The process e+e−→K+K−η has been studied in the center-of-mass energy range from 1.59 to 2.007 GeV using the data sample of 59.5 pb−1, collected with the CMD-3 detector at the VEPP-2000 e+e− collider ...in 2011, 2012 and 2017. The K+K−η final state is found to be dominated by the contribution of the ϕ(1020)η intermediate state. The cross section of the process e+e−→ϕ(1020)η has been measured with a systematic uncertainty of 5.1% on the base of 3009 ± 67 selected events. The obtained cross section has been used to calculate the contribution to the anomalous magnetic moment of the muon: aμϕη(E<1.8GeV)=(0.321±0.015stat±0.016syst)×10−10, aμϕη(E<2.0GeV)=(0.440±0.015stat±0.022syst)×10−10. From the cross section approximation the ϕ(1680) meson parameters have been determined with better statistical precision, than in previous studies.
The main principles of using wires with tungsten nanopowder for arc cladding are considered. Special features of production and application of tungsten-modified wires are analyzed. The microstructure ...of the high-strength layer obtained by cladding wires with different tungsten nanopowder contents is investigated. Microhardness of clad specimens is determined.
Abstract We describe the recently discovered phenomenon of the formation of an extended luminous structure at the bend of the channel of a high-voltage pulse discharge. It is called the apokamp (from ...the Greek words απó — ‘from’ and κάμπη — ‘bend’), and the discharge as a whole is referred to as apokampic. In the course of experimental and theoretical studies, it is shown that the apokamp is a narrow streamer channel that propagates at a characteristic speed of tens to hundreds of km/s, depending on the applied voltage, pressure, and gas type. The necessary conditions for apokamp formation are established. The apokamp discharge is used for laboratory studies of conditions for the formation of blue jets and red sprites — large-scale transient luminous events (transients) observed in Earth’s atmosphere above areas with thunderstorm activity. The revealed signs of similarity between apokamps and blue jets are described. The proposed experimental setup can also be used for meaningful testing of hypotheses about the conditions of formation of transients in Earth’s atmosphere and in the atmospheres of other planets.
The process e+e−→K+K−π+π− has been studied in the center-of-mass energy range from 1500 to 2000 MeV using a data sample of 23 pb−1 collected with the CMD-3 detector at the VEPP-2000 e+e− collider. ...Using about 24 000 selected events, the e+e−→K+K−π+π− cross section has been measured with a systematic uncertainty decreasing from 11.7% at 1500–1600 MeV to 6.1% above 1800 MeV. A preliminary study of K+K−π+π− production dynamics has been performed.
Recent results from the CMD-3 detector Lukin, P.A.; Akhmetshin, R.R.; Amirkhanov, A.N. ...
Nuclear and particle physics proceedings,
January-March 2020, 2020-01-00, Letnik:
309-311
Journal Article
Recenzirano
This paper reports a current status of the measurements of the hadronic cross sections in the c.m. energy range from 0.32 to 2.0 GeV with the CMD-3 detector at the VEPP-2000 electron-positron ...collider. The overall size of the data, acquired by the CMD-3 in the runs of 2010–2013 and 2017–2018 years, is about 160 pb−1. The results of data analysis for various exclusive modes of e+e−→hadrons are described.
Aspects of obtaining electrodes with a coating containing tungsten nanopowder are considered along with their modes of utilization for surfacing purposes. The rheological properties of an aqueous ...alkaline solution of potassium silicate used for applying tungsten nanopowder to electrodes are determined. The stability of the surfacing process is investigated in terms of the structure of the metal deposited with coated electrodes. It is confirmed that coating electrodes with tungsten nanopowder can be used to derive a stable process of transferring droplets of electrode metal into the melt bath and modifying the deposited metal by influencing the viscosity of the coating of combined electrodes.
We study the process e + e − → e + e − η ′ in the double-tag mode and measure for the first time the γ * γ * → η ′ transition form factor F η′ ( Q 2 1 , Q 2 2 ) in the momentum-transfer range 2 < Q 2 ...1 , Q 2 2 < 60 GeV 2 . The analysis is based on a data sample corresponding to an integrated luminosity of around 469 fb − 1 collected at the PEP-II e + e − collider with the BABAR detector at center-of-mass energies near 10.6 GeV.
We study the process e+e−→π+π−ηγ, where the photon is radiated from the initial state. About 8000 fully reconstructed events of this process are selected from the BABAR data sample with an integrated ...luminosity of 469 fb−1. Using the π+π−η invariant mass spectrum, we measure the e+e−→π+π−η cross section in the e+e− center-of-mass energy range from 1.15 to 3.5 GeV. The cross section is well described by the Vector-Meson dominance model with four ρ-like states. We observe 49±9 events of the J/ψ decay to π+π−η and measure the product ΓJ/Ψ→e+e−BJ/Ψ→π+π−η=2.34±0.43stat±0.16syst eV.
Axionlike particles (ALPs) are predicted in many extensions of the standard model, and their masses can naturally be well below the electroweak scale. In the presence of couplings to electroweak ...bosons, these particles could be emitted in flavor-changing B meson decays. We report herein a search for an ALP, a, in the reaction B^{±}→K^{±}a, a→γγ using data collected by the BABAR experiment at SLAC. No significant signal is observed, and 90% confidence level upper limits on the ALP coupling to electroweak bosons are derived as a function of ALP mass, improving current constraints by several orders of magnitude in the range 0.175 GeV<m_{a}<4.78 GeV.
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