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E. A. Perevedentsev

Publications and source records attributed to E. A. Perevedentsev.

At least 19 recordsLinked to original sources
arXiv2026

Neutral kaon mass measurement with the CMD-3 derector at VEPP-2000

Using more than 600 thousand $K_{S}^{0}\toπ^{+}π^{-}$ decays from the $e^{+}e^{-}\toϕ(1020)\to K_{S}^{0}K_{L}^{0}$ reaction, the neutral kaon mass has been measured with the CMD-3 detector at the VEPP-2000 collider. Using the beam energies control by the back-scattering laser light photons, and a calibration to the world average $ϕ$-meson mass, the neutral kaon mass is determind to be m($K^0$) = 497.587 $\pm$ 0.004(stat.) $\pm$ 0.008(syst.) $\pm$ 0.009(calibr.) \mevcc, where the first uncertainty is statistical, the second is systematic, and the third is the uncertainty from the energy calibration.

hep-ex↗
arXiv2026

Study of the proccess $e^+e^-\to π^+π^-π^0π^0η$ in the c.m. energy range 1.6--2.0 GeV with the CMD-3 detector

The cross section of the process $e^+e^- \to π^+π^-π^0π^0η$ has been measured using a data sample with the integrated luminosity of 372 pb$^{-1}$ collected with the CMD-3 detector at the VEPP-2000 $e^+e^-$ collider. 6300$\pm$145 signal events have been selected in the center-of-mass energy range 1.6--2.0 GeV. The total systematic uncertainty of the cross section is about 10\%. The production dynamics is dominated by the $ω(782)π^0η$ final state with a possible small contribution of the $a_0(980)$ resonance in the $π^0η$ combination. We also observe a presence of the $ρ(770)^{\pm}$ resonance signal in the $π^{\pm}π^0$ invariant mass distribution.

hep-ex↗
arXiv2026

Measurement of the $e^+e^-\toπ^+π^-π^0$ cross section in the energy region from 0.56 to 1.1 GeV with the SND detector

The precise measurement of the $e^+e^-\toπ^+π^-π^0$ cross section is performed in the center-of-mass energy range $E = 560$--1100 MeV using a data sample of 66 pb$^{-1}$ collected in the experiment with the SND detector at the VEPP-2000 $e^+e^-$ collider. The systematic uncertainty of the cross section measurement is 0.9\% at the maximum of the $ω$ resonance and 1.2\% at the maximum of the $ϕ$ resonance. The leading-order hadronic contribution to the muon magnetic anomaly calculated using the $e^+e^-\toπ^+π^-π^0$ cross section measured by SND from 0.62 to 1.975 GeV is $(45.95\pm0.06\pm 0.47)\times 10^{-10}$. From the fit to the cross section data with the vector meson dominance model, the parameters of the $ω$, $ρ$, and $ϕ$ resonances are obtained. The obtained values of ${\cal B}(ω\to e^+e^-) {\cal B}(ω\to 3π)$, mass and width of the $ω$ meson, and ${\cal B}(ρ\to 3π)$ have accuracy better than the current world average values.

hep-ex↗
arXiv2024

Measurement of the $e^+e^-\toπ^+π^-$ cross section from threshold to 1.2 GeV with the CMD-3 detector

The cross section of the process $e^+e^-\toπ^+π^-$ 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.

hep-ex↗
arXiv2024

Measurement of the pion form factor with CMD-3 detector and its implication to the hadronic contribution to muon (g-2)

The cross section of the process $e^+e^-\toπ^+π^-$ 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.

hep-ex↗
arXiv2023

Study of the process $e^+e^- \to ωπ^0 \to π^+π^-π^0π^0$ in the energy range $1.05-2.00$ GeV with SND

The process $e^+e^- \to ωπ^0 \to π^+π^-π^0π^0$ is studied in the center-of-mass energy region $1.05-2.00$ GeV using data with an integral luminosity of about 35 pb$^{-1}$ collected with the SND detector at the VEPP-2000 $e^+e^-$ collider. In the energy range under study, the value of the measured Born cross section varies from 0.7 to 18 nb. The statistical uncertainty of the cross section is $2-23$%, while the systematic uncertainty is in the range of $3.0-14.2$%. The results are consistent with previous measurements but have better accuracy.

hep-ex↗
arXiv2022

Experimental study of the $e^+e^-\to n\bar n$ process at the VEPP-2000 $e^+e^-$ collider with the SND detector

The process $e^+e^-\to n\bar n$ is studied in the experiment at the VEPP-2000 $e^+e^-$ collider with the SND detector. The technique of the time measurements in the multichannel NaI(Tl) electromagnetic calorimeter is used to select nnbar events. The value of the measured cross section in the center-of-mass energy range from 1.894 to 2 GeV varies from 0.5 to 0.35 nb. The effective neutron timelike form factor is derived from the measured cross section and compared with the proton form factor. The ratio of the neutron electric and magnetic form factors is obtained from the analysis of the antineutron polar angle distribution and found to be consistent with unity.

hep-ex↗
arXiv2020

Measurement of the $e^+e^- \to K^+ K^- π^0$ cross section with the SND detector

The process $e^+e^-\to K^+K^-π^0$ is studied with the SND detector at the VEPP-2000 $e^+e^-$ collider. Basing on data with an integrated luminosity of 26.4~pb$^{-1}$ we measure the $e^+e^-\to K^+K^-π^0$ cross section in the center-of-mass energy range from 1.28 up to 2 GeV. The measured mass spectrum of the $Kπ$ system indicates that the dominant mechanism of this reaction is the transition through the $K^{\ast}(892)K$ intermediate state. The cross section for the $ϕπ^0$ intermediate state is measured separately. The SND results are consistent with previous measurements in the BABAR experiment and have comparable accuracy. We study the effect of the interference between the $ϕπ^0$ and $K^\ast K$ amplitudes. It is found that the interference gives sizable contribution to the measured $e^+e^- \to ϕπ^0\to K^+K^-π^0$ cross section below 1.7 GeV.

hep-ex↗
arXiv2020

Measurement of the $e^+e^- \toπ^+π^- $ process cross section with the SND detector at the VEPP-2000 collider in the energy region $0.525<\sqrt{s}<0.883$ GeV

The cross section of the process $e^+ e^-\toπ^+π^-$ has been measured in the Spherical Neutral Detector (SND) experiment at the VEPP-2000 $e^+e^-$ collider VEPP-2000 in the energy region $525 <\sqrt[]{s} <883$ MeV. The measurement is based on data with an integrated luminosity of about 4.6 pb$^{-1}$. The systematic uncertainty of the cross section determination is 0.8 % at $\sqrt{s}>0.600$ GeV. The $ρ$ meson parameters are obtained as $m_ρ= 775.3\pm 0.5\pm 0.6$ MeV, $Γ_ρ= 145.6\pm 0.6\pm 0.8$ MeV, $B_{ρ\to e^+ e^-}\times B_{ρ\toπ^+π^-} = (4.89\pm 0.02\pm 0.04)\times 10^{-5}$, and the parameters of the $e^+ e^-\toω\toπ^+π^-$ process, suppressed by $G$-parity, as $B_{ω\to e^+ e^-}\times B_{ω\toπ^+π^-}= (1.32\pm 0.06\pm 0.02)\times 10^{-6} $ and $ϕ_{ρω} = 110.7\pm 1.5\pm1.0$ degrees.

hep-ex↗
arXiv2019

Search for direct production of the $f_1(1285)$ resonance in $e^+e^-$ collisions

A search for direct production of the $f_1(1285)$ resonance in $e^+e^-$ annihilation is performed with the SND detector at the VEPP-2000 $e^+e^-$ collider. The analysis is based on data with an integrated luminosity of 15.1 pb$^{-1}$ accumulated in the center-of-mass energy range 1.2--1.4 GeV. Two $e^+e^-\to f_1(1285)$ candidate events are found at the peak of the resonance and zero events beyond the resonance. The significance of the $e^+e^-\to f_1(1285)$ signal is $2.5σ$. The cross section at the maximum of the resonance is found to be $σ(e^+e^-\to f_1)=45^{+33}_{-24}$ pb. The corresponding branching fraction $B(f_1(1285)\to e^+e^-)=(5.1^{+3.7}_{-2.7})\times 10^{-9}$. We consider this result as a first indication of the process $e^+e^-\to f_1(1285)$. The measured branching fraction is consistent with the theoretical prediction.

hep-ex↗
arXiv2019

Study of the process $e^+e^-{\to}K^+K^-η$ with the CMD-3 detector at the VEPP-2000 collider

The process $e^+e^-{\to}K^+K^-η$ 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 $e^+e^-{\to}ϕ(1020)η$ has been measured with a systematic uncertainty of 5.1$\%$ on the base of 3009 $\pm$ 67 selected events. The obtained cross section has been used to calculate the contribution to the anomalous magnetic moment of the muon: $a_μ^{ϕη}(E<1.8\, {\rm GeV})=(0.321 \pm 0.015_{\rm stat} \pm 0.016_{\rm syst}) \times 10^{-10}$, $a_μ^{ϕη}(E<2.0\, {\rm GeV})=(0.440 \pm 0.015_{\rm stat} \pm 0.022_{\rm syst}) \times 10^{-10}$. From the cross section approximation the $ϕ(1680)$ meson parameters have been determined with better statistical precision, than in previous studies.

hep-ex↗
arXiv2019

Measurement of the $e^+e^- \to π^+π^-π^0η$ cross section below $\sqrt{s}=2$ GeV

The process $e^+e^- \to π^+π^-π^0η$ is studied in the center-of-mass energy region below 2 GeV with the SND detector at the VEPP-2000 $e^+e^-$ collider. The four intermediate states contribute to this process: $ωη$, $ϕη$, $a_0(980)ρ$, and a structureless $π^+π^-π^0η$ state. We measure the total $e^+e^- \to π^+π^-π^0η$ cross section and the cross sections for its components: $ωη$, $ϕη$, and a sum of $a_0(980)ρ$ and the structureless state. Our results are in agreement with previous measurements and have comparable or better accuracies.

hep-ex↗
arXiv2017

Measurement of the $e^+e^- \to ηπ^+π^-$ cross section with the SND detector at the VEPP-2000 collider

The $e^+e^- \to ηπ^+π^-$ cross section is measured at the SND detector in the $η$ decay mode $η\to 3π^0$. The analysis is based on the data sample with an integrated luminosity of 32.7 pb$^{-1}$ collected at the VEPP-2000 $e^+e^-$ collider in the center-of-mass energy range $\sqrt{s}=1.075-2.000$ GeV. The data obtained in the $η\to 3π^0$ decay mode are found to be in agreement with the previous SND measurements in the $η\to γγ$ mode. Therefore the measurements in the two modes are combined.

hep-ex↗
arXiv2017

Study of the process $e^+e^- \to K^+K^-$ in the center-of-mass energy range 1010--1060~MeV with the CMD-3 detector

The process $e^+e^- \to K^+K^-$ has been studied using $1.7 \times 10^6$ events from a data sample corresponding to an integrated luminosity of 5.7 pb$^{-1}$ collected with the CMD-3 detector in the center-of-mass energy range 1010--1060 MeV. The cross section measured with an about 2\% systematic uncertainty and it is used to calculate the contribution to the anomalous magnetic moment of the muon $a_μ^{K^+K^-} = (19.33 \pm 0.40) \times 10^{-10}$, and to obtain the $ϕ(1020)$ meson parameters. We consider the relationship between the $e^+e^- \to K^+K^-$ and $e^+e^- \to K^0_SK^0_L$ cross sections and compare it to the theoretical expectations.

hep-ex↗
arXiv2017

Correction of magnetic optics and beam trajectory using LOCO based algorithm with expanded experimental data sets

Precise beam based measurement and correction of magnetic optics is essential for the successful operation of accelerators. The LOCO algorithm is a proven and reliable tool, which in some situations can be improved by using a broader class of experimental data. The standard data sets for LOCO include the closed orbit responses to dipole corrector variation, dispersion, and betatron tunes. This paper discusses the benefits from augmenting the data with four additional classes of experimental data: the beam shape measured with beam profile monitors; responses of closed orbit bumps to focusing field variations; betatron tune responses to focusing field variations; BPM-to-BPM betatron phase advances and beta functions in BPMs from turn-by-turn coordinates of kicked beam. All of the described features were implemented in the Sixdsimulation software that was used to correct the optics of the VEPP-2000 collider, the VEPP-5 injector booster ring, and the FAST linac.

physics.acc-ph↗
arXiv2016

Study of the Process $e^+e^-\to π^+π^-π^+π^-$ IN THE C.M. Energy Range 920--1060 MeV with the CMD-3 Detector

A cross section of the process $e^+e^- \to \pipi\pipi$ has been measured using 6798$\pm$93 signal events from a data sample corresponding to an integrated luminosity of 9.8 pb$^{-1}$ collected with the CMD-3 detector in the center-of-mass energy range 920--1060 MeV. The measured cross section exhibits an interference pattern of the $ϕ(1020)\to\pipi\pipi$ decay with a non-resonant process $e^+e^- \to \pipi\pipi$, from which we obtain the branching fraction of the doubly suppressed decays (by G-parity and OZI rule): $\BR(ϕ\to\pipi\pipi) = (6.5\pm2.7\pm1.6)\times 10^{-6}$.

hep-ex↗
arXiv2016

Measurement of the $\mathbf{e^+e^-\to K^+K^-}$ cross section in the energy range $\mathbf{\sqrt{s}=1.05-2.0}$ GeV

The $e^+e^-\to K^+K^-$ cross section is measured in the center-of-mass energy range $1.05-2.00$ GeV at the SND detector. The measurement is based on data with an integrated luminosity of 35 pb$^{-1}$ collected at the VEPP-2000 $e^+e^-$-collider. The obtained results are consistent with the previous most accurate data obtained in the BABAR experiment and have a comparable accuracy.

hep-ex↗