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V. M. Aulchenko

Publications and source records attributed to V. M. Aulchenko.

At least 55 records · Page 3Linked to original sources
arXiv2010

Measurement of $ϕ$(1020) meson leptonic width with CMD-2 detector at VEPP-2M Collider

The $ϕ$(1020) meson leptonic width has been determined from the combined analysis of 4 major decay modes of the resonance ($ϕ\to K^+ K^-,K^0_LK^0_S,π^+π^-π^0,ηγ$) studied with the CMD-2 detector at the VEPP-2M $e^+e^-$ collider. The following value has been obtained: $Γ(ϕ\to e^+e^-) = 1.235\pm 0.006\pm 0.022$ keV. The $ϕ(1020)$ meson parameters in four main decay channels have been also recalculated: $B(ϕ\to K^+K^-) = 0.493\pm 0.003\pm 0.007$, $B(ϕ\to K_LK_S) = 0.336\pm 0.002\pm 0.006$, $B(ϕ\toπ^+π^-π^0) = 0.155\pm 0.002\pm 0.005$, $B(ϕ\toηγ) = 0.0138\pm 0.0002\pm 0.0002$.

hep-ex↗
arXiv2010

Measurement of J/psi to eta_c gamma at KEDR

We present a study of the inclusive photon spectra from 5.9 million J/psi decays collected with the KEDR detector at the VEPP-4M e+e- collider. We measure the branching fraction of radiative decay J/psi to eta_c gamma, eta_c width and mass. Our preliminary results are: M(eta_c) = 2979.4+-1.5+-1.9 MeV, G(eta_c) = 27.8+-5.1+-3.3 MeV, B(J/psi to eta_c gamma) = (2.34+-0.15+-0.40)%.

hep-ex↗
arXiv2010

Measurement of Γ_{ee}(J/ψ)*Br(J/ψ->e^+e^-) and Γ_{ee}(J/ψ)*Br(J/ψ->μ^+μ^-)

The products of the electron width of the J/ψmeson and the branching fraction of its decays to the lepton pairs were measured using data from the KEDR experiment at the VEPP-4M electron-positron collider. The results are Γ_{ee}(J/ψ)*Br(J/ψ->e^+e^-)=(0.3323\pm0.0064\pm0.0048) keV, Γ_{ee}(J/ψ)*Br(J/ψ->μ^+μ^-)=(0.3318\pm0.0052\pm0.0063) keV. Their combinations Γ_{ee}\times(Γ_{ee}+Γ_{μμ})/Γ=(0.6641\pm0.0082\pm0.0100) keV, Γ_{ee}/Γ_{μμ}=1.002\pm0.021\pm0.013 can be used to improve theaccuracy of the leptonic and full widths and test leptonic universality. Assuming eμuniversality and using the world average value of the lepton branching fraction, we also determine the leptonic Γ_{ll}=5.59\pm0.12 keV and total Γ=94.1\pm2.7 keV widths of the J/ψmeson.

hep-ex↗
arXiv2010

Recent results from the KEDR Detector

We report results of experiments performed with the KEDR detector at the VEPP-4M e+e- collider. They include precise measurement of the D0 and D+- meson masses, determination of the psi(3770) resonance parameters, and a search for narrow resonances in e+e- annihilation at center-of-mass energies between 1.85 and 3.1 GeV.

hep-ex↗
arXiv2008

Application of introduced nano-diamonds for the study of carbon condensation during detonation of high explosives

This paper describes the experimental studies of the formation of nano-diamonds during detonation of TNT/RDX 50/50 mixture with small-angle x-ray scattering (SAXS) method at a synchrotron radiation beam on VEPP-3 accelerator. A new experimental method with introduction of nano-diamonds into the explosive has been applied. Inclusion of the diamonds obtained after detonation into the TNT and RDX explosives allows modelling of the case of instant creation of nano-diamonds during detonation.

cond-mat.other↗
arXiv2008

Study of the process e+e-\to μ+μ- in the energy region \sqrt{s}=980, 1040 -- 1380 MeV

The cross section of the process e+e-\toμ+μ- was measured in the SND experiment at the VEPP-2M e+e- collider in the energy region \sqrt{s}=980, 1040 -- 1380 MeV. The event numbers of the process e+e-\toμ+μ- were normalized to the integrated luminosity measured using e+e-\to e+e- and e+e-\toγγprocesses. The ratio of the measured cross section to the theoretically predicted value is 1.006\pm 0.007 \pm 0.016 and 1.005 \pm 0.007 \pm 0.018 in the first and second case respectively. Using results of the measurements, the electromagnetic running coupling constant αin the energy region \sqrt{s}=1040 -- 1380 MeV was obtained <1/α> = 134.1\pm 0.5 \pm 1.2 and this is in agreement with theoretical expectation.

hep-ex↗
arXiv2008

Measurement of e+e- -> phi -> K+K- cross section with the CMD-2 detector at VEPP-2M Collider

The process e+ e- -> phi -> 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 phi(1020) meson parameters in the phi -> K+K- decay channel have been measured: sigma_0(phi-> K+K-) = 2016 +- 8 +- 44 nb, m(phi) = 1019.441 +- 0.008 +- 0.080 MeV/c2, Gamma(phi) = 4.24 +- 0.02 +- 0.03 MeV, B(e+e-)B(K+K-) = (14.27 +- 0.05 +- 0.31)*10(-5).

hep-ex↗
arXiv2008

Investigation of the $e^+e^- \to ωπ^0 \to π^0 π^0 γ$ reaction in the energy domain near the $ϕ$-meson

The $e^+e^- \to ωπ^0 \to π^0 π^0 γ$ process was investigated in the SND experiment at the VEPP-2M collider. A narrow energy interval near the $ϕ$-meson was scanned. The observed cross-section reveals, at the level of three standard deviation, the interference effect caused by $ϕ\to π^0π^0γ$ decay. The cross-section parameters, as well as the real and imaginary parts of the $ϕ$-meson related amplitude, were measured.

hep-ex↗
arXiv2008

Detector for imaging of explosions: present status and future prospects with higher energy X-rays

The detector for imaging of explosions (DIMEX) is in operation at the synchrotron radiation (SR) beam-line at VEPP-3 electron ring at Budker INP since 2002. DIMEX is based on one-coordinate gas ionization chamber filled with Xe-CO2(3:1) mixture at 7atm, and active Frisch-grid made of Gas Electron Multiplier (GEM). The detector has spatial resolution of ~0.2mm and dynamic range of ~100 that allows to realize the precision of signal measurement at a percent level. The frame rate can be tuned up to 8 MHz (125 ns per image) and up to 32 images can be stored in one shot. At present DIMEX is used with the X-ray beam from 2T wiggler that has ~20 keV average energy. Future possibility to install similar detector at the SR beam-line at VEPP-4 electron ring is discussed.

physics.ins-det↗
arXiv2007

Development of one-coordinate gaseous detector for wide angle diffraction studies

A one-coordinate gaseous detector of soft X-ray photons for wide-angle X-ray scattering (WAXS) studies is being developed. The detector operates in counting mode and is based on multi-stage Gas Electron Multiplier(GEM). Full size detector is assembled and has 67 degrees aperture with 350mm distance to the source, readout multi-strip structure with 2048 strips at 0.2mm pitch and is partially equipped with readout electronics in the central part. Main parameters of the detector have been measured with 8keV X-ray beam at VEPP-3 synchrotron ring. Spatial resolution of 470 um (FWHM) has been demonstrated that will allow to distinguish diffraction spots at 0.1 degrees.

physics.ins-det↗
arXiv2006

New precise determination of the τlepton mass at KEDR detector

The status of the experiment on the precise $τ$ lepton mass measurement running at the VEPP-4M collider with the KEDR detector is reported. The mass value is evaluated from the $τ^+τ^-$ cross section behaviour around the production threshold. The preliminary result based on 6.7 pb$^{-1}$ of data is $m_τ=1776.80^{+0.25}_{-0.23} \pm 0.15$ MeV. Using 0.8 pb$^{-1}$ of data collected at the $ψ'$ peak the preliminary result is also obtained: $Γ_{ee}B_{ττ}(ψ') = 7.2 \pm 2.1$ eV.

hep-ex↗
arXiv2006

Study of the $e^+e^-\toηγ$ process with SND detector at the VEPP-2M $e^+e^-$ collider

In experiment with the SND detector at VEPP-2M $e^+e^-$ collider the $e^+e^-\toηγ$ cross section was measured in the energy range $E$=0.60--1.38 GeV with the integrated luminosity of 27.8 pb$^{-1}$. The measured cross section is well described by the vector meson dominance model with contributions from the $ρ(770)$, $ω(783)$, $ϕ(1020)$, $ρ^{\prime}(1465)$ resonances and agrees with results of previous measurements. The decay probabilities $\BR(ϕ\toηγ)$, $\BR(ω\toηγ)$ and $\BR(ρ\toηγ)$ were measured with the accuracies better than or comparable to the world averages.

hep-ex↗
arXiv2003

New precision measurement of the $J/ψ$- and $ψ'$ -meson masses

A new high precision measurement of the $J/ψ$- and $ψ'$-meson masses has been performed at the VEPP-4M collider using the KEDR detector. The resonant depolarization method has been employed for the absolute calibration of the beam energy. The following mass values have been obtained: $M_{J/ψ} = 3096.917 \pm 0.010 \pm 0.007$ MeV, $M_{ψ'} = 3686.111 \pm 0.025 \pm 0.009$ MeV. The relative measurement accuracy has reached $4. 10^{-6}$ for $J/ψ$ and $7. 10^{-6}$ for $ψ'$, approximately 3 times better than in the previous precise experiments.

hep-ex↗
arXiv2002

Study of the process $e^+e^- \to π^+π^-π^0$ in the energy region $\sqrt[]{s}$ from 0.98 to 1.38 GeV.}

The cross section of the process $e^+e^-\to π^+π^-π^0$ was measured in the Spherical Neutral Detector experiment at the VEPP-2M collider in the energy region $\sqrt[]{s} = 980 ÷1380$ MeV. The measured cross section, together with the $e^+e^-\to π^+π^-π^0$ and $ωπ^+π^-$ cross sections obtained in other experiments, was analyzed in the framework of the generalized vector meson dominance model. It was found that the experimental data can be described by a sum of $ω$, $ϕ$ mesons and two $ω^\prime$ and $ω^{\prime\prime}$ resonances contributions, with masses $m_{ω^\prime}\sim 1490$,$m_{ω^{\prime\prime}}\sim 1790$ MeV and widths $Γ_{ω^\prime}\sim 1210$, $Γ_{ω^{\prime\prime}}\sim 560$ MeV. The analysis of the $π^+π^-$ invariant mass spectra in the energy region $\sqrt[]{s}$ from 1100 to 1380 MeV has shown that for their descriptionone should take into account the $e^+e^-\toωπ^0\toπ^+π^-π^0$ mechanism also. The phase between the amplitudes corresponding to the $e^+e^-\toωπ$ and $e^+e^-\toρπ$ intermediate states was measured for the first time. The value of the phase is close to zero and depends on energy.

hep-ex↗
arXiv2001

Review of experimental results from SND detector

The review of experimental results obtained with SND detector at VEPP-2M $e^+e^-$ collider in the energy region $\sqrt[]{s}=0.36$ -- 1.38 GeV is given. The presented results include the following items: studies of the light vector mesons radiative decays, OZI-rule and G-parity suppressed $ϕ$-meson rare decays, $ϕ$-meson parameters measurements, studies of $e^+e^-\toπ^+π^-π^0$ process dynamics, $η$ and $K_S$ mesons rare decays, $η$ and $ϕ$ mesons conversion decays, and study of the $e^+e^-$ annihilation into hadrons.

hep-ex↗