Abstract Using data samples with an integrated luminosity of 6.4 fb −1 collected by the BESIII detector operating at the BEPCII storage ring, the process of e + e − → γϕJ/ψ is studied. The processes ...of e + e − → ϕχ c1, c2, χ c1, c2 → γJ/ψ are observed with a significance of more than 10σ. The s $$ \sqrt{s} $$ -dependent cross section of e + e − → ϕχ c1, c2 is measured between 4.600 and 4.951 GeV, and evidence of a resonance structure is found for the first time in the ϕχ c2 process. We also search for the processes of e + e − → γX(4140), γX(4274) and γX(4500) via the γϕJ/ψ final state, but no obvious structures are found. The upper limits on the production cross section times the branching fraction for these processes at the 90% confidence level are reported.
•We have synthesized large sized and high-quality single crystals of NiWO4.•Magnetic anisotropy was studied on single crystals by magnetic susceptibility.•Magnetization was measured in magnetic ...fields up to 30T and the spin-flop transition was observed in the vicinity of 17.5T.
NiWO4 exhibits a spin chain structure built by magnetic Ni2+ ions, which may be considered as a one dimensional S=1 system. In this work, large-sized single crystals of NiWO4 were successfully synthesized by a flux method and the crystal quality was confirmed by X-ray diffraction. Magnetic properties of obtained single crystals were studied by means of magnetic susceptibility and high field magnetization along crystallographic axes. The results demonstrate that NiWO4 is highly magnetic anisotropic and possesses a three-dimensional long range ordering below 60K, where a spin flop transition can be observed at 17.5T in applied magnetic fields along the magnetic easy axis (c-axis).
MicroRNAs (miRNAs) are a class of small non-encoding RNAs that regulate gene expression at the posttranscriptional level. MiRNAs may characterize not only specific stages of the development of the ...neural cell population in CNS, but also distinct types of neural cells. However, the common pathways of the neural enriched miRNAs involved in neurogenesis of specific cell lineages remain poorly understood. In this report, in order to get insights into the common role of the miRNAs shared by cerebellum and forebrain, we studied the regulatory mechanism of neural enriched-miRNA in neural progenitor cell (NPCs) differentiation. Here, we identified a new cerebellum-enriched rno-miR-592 in rat cerebellum. It showed that rno-miR-592 was a neural enriched miRNA and may play an important role in rat embryonic neurogenesis or/and astrogliogenesis. We used both gain-of -function and loss-of -function approaches to demonstrate that rno-miR-592 could change the balance between neuron- and astrocyte- like differentiation and neuronal morphology. We observed that miR-592 could induce astrogliogenesis differentiation arrest or/and enhance neurogenesis in vitro. Meanwhile, silencing of miR-592 was not beneficial for neuronal maturation. We also identified Lrrc4c and Nfasc as miR-592 target genes, and miR-592 could affect the changes of Lrrc4c and Nfasc expression levels, suggesting that these two target genes may be involved in miR-592 regulative function in NPCs differentiation and neuronal maturation. Thus, we conclude that rno-miR-592 may affect the neural lineage differentiation via reducing astrogliogenesis or/and enhancing neurogenesis at least in part through regulating its target genes Lrrc4c and Nfasc in vitro. Together, we report here for the first time the important role of miR-592 in rat NPCs differentiation and neuronal maturation.
Charge eXchange Recombination Spectroscopy (CXRS) systems have been successfully applied on EAST since 2014. However, geometrical effects will deteriorate the diagnostic locality and introduce ...uncertainties into the measurement. A simplified spatial average model for the average of effective integral paths and an upgraded simulation of spectra (SOS) code are both used to evaluate these geometrical effects. The results show that spatial averaging effect with one beam can introduce up to ˜10% relative error in the ion temperature and velocity measurement at ITB region. Simultaneous injection of two beams can produce ˜20% uncertainties in core CXRS with single gaussian description of the spectra. To reduce the error, the spatial averaged position ρav calculated from the simplified model and a double gaussians fitting with a constrained intensity ratio model are applied in the CXRS data analysis, and the fitting results show a good consistency with the input profiles.
The effect of sheared E × B flow on the blob dynamics in the scrape-off layer (SOL) of HL-2A tokamak has been studied during the plasma current ramp-up in ohmically heated deuterium plasmas by the ...combination of poloidal and radial Langmuir probe arrays. The experimental results indicate that the SOL sheared E × B flow is substantially enhanced as the plasma current exceeds a certain value and the strong sheared E × B flow has the ability to slow the blob radial motion via stretching its poloidal correlation length. The locally accumulated blobs are suggested to be responsible for the increase of plasma density just outside the Last Closed Flux Surface (LCFS) observed in this experiment. The results presented here reveal the significant role played by the strong sheared E × B flow on the blob dynamics, which provides a potential method to control the SOL width by modifying the sheared E × B flow in future tokamak plasmas.
A search for the rare radiative leptonic decay Ds+ → γe+νe is performed for the first time using electron-positron collision data corresponding to an integrated luminosity of 3.19 fb–1, collected ...with the BESIII detector at a center-of-mass energy of 4.178 GeV. No evidence for the Ds+ → γe+νe decay is seen, and an upper limit of B( Ds+ → γe+νe ) < 1.3 ×10–4 is set on the partial branching fraction at a 90% confidence level for radiative photon energies $E$ $^{*}_{γ}$ > 0.01 GeV.
The baryonic decay D$+\atop{s}$→p$\overline{n}$ is examined, and the corresponding branching fraction is measured to be (1.21 ± 0.10 ± 0.05 ) × 10-3 , where the first uncertainty is statistical and ...second systematic. The data sample used in this analysis was collected with the BESIII detector operating at the BEPCII e+e- double-ring collider with a center-of-mass energy of 4.178 GeV and an integrated luminosity of 3.19 fb-1 . The result corroborates the previous measurement by the CLEO Collaboration and is of greatly improved precision. This result will improve our understanding of the dynamical enhancement of the W-annihilation topology in the charmed meson decays.
•The beam emission spectroscopy (BES) system has recently been upgraded and operated successfully in the 2018 experimental campaign on EAST.•A curved mask strip manufactured by photolithography ...technology suppresses the intense edge Dα line.•Efficiency of curved strip and performances of BES spectrometer are calibrated using the integrating sphere and spectral lamps respectively.•The beam emission spectral lines and active charge exchange line emitted by main ions are measured simultaneously.
The beam emission spectroscopy (BES) system that shares the collection optics with the core charge exchange recombination spectroscopy (cCXRS) has recently been upgraded on EAST. The enhanced system aims at the simultaneous measurements of the neutral beam emission from the co-current and counter-current neutral beam injection (NBI) as well as the active charge exchange line (Dα, n = 3→2, 656.1 nm) from the interaction of the main ions and the injected neutral beam. The operating spectral band of the system is 656.1 ± 6 nm, with respect to the maximum Doppler shift and stark splitting induced by the highest energy of 80 keV for deuterium beam. Strong edge Dα line is effectively suppressed by one curved chromate strip (˜3% transmission and ˜83 μm width) on the fused silica. Main ion Dα emission and beam emission spectra are acquired simultaneously without any saturation of the signal on the detector. In this paper, an overview of the upgraded spectrometer will be shown and the first experimental results are presented.
Abstract Using e + e − annihilation data corresponding to a total integrated luminosity of 6.32 fb −1 collected at the center-of-mass energies between 4.178 and 4.226 GeV with the BESIII detector, we ...perform an amplitude analysis of the decay D s + $$ {D}_s^{+} $$ → K − K + π + π + π − and determine the relative fractions and phases of different intermediate processes. Absolute branching fraction of D s + $$ {D}_s^{+} $$ → K − K + π + π + π − decay is measured to be (6.60 ± 0.47stat. ± 0.38syst. ) × 10 −3. The dominant intermediate process is D s + $$ {D}_s^{+} $$ → a 1(1260)+ ϕ, ϕ → K − K + , a 1(1260)+ → ρπ + , ρ → π + π − , with a branching fraction of (5.15 ± 0.41stat. ± 0.32syst. ) × 10 −3.
We present an analysis of the process ψ(3686)→Ω^{-}Ωover ¯^{+} (Ω^{-}→K^{-}Λ, Ωover ¯^{+}→K^{+}Λover ¯, Λ→pπ^{-}, Λover ¯→pover ¯π^{+}) based on a dataset of 448×10^{6} ψ(3686) decays collected with ...the BESIII detector at the BEPCII electron-positron collider. The helicity amplitudes for the process ψ(3686)→Ω^{-}Ωover ¯^{+} and the decay parameters of the subsequent decay Ω^{-}→K^{-}Λ (Ωover ¯^{+}→K^{+}Λover ¯) are measured for the first time by a fit to the angular distribution of the complete decay chain, and the spin of the Ω^{-} is determined to be 3/2 for the first time since its discovery more than 50 years ago.
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