2,511 research outputs found

    The main issues of globalization

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    Phylogenetic relationships within Orobanche and Phelipanche (Orobanchaceae) from Central Europe, focused on problematic aggregates, taxonomy, and host ranges

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    Holoparasitic genera within the family Orobanchaceae are characterized by greatly reduced vegetative organs; therefore, molecular analysis has proved to be a useful tool in solving taxonomic problems in this family. For this purpose, we studied all species of the genera Orobanche and Phelipanche occurring in Central Europe, specifically in Poland, the Czech Republic, Slovakia, and Austria, supplemented by samples mainly from Spain, France, Germany, and Ukraine. They were investigated using nuclear sequences (ITS region) and a plastid trnL- trnF region. The aim of this study was to examine phylogenetic relationships within Orobanche and Phelipanche from Central Europe; we focused on problematic species and aggregates, recent taxonomic changes in these (rank and secondary ranks), and host ranges. The most interesting results concern the exlusion of O. mayeri from O. alsatica aggr. Additionally, following the rules of traditional taxonomy, the correct names and types of some secondary ranks are given and, as a result of this, a new combination below the Phelipanche genus is made ( P . sect. Trionychon ). The host ranges of the investigated species in Central Europe include 102 species from 12 families, most often from Asteraceae. For this purpose, ca. 400 localities were examined in the field. Moreover, data acquired from the literature and European and Asian herbaria were use

    Observation of a charged charmoniumlike structure in e+e(DDˉ)±πe^+e^- \to (D^{*} \bar{D}^{*})^{\pm} \pi^\mp at s=4.26\sqrt{s}=4.26GeV

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    We study the process e+e(DDˉ)±πe^+e^- \to (D^{*} \bar{D}^{*})^{\pm} \pi^\mp at a center-of-mass energy of 4.26GeV using a 827pb1^{-1} data sample obtained with the BESIII detector at the Beijing Electron Positron Collider. Based on a partial reconstruction technique, the Born cross section is measured to be (137±9±15)(137\pm9\pm15)pb. We observe a structure near the (DDˉ)±(D^{*} \bar{D}^{*})^{\pm} threshold in the π\pi^\mp recoil mass spectrum, which we denote as the Zc±(4025)Z^{\pm}_c(4025). The measured mass and width of the structure are (4026.3±2.6±3.7)(4026.3\pm2.6\pm3.7)MeV/c2^2 and (24.8±5.6±7.7)(24.8\pm5.6\pm7.7)MeV, respectively. Its production ratio σ(e+eZc±(4025)π(DDˉ)±π)σ(e+e(DDˉ)±π)\frac{\sigma(e^+e^-\to Z^{\pm}_c(4025)\pi^\mp \to (D^{*} \bar{D}^{*})^{\pm} \pi^\mp)}{\sigma(e^+e^-\to (D^{*} \bar{D}^{*})^{\pm} \pi^\mp)} is determined to be 0.65±0.09±0.060.65\pm0.09\pm0.06. The first uncertainties are statistical and the second are systematic.Comment: 7 pages, 4 figures, 1 table; version accepted to be published in PR

    Search for the Lepton Flavor Violation Process J/ψeμJ/\psi \to e\mu at BESIII

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    We search for the lepton-flavor-violating decay of the J/ψJ/\psi into an electron and a muon using (225.3±2.8)×106(225.3\pm2.8)\times 10^{6} J/ψJ/\psi events collected with the BESIII detector at the BEPCII collider. Four candidate events are found in the signal region, consistent with background expectations. An upper limit on the branching fraction of B(J/ψeμ)<1.5×107\mathcal{B}(J/\psi \to e\mu)< 1.5 \times 10^{-7} (90% C.L.) is obtained

    Measurement of azimuthal asymmetries in inclusive charged dipion production in e+ee^+e^- annihilations at s\sqrt{s} = 3.65 GeV

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    We present a measurement of the azimuthal asymmetries of two charged pions in the inclusive process e+eππXe^+e^-\rightarrow \pi\pi X based on a data set of 62 pb1\rm{pb}^{-1} at the center-of-mass energy s=3.65\sqrt{s}=3.65 GeV collected with the BESIII detector. These asymmetries can be attributed to the Collins fragmentation function. We observe a nonzero asymmetry, which increases with increasing pion momentum. As our energy scale is close to that of the existing semi-inclusive deep inelastic scattering experimental data, 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 spin-dependent fragmentation function.Comment: 7 pages, 5 figure

    Observation of J/ψppˉa0(980)J/\psi \rightarrow p\bar{p}a_{0}(980) at BESIII

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    Using 2.25×1082.25\times10^{8} J/ψJ/\psi events collected with the BESIII detector at the BEPCII storage rings, we observe for the first time the process J/ψppˉa0(980)J/\psi\rightarrow p\bar{p}a_{0}(980), a0(980)π0ηa_{0}(980)\rightarrow \pi^{0}\eta with a significance of 6.5σ6.5\sigma (3.2σ3.2\sigma including systematic uncertainties). The product branching fraction of J/ψppˉa0(980)ppˉπ0ηJ/\psi\rightarrow p\bar{p}a_{0}(980)\rightarrow p\bar{p}\pi^{0}\eta is measured to be (6.8±1.2±1.3)×105(6.8\pm1.2\pm1.3)\times 10^{-5}, where the first error is statistical and the second is systematic. This measurement provides information on the a0a_{0} production near threshold coupling to ppˉp\bar{p} and improves the understanding of the dynamics of J/ψJ/\psi decays to four body processes.Comment: 8 pages, 7 figure

    Measurement of the e+eηJ/ψe^{+}e^{-} \to \eta J/\psi cross section and search for e+eπ0J/ψe^{+}e^{-} \to \pi^{0} J/\psi at center-of-mass energies between 3.810 and 4.600~GeV

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    Using data samples collected with the BESIII detector operating at the BEPCII collider at center-of-mass energies from 3.810 to 4.600 GeV, we perform a study of e+eηJ/ψe^{+}e^{-} \to \eta J/\psi and π0J/ψ\pi^0 J/\psi. Statistically significant signals of e+eηJ/ψe^{+}e^{-} \to \eta J/\psi are observed at s\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+eπ0J/ψe^{+}e^{-} \to \pi^{0} J/\psi are observed. The measured energy-dependent Born cross section for e+eηJ/ψe^{+}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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