# Vorabdrucke

Letzte Einträge:
 2021-01-2622:16 [GSI-2021-00221] Preprint Soloveva, O. ; Fuseau, D. ; Aichelin, J. ; et al Shear viscosity and electric conductivity of a hot and dense QGP with a chiral phase transition [2011.03505] We calculate two transport coefficients -- the shear viscosity over entropy ratio $\eta/s$ and the ratio of the electric conductivity to the temperature $\sigma_0/T$ -- of strongly interacting quark matter within the extended $N_f=3$ Polyakov Nambu-Jona-Lasinio (PNJL) model along the crossover transition line for moderate values of baryon chemical potential $0 \leq \mu_B \leq 0.9$ GeV as well as in the vicinity of the critical endpoint (CEP) and at large baryon chemical potential $\mu_B=1.2$ GeV, where the first-order phase transition takes place. The evaluation of the transport coefficients is performed on the basis of the effective Boltzmann equation in the relaxation time approximation. [...] 2021-01-2621:36 [GSI-2021-00216] Preprint Song, T. ; Tolos, L. ; Wirth, J. ; et al In-medium effects in strangeness production in heavy-ion collisions at (sub-)threshold energies We study the in-medium effects in strangeness production in heavy-ion collisions at (sub-)\-threshold energies of 1 - 2 A GeV based on the microscopic Parton-Hadron-String Dynamics (PHSD) transport approach. The in-medium modifications of the antikaon $(\bar K = K^-, \bar K^0)$ properties are described via the self-consistent coupled-channel unitarized scheme based on a SU(3) chiral Lagrangian which incorporates explicitly the $s-$ and $p-$ waves of the kaon-nucleon interaction. [...] 2021-01-1514:43 [GSI-2021-00100] Preprint GlueX Collaboration ; Adhikari, S. ; Akondi, C. S. ; et al Measurement of beam asymmetry for $\pi^-\Delta^{++}$ photoproduction on the proton at $E_\gamma$=8.5 GeV [GlueX-Doc 4272] We report a measurement of the $\pi^-$ photoproduction beam asymmetry for the reaction $\vec{\gamma} p \rightarrow \pi^- \Delta^{++}$ using data from the GlueX experiment in the photon beam energy range 8.2--8.8 GeV. The asymmetry $\Sigma$ is measured as a function of four-momentum transfer $t$ to the $\Delta^{++}$ and compared to phenomenological models. [...] 2021-01-1415:35 [GSI-2021-00094] Preprint BESIII Collaboration ; Ablikim, M. ; Achasov, M. N. ; et al Measurement of the absolute branching fraction of $\Lambda_c^+\to p K^0_{\mathrm{S}}\eta$ decays Based on 586 $\rm{pb^{-1}}$ of $e^+e^-$ annihilation data collected at a center-of-mass energy of $\sqrt{s}=4.6~\rm{GeV}$ with the BESIII detector at the BEPCII collider, the absolute branching fraction of $\Lambda_c^+ \to p K^0_{\mathrm{S}}\eta$ decays is measured for the first time to be $\mathcal{B}(\Lambda_c^+ \to p K^0_{\mathrm{S}}\eta) = (0.414 \pm 0.084 \pm 0.028)\%$, where the first uncertainty is statistical and the second is systematic. The result is compatible with a previous CLEO result on the relative branching fraction $\frac{\mathcal{B}(\Lambda_c^+ \to p K^0_{\mathrm{S}}\eta)}{\mathcal{B}(\Lambda_c^+ \to p K^-\pi^+)}$, and consistent with theoretical predictions of SU(3) flavor symmetry.. 2021-01-1415:33 [GSI-2021-00093] Preprint BESIII Collaboration ; Ablikim, M. ; Achasov, M. N. ; et al Measurement of the Born cross sections for $e^+e^- \to \eta^\prime \pi^{+}\pi^{-}$ at center-of-mass energies between $2.00$ and $3.08$~GeV The Born cross sections for the process $e^+e^- \to \eta^\prime \pi^{+}\pi^{-}$ at different center-of-mass energies between $2.00$ and $3.08$~GeV are reported with improved precision from an analysis of data samples collected with the BESIII detector operating at the BEPCII storage ring. An obvious structure is observed in the Born cross section line shape. [...] 2021-01-1415:29 [GSI-2021-00092] Preprint BESIII Collaboration ; Ablikim, M. ; Achasov, M. N. ; et al Search for the $X(2370)$ and observation of $\eta_{c}\to\eta\eta\eta^\prime$ in $J/\psi\to\gamma\eta\eta\eta^{\prime}$ Using a sample of $1.31\times10^{9} ~J/\psi$ events collected with the BESIII detector, we perform a study of $J/\psi\to\gamma\eta\eta\eta^{\prime}$ to search for the $X(2370)$ and $\eta_{c}$ in the $\eta\eta\eta^{\prime}$ invariant mass distribution. No significant signal for the $X(2370)$ is observed, and we set an upper limit for the product branching fraction of ${\cal B}(J/\psi\to\gamma X(2370)\cdot{\cal B}(X(2370)\to\eta\eta\eta^{\prime}) < 9.2\times10^{-6}$ at the 90% confidence level. [...] 2021-01-1415:27 [GSI-2021-00091] Preprint BESIII Collaboration ; Ablikim, M. ; Achasov, M. N. ; et al Observation of $\eta^\prime\rightarrow\pi^+\pi^-\mu^+\mu^-$ Using $(1310.6 \pm 7.0) \times 10^{6}~J/\psi$ events acquired with the BESIII detector at the BEPCII storage rings, the decay $\eta^\prime\rightarrow\pi^+\pi^-\mu^+\mu^-$ is observed for the first time with a significance of 8$\sigma$ via the process $J/\psi\rightarrow\gamma\eta'$. We measure the branching fraction of $\eta^\prime\rightarrow\pi^+\pi^-\mu^+\mu^-$ to be $\mathcal{B}(\eta^\prime\rightarrow\pi^+\pi^-\mu^+\mu^-)$=(1.97$\pm$0.33(stat.)$\pm$0.18(syst.))$\times10^{-5}$, where the first and second uncertainties are statistical and systematic, respectively.. 2021-01-1415:24 [GSI-2021-00090] Preprint BESIII Collaboration ; Ablikim, M. ; Achasov, M. N. ; et al Search for the lepton number violating decay $\Sigma^{-} \to p e^{-} e^{-}$ and the rare inclusive decay $\Sigma^{-} \to \Sigma^{+} X$ Using a data sample of $(1310.6 \pm 7.0) \times 10^{6}$ $J/\psi$ events taken with the BESIII detector at the center-of-mass energy of 3.097 GeV, we search for the first time for the lepton number violating decay $\Sigma^{-} \to p e^{-} e^{-}$ and the rare inclusive decay $\Sigma^{-} \to \Sigma^{+} X$, where $X$ denotes any possible particle combination. The $\Sigma^-$ candidates are tagged in $J/\psi \to \bar{\Sigma}(1385)^+\Sigma^-$ decays. [...] 2021-01-1415:21 [GSI-2021-00089] Preprint BESIII Collaboration ; Ablikim, M. ; Achasov, M. N. ; et al Search for the reaction $e^{+}e^{-} \rightarrow \pi ^{+}\pi ^{-} \chi_{cJ}$ and a charmonium-like structure decaying to $\chi_{cJ}\pi ^{\pm}$ between 4.18 and 4.60 GeV We search for the process $e^{+}e^{-}\rightarrow \pi ^{+}\pi ^{-} \chi_{cJ}$ ($J=0,1,2$) and for a charged charmonium-like state in the $\pi ^{\pm} \chi_{cJ}$ subsystem. The search uses data sets collected with the BESIII detector at the BEPCII storage ring at center-of-mass energies between 4.18 GeV and 4.60 GeV. [...] 2021-01-1415:15 [GSI-2021-00088] Preprint BESIII Collaboration ; Ablikim, M. ; Achasov, M. N. ; et al Search for the reaction channel $e^+e^- \rightarrow \eta_c\eta \pi^+\pi^-$ at center-of-mass energies from 4.23 to 4.60 GeV Using data collected with the BESIII detector operating at the Beijing Electron Positron Collider, we search for the process $e^+e^-\rightarrow \eta_c\eta \pi^+\pi^-$. The search is performed using five large data sets recorded at center-of-mass energies of 4.23, 4.26, 4.36, 4.42, and 4.60 GeV. [...]