow p\bar{p}a_{0}(980)\rightarrow p\bar{p}\pi^{0}\eta$ is measured to be $(6.8\pm1.2\pm1.5)\times 10^{5}$, where the first error is statistical and the second is systematic. This measurement provides information on the $a_{0}$ production near threshold coupling to $p\bar{p}$ and improves the understanding of the dynamics of $J/\psi$ decays to four body processes.
Publication Stats
5k  Citations  
3,234.66  Total Impact Points  
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Institutions

2014–2015

University of Ferrara
Ferrare, EmiliaRomagna, Italy


1984–2012

INFN  Istituto Nazionale di Fisica Nucleare
Frascati, Latium, Italy


2006–2010

Université de Savoie
Chambéry, RhôneAlpes, France 
Università degli Studi di Torino
Torino, Piedmont, Italy


2007

RuhrUniversität Bochum
 Institut für Experimentalphysik I
Bochum, North RhineWestphalia, Germany


2003

Scuola Normale Superiore di Pisa
Pisa, Tuscany, Italy


1997

University of Rome Tor Vergata
 Dipartimento di Fisica
Roma, Latium, Italy
