Using a data sample of \(4.481\times 10^8 \psi^\prime\) events collected with the BESIII detector, we report the first observation of the four-lepton-decays \(J/\psi\to e^+e^-e^+e^-\) and \(J/\psi\to ...e^+e^-\mu^+\mu^-\) utilizing the process \(\psi^\prime\to \pi^+\pi^- J/\psi\). The branching fractions are determined to be \(5.48\pm0.31~(\rm stat)\pm0.45~(\rm syst)\times 10^{-5}\) and \(3.53~\pm0.22~(\rm stat)\pm0.13~(\rm syst)\times 10^{-5}\), respectively. The results are consistent with theoretical predictions. No significant signal is observed for \(J/\psi\to \mu^+\mu^-\mu^+\mu^-\), and an upper limit on the branching fraction is set at \(1.6\times 10^{-6}\) at the 90\(\%\) confidence level. A CP asymmetry observable is constructed for the first two channels, which is measured to be \((-0.012\pm0.054\pm0.010)\) and \((0.062\pm0.059\pm0.006)\), respectively. No evidence for CP violation is observed in this process.
By analyzing \((448.1\pm2.9)\times10^6\) \(\psi(3686)\) events collected with the BESIII detector operating at the BEPCII collider, the decays of \(\chi_{cJ} \to \Lambda\bar \Lambda \eta\) (\(J=0\), ...1 and 2) are observed for the first time with statistical significances of \(13.9\sigma\), \(6.7\sigma\), and \(8.2\sigma\), respectively. The product branching fractions of \(\psi(3686)\to\gamma\chi_{cJ}\) and \(\chi_{cJ}\to \Lambda\bar \Lambda \eta\) are measured. Dividing by the world averages of the branching fractions of \(\psi(3686)\to\gamma\chi_{cJ}\), the branching fractions of \(\chi_{cJ}\to \Lambda\bar \Lambda \eta\) decays are determined to be \((2.31\pm0.30\pm0.21)\times10^{-4}\), \((5.86\pm1.38\pm0.68)\times10^{-5}\), and \((1.05\pm0.21\pm0.15)\times10^{-4}\) for \(J=0\), 1 and 2, respectively, where the first uncertainties are statistical and the second systematic.
The cross section of the process \(e^{+}e^{-}\to\omega\pi^{0}\pi^{0}\) is measured at nineteen center-of-mass energies from 2.0 to 3.08 GeV using data collected with the BESIII detector at the BEPCII ...storage ring. A resonant structure around 2.20 GeV is observed with statistical significance larger than \(5\sigma\). Using a coherent fit to the cross section line shape, the mass and width are determined to be \(M=2222\pm7\pm2~{\rm MeV}/c^2\) and \(\varGamma=59\pm30\pm6~{\rm MeV}\), respectively, where the first uncertainties are statistical and the second ones are systematic.
We present a study of the resonant structure of the decay \(D^0 \to K_{\rm L}^0\pi^+\pi^-\), using quantum-correlated \(D^0\bar{D}^0\) data produced at \(\sqrt{s}=3.773\) GeV. The data sample was ...collected by the BESIII experiment and corresponds to an integrated luminosity of \(2.93\) fb\(^{-1}\). This study is the first amplitude analysis of a decay mode involving a \(K_{\rm L}^0\), which also results in the first measurement of the complex \(\textit{U-spin breaking parameters}\) (\(\hat{\rho}\)) related to various \(\mathit{CP}\)-eigenstate resonant modes through which the three-body decay proceeds. The moduli of the \(\hat{\rho}\) parameters have central values in a wide range from \(0.4\) to \(12.1\), which indicates substantial U-spin symmetry breaking. We present the fractional resonant contributions and average strong-phase parameters over regions of phase space for both \(K_{\rm S}^0\pi^+\pi^-\) and \(K_{\rm L}^0\pi^+\pi^-\) modes. We also report the ratio of the branching fractions between \(K_{\rm L}^0\pi^+\pi^-\) and \(K_{\rm S}^0\pi^+\pi^-\) decay modes and the \(\mathit{CP}\)-even fraction of the \(K_{\rm L}^0\pi^+\pi^-\) state calculated using the U-spin breaking parameters.
Using a data sample of \((448.1 \pm 2.9)\times10^6 ~\psi(3686)\) decays collected at an \(e^+ e^-\) center-of-mass energy of \(3.686~\rm{GeV}\) by the BESIII detector at BEPCII, we report an ...observation of the hindered electromagnetic Dalitz decay \(\psi(3686) \to e^+ e^- \eta_c\) with a significance of \(7.9\sigma\). The branching fraction is determined to be \(\mathcal{B} (\psi(3686) \to e^+ e^- \eta_c) = (3.77 \pm 0.40_{\rm stat.} \pm 0.18_{\rm syst.})\times 10^{-5}\), agreeing well with the prediction of the vector meson dominance model. This is the first measurement of the electromagnetic Dalitz transition between the \(\psi(3686)\) and the \(\eta_c\), which provides new insight into the electromagnetic properties of this decay, and offers new opportunities to measure the absolute branching fractions of \(\eta_c\) decays.
Using data samples with a total integrated luminosity of approximately 18 fb\(^{-1}\) collected by the BESIII detector operating at the BEPCII, the process \(e^+e^-\rightarrow\Lambda\bar{\Lambda} ...\eta\) is studied at center-of-mass energies between 3.5106 and 4.6988 GeV. The Born cross section for the process \(e^+e^-\rightarrow\Lambda\bar{\Lambda}\eta\) is measured. No significant structure is observed in the Born cross section line shape. An enhancement near the \(\Lambda\bar{\Lambda}\) mass threshold is observed for the first time in the process. The structure can be described by an \(S\)-wave Breit-Wigner function. Neglecting contribution of excited \(\Lambda\) states and potential interferences, the mass and width are determined to be (\(2356\pm 7\pm17\)) MeV/\(c^2\) and (\(304\pm28\pm54\)) MeV, respectively, where the first uncertainties are statistical and the second are systematic.
: Vibriosis is an economically important disease of fish, marine invertebrates (particularly penaeid shrimps), and large marine mammals and is responsible for high mortality rates in aquaculture ...worldwide. Some Vibrio species are also responsible for zoonoses, whereas others are relatively nonpathogenic. Using 16S‐ and 23S‐based PCR reactions, we obtained species‐specific patterns and a 470‐bp band, respectively. DNA sequences obtained on the 23S rRNA gene allowed us to identify species‐specific probes for Vibrio parahaemolyticus, V. alginolyticus, V. anguillarum and for a cluster of taxonomically related species: V. carchariae/harveyi/campbelii. A phylogenetic tree based on the 23S sequences confirmed previous results obtained by Western blotting.
A series of nanocomposites that consisted of the emeraldine salt of polyaniline and layered vermiculite were prepared. The vermiculite was first delaminated with acid treatment, and then the ...polyaniline/vermiculite nanocomposites were prepared via in situ polymerization of monomers in the presence of vermiculite sheets. The as-synthesized polyaniline/vermiculite nanocomposite materials were characterized by infrared spectroscopy, transmission electron microscopy, electrical conductivity measurement, and thermogravimetric analysis. Thermal analyses indicated that the introduction of vermiculite nanosheets showed a beneficial effect on the thermal stability of polyaniline.
We search for an axion-like particle (ALP) \(a\) through the process \(\psi(3686)\rightarrow\pi^+\pi^-J/\psi\), \(J/\psi\rightarrow\gamma a\), \(a\rightarrow\gamma\gamma\) in a data sample of ...\((2.71\pm0.01)\times10^9\) \(\psi(3686)\) events collected by the BESIII detector. No significant ALP signal is observed over the expected background, and the upper limits on the branching fraction of the decay \(J/\psi\rightarrow\gamma a\) and the ALP-photon coupling constant \(g_{a\gamma\gamma}\) are set at 95% confidence level in the mass range of \(0.165\leq m_a\leq2.84\,\mbox{GeV}/c^2\). The limits on \(B(J/\psi\rightarrow\gamma a)\) range from \(8.3\times10^{-8}\) to \(1.8\times10^{-6}\) over the search region, and the constraints on the ALP-photon coupling are the most stringent to date for \(0.165\leq m_a\leq1.468\,\mbox{GeV}/c^2\).
