Vorabdrucke

Letzte Einträge:
 2019-01-0411:25 [GSI-2019-00044] Preprint et al Measurement of $\mathcal{B}(J/\psi \to \eta' e^+ e^-$) and search for dark photon Using a data sample of $(1310.6\pm7.0)\times10^{6}$ $J/\psi$ events collected with the BESIII detector at BEPCII, we study the electromagnetic Dalitz decay $J/\psi \to \eta' e^+e^-$ with two dominant $\eta'$ decay modes, $\eta' \to \gamma \pi^+ \pi^-$ and $\eta' \to \pi^+\pi^-\eta$. The branching fraction is determined to be $\mathcal{B}(J/\psi \to \eta' e^+e^-) = (6.79 \pm 0.08\pm 0.35)\times10^{-5}$, which supersedes the previous BESIII measurement. [...] 2019-01-0411:22 [GSI-2019-00043] Preprint et al Polarization and Entanglement in Baryon-Antibaryon Pair Production in Electron-Positron Annihilation Using a sample of $1.31\times 10^9$ $J/\psi$ events collected with the BESIII detector, we report the first observation of spin polarization of $\Lambda$ and $\bar\Lambda$ hyperons from the coherent production in the $J/\psi\to\Lambda\bar\Lambda$ decay. We measure the phase between the hadronic form factors to be $\Delta\Phi=(42.4\pm0.6\pm0.5)^\circ$. [...] 2019-01-0411:09 [GSI-2019-00042] Preprint et al Precision measurements of $\sigma_{B}(e^+e^- \to K_{S}^{0}K^{\pm}\pi^{\mp})$ at center-of-mass energies between 3.8 and 4.6 GeV Using data samples collected by the BESIII detector operating at BEPCII with center-of-mass energies between 3.8 and 4.6\,GeV and with a total luminosity of about 5.0~fb$^{-1}$, we measure the Born cross sections of $e^+e^- \to K_{S}^{0}K^{\pm}\pi^{\mp}$, $\sigma_{B}(e^+e^- \to K_{S}^{0}K^{\pm}\pi^{\mp})$. The cross sections are generally smaller than those of BABAR but with significantly improved precision. [...] 2019-01-0410:42 [GSI-2019-00038] Preprint et al Evidence of a resonant structure in the $e^+e^-\to \pi^+D^0D^{*-}$ cross section between 4.05 and 4.60 GeV The cross section of the process $e^+e^-\to \pi^+D^0D^{*-}$ for center-of-mass energies from 4.05 to 4.60~GeV is measured precisely using data samples collected with the BESIII detector operating at the BEPCII storage ring. Two enhancements are clearly visible in the cross section around 4.23 and 4.40~GeV. [...] 2019-01-0410:34 [GSI-2019-00037] Preprint et al Measurement of the phase between strong and electromagnetic amplitudes of $J/\psi$ decays Using 16 points of $e^{+}e^{-}$ annihilation data collected in the vicinity of the $J/\psi$ resonance with the BESIII detector and with a total integrated luminosity of around 100 pb$^{-1}$, we study the relative phase between the strong and electromagnetic amplitudes of $J/\psi$ decays. The relative phase between the $J/\psi$ electromagnetic decay and the continuum process ($e^{+}e^{-}$ annihilation without the $J/\psi$ resonance) is confirmed to be zero by studying the Born cross section lineshape of $\mu^{+}\mu^{-}$ production. [...] 2019-01-0313:42 [GSI-2019-00025] Preprint et al Search for Baryon and Lepton Number Violation in $J/\psi\to\Lambda_c^+e^-+c.c.$ Using $1.31\times10^9$ $J/\psi$ events collected by the BESIII detector at the Beijing Electron Positron Collider, we search for the process $J/\psi\to\Lambda_c^+e^-+c.c.$ for the first time. In this process, both baryon and lepton number conservation is violated. [...] 2019-01-0214:45 [GSI-2019-00005] Preprint et al Search for a strangeonium-like structure $Z_s$ decaying into $\phi \pi$ and a measurement of the cross section $e^+e^-\rightarrow\phi\pi\pi$ Using a data sample of $e^+e^-$ collision data corresponding to an integrated luminosity of 108 pb$^{-1}$ collected with the BESIII detector at a center-of-mass energy of 2.125 GeV, we study the process $e^+e^-\rightarrow \phi\pi\pi$, and search for a strangeonium-like structure $Z_s$ decaying into $\phi \pi$. No signal is observed in the $\phi\pi$ mass spectrum. [...] 2018-08-1309:16 [GSI-2018-00899] Preprint/Report Chung, M. Relation between particle beam eigen-emittances and canonical vorticity flux [arXiv:1808.01218] 4 p. (2018) Particle beams provided by accelerators occupy a finite volume of the four dimensional transverse phase space. The latter is spanned by the four degrees of freedom, i.e., horizontal/vertical position and momentum. [...] 2017-04-2513:57 [GSI-2017-00656] Preprint/Report Typel, S. Comparison of equation of state models with different cluster dissolution mechanisms [arXiv:1612.07022] The appearance of nuclear clusters in stellar matter at densities below nuclear saturation is an important feature in the modeling of the equation of state for astrophysical applications. There are different theoretical concepts to describe the dissolution of nuclei with increasing density and temperature. [...] 2017-01-3116:09 [GSI-2017-00323] Preprint et al Feasibility studies of time-like proton electromagnetic form factors at PANDA at FAIR Simulation results for future measurements of electromagnetic proton form factors at \PANDA (FAIR) within the PandaRoot software framework are reported. The statistical precision with which the proton form factors can be determined is estimated. [...]