A
bstract
The cross section of the process
e
+
e
−
→ ηπ
+
π
−
is measured using the data collected with the CMD-3 detector at the VEPP-2000 collider in the center-of-mass energy range from 1
.
1 to 2
....
0 GeV. The decay mode
η → γγ
is used for
η
meson reconstruction in the data sample corresponding to an integrated luminosity of 78
.
3 pb
−
1
. The energy dependence of the
e
+
e
−
→ ηπ
+
π
−
cross section is fitted within the framework of vector meson dominance in order to extract the Γ(
ρ
(1450)
→ e
+
e
−
)
B
(
ρ
(1450)
→ ηπ
+
π
−
) and the Γ(
ρ
(1700)
→ e
+
e
−
)
B
(
ρ
(1700)
→ ηπ
+
π
−
) products. Based on conservation of vector current, the analyzed data are used to test the relationship between the
e
+
e
−
→ ηπ
+
π
−
cross section and the spectral function in
τ
−
→ ηπ
−
π
0
ντ
decay. The
e
+
e
−
→ ηπ
+
π
−
cross section obtained with the CMD-3 detector is in good agreement with the previous measurements.
Abstract
In 2018, a test run with muons in the North Area at CERN was
performed, running parasitically downstream of the COMPASS
spectrometer. The aim of the test was to investigate the elastic
...interactions of muons on atomic electrons, in an experimental
configuration similar to the one proposed by the project MUonE,
which plans to perform a very precise measurement of the
differential cross-section of the elastic interactions.
COMPASS was taking data with a 190 GeV π beam, stopped in a
tungsten beam dump: the muons from these π decays passed through
a setup including a graphite target followed by 10 planes of Si
tracker and a BGO crystal electromagnetic calorimeter placed at the
end of the tracker. The elastic scattering events were selected and
analysed, and compared to expectations from MonteCarlo
simulation. The agreement found was satisfactory and demonstrated
that measuring the angles of the outgoing particles, a clean sample
of elastic interaction could be identified.
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
Full text
Available for:
CMK, CTK, FMFMET, IJS, NUK, PNG, UL, UM
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
Full text
Available for:
CMK, CTK, FMFMET, IJS, NUK, PNG, UM
The article assesses the possibility of using ash and slag mixture for the construction of a road bed. To this end, the traditional and modern methods of calculation of road surfaces are analyzed, ...which allow establishing the parameters of strength and deformability that require experimental determination. Experimental determination of strength and deformability parameters is performed by laboratory tests. For the implementation of tests the authors make samples of ash and slag mixture of different density. During the experiments, the metal stamp is pressed into the model and the experimental dependences of the sediment on the pressure are determined. This makes it possible to calculate the California Bearing Ratio, the deformation modulus, and to establish the pressures at which the mixture of ash and slag operates under compaction or shear conditions. Mathematical models are developed to calculate the parameters of strength and deformability from the value of pressure.
The updated results of the precise measurements of the processes e+e−→ρ→π+π−, e+e−→ω→π+π−π0 and e+e−→φ→K0LK0S performed by the CMD-2 Collaboration are presented. The update appeared necessary due to ...an overestimate of the integrated luminosity in previous analyses.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
The influence of compositions based on 1H,1H,9H-trihydroperfluorononan-1-ol, montmorillonite, and polytetrafluoroethylene Fluralite on the structure and wear resistance of the polyurethane elastomer ...modified by them is considered. The introduction of polyelement modifiers leads to the reorganization of the amorphous structure of the polymer matrix and changes in the properties of the surface. There is an increase in the intensity of the amorphous halo and a decrease in its radial half-width. According to the methods of X-ray photoelectron spectroscopy and X-ray microanalysis, the surface (up to 3 nm) and deep layers (up to 5 μm) of the modified polyurethane elastomer are enriched with fluorine, which together leads to the formation of a hydrophobic boundary lubricant layer and provides increased wear resistance. The developed polyurethane composites may be of interest as monolithic sports, roofing, and waterproofing coatings.
Full text
Available for:
EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
In the article the analysis of methods of calculating non-rigid road pavements according to the criterion of elastic deflection. The possibility of using different solutions (Burmister, Korsunsky, ...Ivanov, etc.) to calculate the deflection of layers of monolithic and granular materials is evaluated. Based on this analysis, the formulas for calculating the equivalent modulus of elasticity of a two-layer system, the upper layer of which is made of monolithic or granular material, are recommended. The authors made the modification of formulas for calculating the deflection of asphalt concrete layers and the equivalent modulus of elasticity on their surface. The modification was made by introducing into the calculated dependences a scalar quantity, called damage. To calculate the damage, the principle of equivalence of deformations is recommended, in which the damage is determined using the relations of elastic modules of the damaged and solid body. To calculate the elastic modulus of the damaged body, a functional dependence on the number of loads was obtained.
Overview of the CMD-3 recent results Ryzhenenkov, A E; Akhmetshin, R R; Amirkhanov, A N ...
Journal of physics. Conference series,
04/2020, Volume:
1526, Issue:
1
Journal Article
Peer reviewed
Open access
The CMD-3 detector started data taking at the electron-positron collider VEPP-2000 in December 2010 with a goal to collect about 1 fb−1. The collected data sample corresponds to an integrated ...luminosity of 200 pb−1 in the center-of-mass energy range from 0.32 up to 2 GeV. This paper reports recent results on the hadronic cross sections measurements with the CMD-3 detector.
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