arXiv subjects

E. A. Bekhtenev

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

6 recordsLinked to original sources

arXiv2025

Low-impedance stripline kicker for the transverse instability suppression system of the synchrotron radiation facility "SKIF" light source

Construction of the new fourth generation synchrotron radiation facility (SRF) "SKIF" near Novosibirsk is nearing completion. "SKIF" uniqueness is ultra-low 75 pm natural emittance at 400 mA beam current and 3 GeV beam energy. Collective effects (beam interaction with the vacuum chamber) are the main obstacles of achieving such emittance and beam current. To suppress these effects the storage ring will be equipped with a bunch-by-bunch feedback system. Important components of the feedback system are a stripline (fast) kicker and a beam position monitor. The paper describes design of the low-impedance stripline kicker for SRF "SKIF" storage ring, optimized for the manufacturing and for the uniformity of the imparted transverse kick. The kicker qualities such as S-parameters, imparted transverse momentum, transfer and beam impedances are presented. The chosen length of the stripline kicker allows its use as a beam position monitor.

physics.acc-ph↗

arXiv2025

The branching fraction measurements of $J/ψ$ decay into $ρη$ and $ϕη$ final states

We present measurements of the branching fractions for the $J/ψ$ meson decays into the $ρη$ and $ϕη$ final states, based on data collected with the KEDR detector at the VEPP-4M collider. The data set consisted of 4.93 million $J/ψ$ events. The resulting branching fractions are: - $\mathcal{B}(J/ψ\to ρη) = (2.04 \pm 0.58 \pm 0.39)\times 10^{-4}$, - $\mathcal{B}(J/ψ\to ϕη) = (7.82 \pm 1.17 \pm 0.58) \times 10^{-4}$, where the first uncertainty is statistical and the second one is systematic. In the study of the $ρη$ decay, the dynamics of $J/ψ\toπ^+π^-η$ is analyzed. The hints from contributions of $ρ(1450)η$ and $a^{\pm}_2π^{\mp}$ intermediate states are observed. Additional measured branching fractions in the model that includes $ρ(1450)η$ and $a^{\pm}_2π^{\mp}$ are: - $\mathcal{B}(J/ψ\to π^+π^-η) = (4.73 \pm 0.49 \pm 1.17)\times10^{-4}$, - $\mathcal{B}(J/ψ\to (a_2^+π^- + a_2^- π^+)) = (1.05\pm 0.37 \pm 0.34)\times 10^{-3}$, - $\mathcal{B}(J/ψ\to ρ(1450)η\to π^+π^-η) < 1.51 \times 10^{-4}$, at a confidence level of 90\%. All results are consistent with previous studies.

hep-ex↗

arXiv2025

New measurement of D0 and D+ meson masses with the KEDR detector

Using the 4.9 pb$^{-1}$ statistics collected at the peak of the $ψ(3770)$ resonance with the KEDR detector at the VEPP-4M electron-positron collider, we measured the masses of the neutral and charged D mesons: $M_{D^0} = 1865.100 \pm 0.210 (stat) \pm 0.046 (syst) MeV,$ and $M_{D^+} = 1869.560 \pm 0.288 (stat) \pm 0.109 (syst) MeV$.

hep-ex↗

arXiv2023

Measurement of the branching fraction of $J/ψ\rightarrowρπ$ at KEDR

We present the study of the decay $J/ψ\rightarrow ρπ$. The results are based on of 5.2~million $J/ψ$ events collected by the KEDR detector at the VEPP-4M collider. The branching fractions are measured to be $\B(J/ψ\rightarrow ρπ) = \big(2.072\pm 0.017 \pm 0.062 \big)\cdot 10^{-2}$ and $\B(J/ψ\rightarrow π^+π^-π^0) = \big(1.878 \pm 0.013 \pm 0.051 \big)\cdot 10^{-2}$, where the first uncertainties are statistical and the second systematic. Our results are more precise than the previous relative measurements.

hep-ex↗

arXiv2018

Precise measurement of $R_{\text{uds}}$ and $R$ between 1.84 and 3.72 GeV at the KEDR detector

The present work continues a series of the KEDR measurements of the $R$ value that started in 2010 at the VEPP-4M $e^+e^-$ collider. By combining new data with our previous results in this energy range we measured the values of $R_{\text{uds}}$ and $R$ at nine center-of-mass energies between 3.08 and 3.72 GeV. The total accuracy is about or better than $2.6\%$ at most of energy points with a systematic uncertainty of about $1.9\%$. Together with the previous precise $R$ measurement at KEDR in the energy range 1.84-3.05 GeV, it constitutes the most detailed high-precision $R$ measurement near the charmonium production threshold.

hep-ex↗

arXiv2018

Measurement of $Γ_{ee}\times\mathcal{B}_{μμ}$ for $ψ(2S)$ meson

The product of the electronic width of the $ψ(2S)$ meson and the branching fraction of its decay to the muon pair was measured in the $e^{+}e^{-} \to ψ(2S) \to μ^{+}μ^{-}$ process using nine data sets corresponding to an integrated luminosity of about 6.5 pb$^{-1}$ collected with the KEDR detector at the VEPP-4M electron-positron collider: \[ Γ_{ee}\times\mathcal{B}_{μμ} = 19.3 \pm 0.3 \pm 0.5 ~\text{eV}. \] Adding the previous KEDR results on hadronic and leptonic channels, the values of the $ψ(2S)$ electronic width were obtained under two assumptions: either with the assumption of lepton universality \[ Γ_{ee} = 2.279 \pm 0.015 \pm 0.042 ~\text{keV} \] or without it, summing up hadronic and three independent leptonic channels: \[ Γ_{ee} = 2.282 \pm 0.015 \pm 0.042 ~\text{keV}. \]

hep-ex↗