The cross section of the process e + e − → π + π − has been measured in the center of mass energy range from 0.32 to 1.2 GeV with the CMD-3 detector at the electron-positron collider VEPP-2000. The ...measurement is based on a full dataset collected below 1 GeV during three data taking seasons, corresponding to an integrated luminosity of about 62 pb − 1 . In the dominant ρ -resonance region, a systematic uncertainty of 0.7% has been reached. At energies around ϕ -resonance the π + π − production cross section was measured for the first time with high beam energy resolution. The forward-backward charge asymmetry in the π + π − production has also been measured. It shows a strong deviation from the theoretical prediction based on the conventional scalar quantum electrodynamics framework, and it is in good agreement with the generalized vector-meson-dominance and dispersive-based predictions. The impact of the presented results on the evaluation of the hadronic contribution to the anomalous magnetic moment of muon is discussed. Published by the American Physical Society 2024
We report on the progress in development of a highly accurate optical frequency standard based on the single ion of ytterbium-171 at the Institute of Laser Physics, Novosibirsk.
Drift chamber for the CMD-3 detector Grancagnolo, F.; Fiore, G.; Ignatov, F.V. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
11/2010, Volume:
623, Issue:
1
Journal Article
Peer reviewed
The construction, digitizing electronics and results of test with cosmic rays of cylindrical drift chamber for CMD-3 detector are described. To uniformly fill the sensitive volume small hexagonal ...cells were chosen. The coordinate along the wire is measured by charge division technique. A resolution in the R–ϕ-plane of better than 110μm and about 3mm along the wire as well as a dE/dx resolution of about 12% were obtained in cosmic test runs.
The process e+e−→ϕ→K+K− has been studied with the CMD-2 detector using about 542 000 events detected in the center-of-mass energy range from 1.01 to 1.034 GeV. The systematic error of the cross ...section is estimated to be 2.2%. The ϕ(1020) meson parameters in the ϕ→K+K− decay channel have been measured: σ0(ϕ→K+K−)=2016±8±44 nb, mϕ=1019.441±0.008±0.080 MeV/c2, Γϕ=4.24±0.02±0.03 MeV, Be+e−BK+K−=(14.27±0.05±0.31)×10−5.
In the process of the investigation of the heat resistance of a 0.07C–12Cr–Ni–Mo–V–Nb steel of the martensitic–ferritic class, a reduction was revealed in the long-term strength of its welded joints ...to below the level of the strength of the base metal. To establish the causes for the accelerated failure of the welded joints, an imitation of the thermal cycles was carried out that produce the structure of the heataffected zone using a dilatometer. In the samples with the structure that corresponds to that of the heataffected zone, a local zone of softening was revealed. The investigations of the metal structure using transmission electron microscopy have shown that the reduction in the creep rupture strength was caused by structural changes under the conditions of the thermal cycle of welding upon the staying of the steel in the temperature range between the
Ac
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Calorimetry of the CMD-3 detector Akhmetshin, R R; Anisenkov, A V; Aulchenko, V M ...
Journal of physics. Conference series,
11/2017, Volume:
928, Issue:
1
Journal Article
Peer reviewed
Open access
The CMD-3 detector has been collecting data since 2010 at the e+e− collider VEPP-2000 in the Budker Institute of Nuclear Physics. VEPP-2000 uses the novel round beam technique and provides high ...luminosity in a wide c.m.energy range from 0.32 to 2 GeV. The physics goal of the CMD-3 experiment is a study of the e+e− annihilation into hadrons. CMD-3 is a general-purpose detector, which provides high efficiency for both charged and neutral particles. The electromagnetic calorimeter consists of the barrel calorimeter based on liquid xenon and CsI crystals, and the endcap calorimeter based on BGO crystals. The main parameters of the calorimeters are presented.
The cross section of the process e + e − → π + π − has been measured in the center-of-mass energy range from 0.32 to 1.2 GeV with the CMD-3 detector at the electron-positron collider VEPP-2000. The ...measurement is based on an integrated luminosity of about 88 pb − 1 , of which 62 pb − 1 represent a complete dataset collected by CMD-3 at center-of-mass energies below 1 GeV. In the dominant region near the ρ resonance a systematic uncertainty of 0.7% was achieved. The implications of the presented results for the evaluation of the hadronic contribution to the anomalous magnetic moment of the muon are discussed. Published by the American Physical Society 2024
The peculiarities of photoresist etching in inductively coupled plasma in various modes, including the mode using to etch the GaN-based structures are investigated. The continuous in situ monitoring ...of the photoresist thickness, surface morphology, and substrate temperature was performed with the help of the optical reflectometry and low-coherent interferometry. It is shown that the etch rate of photoresist is not constant but decreases in the course of the process, which is in addition associated with the substrate heating. It is revealed that the pulsed etching mode makes it possible to exclude the development of the roughness observed in the continuous mode. The comparison of the new data with the etch rates of the photoresist with the characteristic rates of GaN etching performed under the same conditions made it possible to determine the process parameters and photoresist thickness necessary to perform the mentioned etching process in the optimal mode.
The cross section of the process e+ e−→ KS KL π0 has been studied with the CMD-3 detector at the VEPP-2000 electron-positron collider in the center-of-mass energy range from 1.1 to 2 GeV. Preliminary ...results on the total cross section of the process are presented.
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