No Arabic abstract
We report the measurement of $e^+e^- to D^+_sD^*_{s2}(2573)^-+c.c.$ via initial-state radiation using a data sample of an integrated luminosity of 921.9 fb$^{-1}$ collected with the Belle detector at the $Upsilon(4S)$ and nearby. We find evidence for an enhancement with a 3.4$sigma$ significance in the invariant mass of $D^+_sD^*_{s2}(2573)^- +c.c.$ The measured mass and width are $(4619.8^{+8.9}_{-8.0}({rm stat.})pm2.3({rm syst.}))~{rm MeV}/c^{2}$ and $(47.0^{+31.3}_{-14.8}({rm stat.})pm4.6({rm syst.}))~{rm MeV}$, respectively. The mass, width, and quantum numbers of this enhancement are consistent with the charmonium-like state at 4626 MeV/$c^2$ recently reported by Belle in $e^+e^-to D^+_sD_{s1}(2536)^-+c.c.$ The product of the $e^+e^-to D^+_sD^*_{s2}(2573)^-+c.c.$ cross section and the branching fraction of $D^*_{s2}(2573)^-to{bar D}^0K^-$ is measured from $D^+_sD^*_{s2}(2573)^-$ threshold to 5.6 GeV.
Using a data sample of 921.9 fb$^{-1}$ collected with the Belle detector, we study the process of $e^+e^-to D^+_sD_{s1}(2536)^-+c.c.$ via initial-state radiation. We report the first observation of a vector charmoniumlike state decaying to $D^+_sD_{s1}(2536)^-+c.c.$ with a significance of 5.9$sigma$, including the systematic uncertainties. The measured mass and width are $(4625.9^{+6.2}_{-6.0}({rm stat.})pm0.4({rm syst.}))~{rm MeV}/c^{2}$ and $(49.8^{+13.9}_{-11.5}({rm stat.})pm4.0({rm syst.}))~{rm MeV}$, respectively. The product of the $e^+e^-to D^+_sD_{s1}(2536)^-+c.c.$ cross section and the branching fraction of $D_{s1}(2536)^-to{bar D}^{*0}K^-$ is measured from the $D_s bar{D}_{s1}(2536)$ threshold to 5.59~GeV.
Using the data samples of $(1310.6pm7.2 )times 10^{6}$ $J/psi$ events and $(448.1pm2.9)times 10^{6}$ $psi(3686)$ events collected with the BESIII detector, we search for the rare decays $J/psi to D^{0} e^{+}e^{-} +c.c.$ and $psi(3686) to D^{0} e^{+}e^{-} +c.c.$. No significant signals are observed and the corresponding upper limits on the branching fractions at the $90%$ confidence level are determined to be $Br(J/psi to D^{0} e^{+}e^{-} +c.c.)< 8.5times 10^{-8}$ and $Br (psi(3686) to D^{0} e^{+}e^{-} +c.c.)<1.4times 10^{-7}$, respectively. Our limit on $Br(J/psi to D^{0} e^{+}e^{-} +c.c.)$ is more stringent by two orders of magnitude than the previous results, and the $Br(psi(3686) to D^{0} e^{+}e^{-} +c.c.)$ is measured for the first time.
The cross section for $e^+ e^- to pi^+ pi^- J/psi$ between 3.8 GeV and 5.5 GeV is measured with a 967 fb$^{-1}$ data sample collected by the Belle detector at or near the $Upsilon(nS)$ ($n = 1, 2, ..., 5$) resonances. The Y(4260) state is observed, and its resonance parameters are determined. In addition, an excess of $pi^+ pi^- J/psi$ production around 4 GeV is observed. This feature can be described by a Breit-Wigner parameterization with properties that are consistent with the Y(4008) state that was previously reported by Belle. In a study of $Y(4260) to pi^+ pi^- J/psi$ decays, a structure is observed in the $M(pi^pmjpsi)$ mass spectrum with $5.2sigma$ significance, with mass $M=(3894.5pm 6.6pm 4.5) {rm MeV}/c^2$ and width $Gamma=(63pm 24pm 26)$ MeV/$c^{2}$, where the errors are statistical and systematic, respectively. This structure can be interpreted as a new charged charmonium-like state.
The processes $e^+e^-to D_s^+ D_{s1}(2460)^- +c.c.$ and $e^+e^-to D_s^{ast +} D_{s1}(2460)^- +c.c.$ are studied for the first time using data samples collected with the BESIII detector at the BEPCII collider. The Born cross sections of $e^+e^-to D_s^+ D_{s1}(2460)^- +c.c.$ at nine center-of-mass energies between 4.467,GeV and 4.600,GeV and those of $e^+e^-to D_s^{ast +} D_{s1}(2460)^- +c.c.$ at ${sqrt s}=$ 4.590,GeV and 4.600,GeV are measured. No obvious charmonium or charmonium-like structure is seen in the measured cross sections.
Using $10.1times10^{9}$ $J/psi$ events produced by the Beijing Electron Positron Collider (BEPCII) at a center-of-mass energy $sqrt{s}=3.097~rm{GeV}$ and collected with the BESIII detector, we present a search for the rare semi-leptonic decay $J/psito D^{-}e^{+} u_{e}+c.c.$. No excess of signal above background is observed, and an upper limit on the branching fraction $mathcal{B}(J/psito D^{-}e^{+} u_{e}+c.c.)<7.1times10^{-8}$ is obtained at $90%$ confidence level. This is an improvement of more than two orders of magnitude over the previous best limit.