Publications (329)999.17 Total impact
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ABSTRACT: In an analysis of a 2.92~fb$^{1}$ data sample taken at 3.773~GeV with the BESIII detector operated at the BEPCII collider, we measure the absolute decay branching fractions to be $\mathcal B(D^0 \to K^e^+\nu_e)=(3.505\pm 0.014 \pm 0.033)\%$ and $\mathcal B(D^0 \to \pi^e^+\nu_e)=(0.295\pm 0.004\pm 0.003)\%$. From a study of the differential decay rates we obtain the products of hadronic form factor and the magnitude of the CKM matrix element $f_{+}^K(0)V_{cs}=0.7172\pm0.0025\pm 0.0035$ and $f_{+}^{\pi}(0)V_{cd}=0.1435\pm0.0018\pm 0.0009$. Combining these products with the values of $V_{cs(d)}$ from the SM constraint fit, we extract the hadronic form factors $f^K_+(0) = 0.7368\pm0.0026\pm 0.0036$ and $f^\pi_+(0) = 0.6372\pm0.0080\pm 0.0044$, and their ratio $f_+^{\pi}(0)/f_+^{K}(0)=0.8649\pm 0.0112\pm 0.0073$. These form factors and their ratio are used to test unquenched Lattice QCD calculations of the form factors and a light cone sum rule (LCSR) calculation of their ratio. The measured value of $f_+^{K(\pi)}(0) V_{cs(d)}$ and the lattice QCD value for $f^{K(\pi)}_+(0)$ are used to extract values of the CKM matrix elements of $V_{cs}=0.9601 \pm 0.0033 \pm 0.0047 \pm 0.0239$ and $V_{cd}=0.2155 \pm 0.0027 \pm 0.0014 \pm 0.0094$, where the third errors are due to the uncertainties in lattice QCD calculations of the form factors. Using the LCSR value for $f_+^\pi(0)/f_+^K(0)$, we determine the ratio $V_{cd}/V_{cs}=0.238\pm 0.004\pm 0.002\pm 0.011$, where the third error is from the uncertainty in the LCSR normalization. In addition, we measure form factor parameters for three different theoretical models that describe the weak hadronic charged currents for these two semileptonic decays. All of these measurements are the most precise to date.  [Show abstract] [Hide abstract]
ABSTRACT: Charge dipole moment and spin moment rarely coexist in singlephase bulk materials except in some multiferroics. Despite the progress in the past decade, for most multiferroics their magnetoelectric performance remains poor due to the intrinsic exclusion between charge dipole and spin moment. As an alternative approach, the oxide heterostructures may evade the intrinsic limits in bulk materials and provide more attractive potential to realize the magnetoelectric functions. Here we perform a firstprinciples study on LaAlO$_3$/PbTiO$_3$ superlattices. Although neither of the components is magnetic, magnetic moments emerge at the ferroelectric domain walls of PbTiO$_3$ in these superlattices. Such a twist between ferroelectric domain and local magnetic moment, not only manifests an interesting type of multiferroicity, but also is possible useful to pursuit the electricalcontrol of magnetism in nanoscale heterostructures.Scientific Reports 08/2015; 5. DOI:10.1038/srep13052 · 5.58 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: Using 2.92 fb$^{1}$ of electronpositron annihilation data collected at a centerofmass energy of $\sqrt{s}= 3.773$ GeV with the BESIII detector, we present an improved measurement of the branching fraction $\mathcal{B}(D^+ \to \omega e^+ \nu_{e}) = (1.63\pm0.11\pm0.08)\times 10^{3}$. The parameters defining the corresponding hadronic form factor ratios at zero momentum transfer are determined for the first time, we measure them to be $r_V = 1.24\pm0.09\pm0.06$ and $r_2 = 1.06\pm0.15 \pm 0.05$. The first and second uncertainties are statistical and systematic, respectively. We also search for the decay $D^+ \to \phi e^+ \nu_{e}$. An improved upper limit $\mathcal{B}(D^+ \to \phi e^+ \nu_{e}) < 1.3 \times 10^{5}$ is set at 90\% confidence level.  [Show abstract] [Hide abstract]
ABSTRACT: We extract the $e^+e^\rightarrow \pi^+\pi^$ cross section in the energy range between 600 and 900 MeV, exploiting the method of initial state radiation. A data set with an integrated luminosity of 2.93 fb$^{1}$ taken at a centerofmass energy of 3.773 GeV with the BESIII detector at the BEPCII collider is used. The cross section is measured with a systematic uncertainty of 0.9%. We extract the pion form factor $F_\pi^2$ as well as the contribution of the measured cross section to the leading order hadronic vacuum polarization contribution to $(g2)_\mu$. We find this value to be $a_\mu^{\pi\pi,\rm LO}(600900\;\rm MeV) = (372.5 \pm 2.6_{\rm stat} \pm 3.4_{\rm sys})\cdot 10^{10}$.  [Show abstract] [Hide abstract]
ABSTRACT: We present a measurement of the azimuthal asymmetries of two charged pions in the inclusive process $e^+e^\rightarrow \pi\pi X$. These asymmetries can be attributed to the Collins fragmentation function, which describes the behavior of a hadron produced from a transversely polarized quark. This work is performed using a data set of 62 $\rm{pb}^{1}$ at the centerofmass energy $\sqrt{s}=3.65$ GeV collected with the BESIII detector at the BEPCII storage rings, where the corresponding fourmomentum transfer of the virtual photon, $Q^2$, is close to the energy scale of the existing semiinclusive DIS experimental data. We observe a nonzero asymmetry, which increases with increasing pion momentum and also indicates a larger spindependent Collins effect than at higher energy scale. The dependence of the asymmetry on the transverse momentum of hadrons to the reference axis is also investigated. The measured asymmetries are important inputs for the global analysis of extracting the quark transversity distribution inside the nucleon, and are valuable to explore the energy evolution of the spindependent fragmentation function.  [Show abstract] [Hide abstract]
ABSTRACT: Based on a sample of \etapr mesons produced in the radiative decay $J/\psi\to\gamma\eta^{\prime}$ in $1.31\times 10^9$ $J/\psi$ events collected with the BESIII detector, the decay $\eta^{\prime}\to\omega e^{+} e^{}$ is observed for the first time, with a statistical significance of $8\sigma$. The branching fraction is measured to be $\mathcal{B}(\eta^{\prime}\to\omega e^{+} e^{})=(1.97\pm0.34(\text{stat})\pm0.17(\text{syst}))\times10^{4}$, which is in agreement with theoretical predictions. The branching fraction of $\eta^{\prime}\to\omega\gamma$ is also measured to be $(2.55\pm0.03(\text{stat})\pm0.16(\text{syst}))\times10^{2}$, which is the most precise measurement to date, and the relative branching fraction $\frac{\mathcal{B}(\eta^{\prime}\to \omega e^{+}e^{})}{\mathcal{B}(\eta^{\prime}\to \omega \gamma)}$ is determined to be $(7.71\pm1.34(\text{stat})\pm0.54(\text{syst}))\times10^{3}$.  [Show abstract] [Hide abstract]
ABSTRACT: We report a study of the process $e^{+} e^{} \to (D^{*} \bar{D}^{*})^{0} \pi^0$ using $e^+e^$ collision data samples with integrated luminosity of $1092 \rm{pb}^{1}$ at $\sqrt{s}=4.23 \rm{GeV}$ and $826 \rm{pb}^{1}$ at $\sqrt{s}=4.26 \rm{GeV}$ collected with the BESIII detector at the BEPCII storage ring. We observe a new neutral structure near the $(D^{*} \bar{D}^{*})^{0}$ mass threshold in the $\pi^0$ recoil mass spectrum, which we denote as $Z_{c}(4025)^{0}$. Assuming a BreitWigner line shape, its pole mass and pole width are determined to be $(4025.5^{+2.0}_{4.7}\pm3.1) \rm{MeV}/c^2$ and $(23.0\pm 6.0\pm 1.0) \rm{MeV}$, respectively. The statistical significance of the observation is $7.4\sigma$. The Born cross sections of $e^{+}e^{}\to Z_{c}(4025)^{0} \pi^0\to (D^{*} \bar{D}^{*})^{0}\pi^0$ are measured to be $(61.6\pm8.2\pm9.0) \rm{pb}$ at $\sqrt{s}=4.23 \rm{GeV}$ and $(43.4\pm8.0\pm5.4) \rm{pb}$ at $\sqrt{s}=4.26 \rm{GeV}$. The first uncertainties are statistical and the second are systematic.  [Show abstract] [Hide abstract]
ABSTRACT: The decay $Z_c(3900)^\pm\to\omega\pi^\pm$ is searched for using data samples collected with the BESIII detector operating at the BEPCII storage ring at centerofmass energies $\sqrt{s}=4.23$ and $4.26$~GeV. No significant signal for the $Z_c(3900)^\pm$ is found, and upper limits at the 90\% confidence level on the Born cross section for the process $e^+e^\to Z_c(3900)^\pm\pi^\mp\to\omega\pi^+\pi^$ are determined to be $0.26$ and $0.18$ pb at $\sqrt{s}=4.23$ and 4.26 GeV, respectively.  [Show abstract] [Hide abstract]
ABSTRACT: We study $D_{s}^{+}$ decays to final states involving the $\eta'$ with a 482\,pb$^{1}$ data sample collected at $\sqrt{s}$ = 4.009\,GeV with the \mbox{BESIII} detector at the BEPCII collider. We measure the branching fractions $\mathcal{B}(D^+_{s}\rightarrow \eta'X)$ = (8.8$\pm$1.8$\pm$0.5)\% and $\mathcal{B}(D_{s}^{+}\rightarrow \eta'\rho^{+})$ = ($5.8\pm1.4\pm0.4$)\% where the first uncertainty is statistical and the second is systematic. In addition, we estimate an upper limit on the nonresonant branching ratio $\mathcal{B}(D_{s}^{+}\rightarrow \eta'\pi^+\pi^0)<5.1\%$ at the 90\% confidence level. Our results are consistent with CLEO's recent measurements and help to resolve the disagreement between the theoretical prediction and CLEO's previous measurement of $\mathcal{B}(D_{s}^{+}\rightarrow \eta'\rho^{+})$.  [Show abstract] [Hide abstract]
ABSTRACT: The Casimir effect is a general phenomenon in physics, which arises when the vacuum fluctuation of an arbitrary field is modified by static or slowly varying boundary. However, its spin version is rarely addressed, mainly due to the fact that a macroscopic boundary in quantum spin systems is hard to define. In this article, we explore the spin Casimir effect induced by the zeropoint fluctuation of spin waves in a general noncollinear ordered quantum antiferromagnet. This spin Casimir effect results in a spin torque between local spins and further causes various singular and divergent results in the framework of spinwave theory, which invalidate the standard $1/S$ expansion procedure. To avoid this dilemma, we develop a selfconsistent spinwave expansion approach, which preserves the spinwave expansion away from singularities and divergence. A detailed spinwave analysis of the antiferromagnetic spin1/2 Heisenberg model on a spatially anisotropic triangular lattice is undertaken within our approach. Our results indicate that the spiral order is only stable in the region $0.5<\alpha<1.2$, where $\alpha$ is the ratio of the coupling constants. In addition, the instability in the region $1.2<\alpha<2$ is owing to the spin Casimir effect instead of the vanishing sublattice magnetization. And this extended spiral instable region may host some quantum disordered phases besides the quantum order by disorder induced Neel phase. Furthermore, our method provides an efficient and convenient tool that can estimate the correct exchange parameters and outline the quantum phase diagrams, which can be useful for experimental fitting processes in frustrated quantum magnets.  [Show abstract] [Hide abstract]
ABSTRACT: Based on a sample of $1.31 \times 10^9$ $J/\psi$ events collected with the BESIII detector at the BEPCII collider, Dalitz plot analyses of selected 79,625 $\eta\rightarrow\pi^{+}\pi^{}\pi^0$ events, 33,908 $\eta\rightarrow\pi^0\pi^0\pi^0$ events and 1,888 $\eta^{\prime}\rightarrow\pi^0\pi^0\pi^0$ events are performed. The measured matrix elements of $\eta\rightarrow\pi^+\pi^\pi^0$ are in reasonable agreement with previous measurements. The Dalitz plot slope parameters of $\eta\rightarrow\pi^0\pi^0\pi^0$ and $\eta^{\prime}\rightarrow\pi^0\pi^0\pi^0$ are determined to be $0.055 \pm 0.014 \pm 0.004$ and $0.640 \pm 0.046 \pm 0.047$, respectively, where the first uncertainties are statistical and the second systematic. Both values are consistent with previous measurements, while the precision of the latter one is improved by a factor of three. Final state interactions are found to have an important role in those decays.  [Show abstract] [Hide abstract]
ABSTRACT: We report an observation of the process $J/\psi\rightarrow\gamma X(1835)\rightarrow\gamma K^0_S K^0_S\eta$ at low $K^0_S K^0_S$ mass with a statistical significance larger than 12.9$\sigma$ using a data sample of $1.31 \times 10^{9}$ $J/\psi$ events collected with the BESIII detector. In this region of phase space the $K^0_S K^0_S$ system is dominantly produced through the $f_0(980)$. By performing a partial wave analysis, we determine the spinparity of the $X(1835)$ to be $J^{PC}=0^{+}$. The mass and width of the observed $X(1835)$ are $1844\pm9(\text{stat})^{+16}_{25}(\text{syst})$~\MeV~and $192^{+20}_{17}(\text{stat})^{+62}_{43}(\text{syst})$~MeV, respectively, which are consistent with the results obtained by BESIII in the channel $J/\psi\rightarrow\gamma\pi^+\pi^\eta^{\prime}$.  [Show abstract] [Hide abstract]
ABSTRACT: An amplitude analysis of the $\pi^{0}\pi^{0}$ system produced in radiative $J/\psi$ decays is presented. In particular, a piecewise function that describes the dynamics of the $\pi^{0}\pi^{0}$ system is determined as a function of $M_{\pi^{0}\pi^{0}}$ from an analysis of the $(1.311\pm0.011)\times10^{9}$ $J/\psi$ decays collected by the BESIII detector. The goal of this analysis is to provide a description of the scalar and tensor components of the $\pi^0\pi^0$ system while making minimal assumptions about the properties or number of poles in the amplitude. Such a modelindependent description allows one to integrate these results with other related results from complementary reactions in the development of phenomenological models, which can then be used to directly fit experimental data to obtain parameters of interest. The branching fraction of $J/\psi \to \gamma \pi^{0}\pi^{0}$ is determined to be $(1.15\pm0.05)\times10^{3}$, where the uncertainty is systematic only and the statistical uncertainty is negligible.  [Show abstract] [Hide abstract]
ABSTRACT: Using a sample of 1.31 billion $J/\psi$ events collected with the BESIII detector at the BEPCII collider, the decays $J/\psi \to \phi \pi^{+}\pi^{}\pi^{0}$ and $J/\psi \to \phi \pi^{0}\pi^{0}\pi^{0}$ are investigated. The isospin violating decay $J/\psi \to \phi \pi^{0} f_{0}(980)$ with $f_{0}(980) \to \pi\pi$, is observed for the first time. The width of the $f_{0}(980)$ obtained from the dipion mass spectrum is found to be much smaller than the world average value. In the $\pi^{0} f_{0}(980)$ mass spectrum, there is evidence of $f_1(1285)$ production. By studying the decay $J/\psi \to \phi\eta'$, the branching fractions of $\eta' \to \pi^{+}\pi^{}\pi^{0}$ and $\eta' \to \pi^{0}\pi^{0}\pi^{0}$, as well as their ratio, are also measured.  [Show abstract] [Hide abstract]
ABSTRACT: Using $2.92$ fb$^{1}$ of electronpositron annihilation data collected at $\sqrt{s} = 3.773$~GeV with the BESIII detector, we report the results of a search for the flavorchanging neutral current process $D^0\to\gamma\gamma$ using a doubletag technique. We find no signal and set an upper limit at $90\%$ confidence level for the branching fraction of $B(D^0\to\gamma\gamma) < 3.8\times10^{6}$. We also investigate $D^0$meson decay into two neutral pions, obtaining a branching fraction of $B(D^0\to\pi^0\pi^0) = (8.24\pm0.21(\text{stat.})\pm0.30(\text{syst.}))\times10^{4}$, the most precise measurement to date and consistent with the current world averagePhysical Review D 05/2015; 91(11). DOI:10.1103/PhysRevD.91.112015 · 4.64 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: Using the data sets taken at centerofmass energies above 4 GeV by the BESIII detector at the BEPCII storage ring, we search for the reaction e+e > gamma_ISR X(3872) > gamma_ISR pi+piJ/psi via the Initial State Radiation technique. The production of a resonance with quantum numbers J^PC = 1^++ such as the X(3872) via single photon e+e annihilation is forbidden, but is allowed by a nexttoleading order box diagram. We do not observe a significant signal of X(3872), and therefore give an upper limit for the electronic width times the branching fraction Gamma_ee^X(3872)Br(X(3872) > pi+piJ\psi) < 0.13 eV at the 90% confidence level. This measurement improves upon existing limits by a factor of 46. Using the same final state, we also measure the electronic width of the psi(3686) to be Gamma_ee^psi(3686) = 2231 + 18 + 99 eV.  [Show abstract] [Hide abstract]
ABSTRACT: Using data samples collected at center of mass energies of $\sqrt{s}$ = 4.009, 4.226, 4.257, 4.358, 4.416 and 4.599 GeV with the BESIII detector operating at the BEPCII storage ring, we search for the isospin violating decay $Y(4260)\rightarrow J/\psi \eta \pi^{0}$. No signal is observed, and upper limits on the cross section $\sigma(e^{+}e^{}\rightarrow J/\psi \eta \pi^{0})$ at the 90\% confidence level are determined to be 3.6, 1.7, 2.4, 1.4, 0.9 and 1.9 pb, respectively.  [Show abstract] [Hide abstract]
ABSTRACT: We report a measurement of the branching fraction of $\psi(3770)\to\gamma\chi_{c1}$ and search for the transition $\psi(3770)\rightarrow \gamma \chi_{c2}$ based on 2.92~fb$^{1}$ of $e^+e^$ data accumulated at $\sqrt{s}=3.773$~GeV with the BESIII detector at the BEPCII collider. The measured branching fraction of $\psi(3770) \rightarrow \gamma \chi_{c1}$ is $\mathcal B(\psi(3770) \rightarrow \gamma \chi_{c1})=(2.48 \pm 0.15 \pm 0.23) \times 10^{3}$, which is the most precise measurement to date. The upper limit on the branching fraction of $\psi(3770)\rightarrow \gamma \chi_{c2}$ at a $90\%$ confidence level is $\mathcal B(\psi(3770) \rightarrow \gamma \chi_{c2})<0.64 \times 10^{3}$. The corresponding partial widths are $\Gamma(\psi(3770) \to \gamma \chi_{c1}) =(67.5\pm 4.1\pm 6.7)$~keV and $\Gamma(\psi(3770) \to \gamma \chi_{c2}) < 17.4$~keV.  [Show abstract] [Hide abstract]
ABSTRACT: We report the first observation of the Dalitz decay $\eta' \to \gamma e^+e^$, based on a data sample of 1.31 billion $J/\psi$ events collected with the BESIII detector. The $\eta'$ mesons are produced via the $J/\psi \to \gamma \eta'$ decay process. The ratio $\Gamma(\eta' \to \gamma e^+ e^)/\Gamma(\eta'\to\gamma\gamma)$ is measured to be $(2.13\pm0.09(\text{stat.})\pm0.07(\text{sys.}))\times10^{2}$. This corresponds to a branching fraction ${\cal B}(\eta' \to \gamma e^+e^)= (4.69 \pm0.20(\text{stat.})\pm0.23(\text{sys.}))\times10^{4}$. The transition form factor is extracted and different expressions are compared to the measured dependence on the $e^+e^$ invariant mass. The results are consistent with the prediction of the Vector Meson Dominance model.  [Show abstract] [Hide abstract]
ABSTRACT: Using data samples collected with the BESIII detector at the BEPCII collider, we measure the Born cross section of $e^{+}e^{}\rightarrow p\bar{p}$ at 12 centerofmass energies from 2232.4 to 3671.0 MeV. The corresponding effective electromagnetic form factor of the proton is deduced under the assumption that the electric and magnetic form factors are equal $(G_{E}= G_{M})$. In addition, the ratio of electric to magnetic form factors, $G_{E}/G_{M}$, and $G_{M}$ are extracted by fitting the polar angle distribution of the proton for the data samples with larger statistics, namely at $\sqrt{s}=$ 2232.4 and 2400.0 MeV and a combined sample at $\sqrt{s}$ = 3050.0, 3060.0 and 3080.0 MeV, respectively. The measured cross sections are in agreement with recent results from BaBar, improving the overall uncertainty by about 30\%. The $G_{E}/G_{M}$ ratios are close to unity and consistent with BaBar results in the same $q^{2}$ region, which indicates the data are consistent with the assumption that $G_{E}=G_{M}$ within uncertainties.
Publication Stats
2k  Citations  
999.17  Total Impact Points  
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Institutions

2009–2015

Nanjing University
 Department of Physics
Nanching, Jiangsu Sheng, China 
Guangxi University
Yungning, Guangxi Zhuangzu Zizhiqu, China


1998–2014

Institute of physics china
Peping, Beijing, China 
Hangzhou University
Shanghai, Shanghai Shi, China


2013

Chinese Academy of Sciences
Peping, Beijing, China


2004–2013

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


2011

Henan University of Science and Technology
Honanfu, Henan Sheng, China


2010

RuhrUniversitÃ¤t Bochum
Bochum, North RhineWestphalia, Germany


1984–2010

Nankai University
Tâ€™ienchingshih, Tianjin Shi, China


2008

University of Toronto
Toronto, Ontario, Canada


2007–2008

University of Jinan (Jinan, China)
Chinanshih, Shandong Sheng, China


2006

Uppsala University
Uppsala, Uppsala, Sweden


2000–2001

Shanghai Jiao Tong University
Shanghai, Shanghai Shi, China


1999

National Tsing Hua University
 Nuclear Science and Technology Development Center
Hsinchuhsien, Taiwan, Taiwan 
Peking University
 Department of Technical Physics
Peping, Beijing, China


1992

Boston University
Boston, Massachusetts, United States
