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.
The product of the electronic width of the $\psi(2S)$ meson and the branching
fraction of its decay to the muon pair was measured in the $e^{+}e^{-} \to
\psi(2S) \to \mu^{+}\mu^{-}$ 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: \
\Gamma_{ee}\times\mathcal{B}_{\mu\mu} = 19.3 \pm 0.3 \pm 0.5 ~\text{eV}. \
Adding the previous KEDR results on hadronic and leptonic channels, the values
of the $\psi(2S)$ electronic width were obtained under two assumptions: either
with the assumption of lepton universality \ \Gamma_{ee} = 2.279 \pm 0.015 \pm
0.042 ~\text{keV} \ or without it, summing up hadronic and three independent
leptonic channels: \ \Gamma_{ee} = 2.282 \pm 0.015 \pm 0.042 ~\text{keV}. \
The product of the electronic width of the $J/\psi$ meson and the branching
fractions of its decay to hadrons and electrons has been measured using the
KEDR detector at the VEPP-4M $e^+e^-$ collider. ...The obtained values are:
$\Gamma_{ee}(J/\psi) = 5.550 \pm 0.056 \pm 0.089 \, \text{keV}, $
$\Gamma_{ee}(J/\psi) \cdot \mathcal{B}_\text{hadrons}(J/\psi) = 4.884 \pm 0.048
\pm 0.078 \, \text{keV}, $ $\Gamma_{ee}(J/\psi) \cdot \mathcal{B}_{ee}(J/\psi)
= 0.3331 \pm 0.0066 \pm 0.0040 \, \text{keV}.$ The uncertainties shown are
statistical and systematic, respectively. Using the result presented and the
world-average value of the electronic branching fraction, one obtains the total
width of the $J/\psi$ meson: $\Gamma = 92.94 \pm 1.83 \, \text{keV}.$ These
results are consistent with the previous experiments.
Using the KEDR detector at the VEPP-4M $e^+e^-$ collider, we have determined
the values of $R$ at thirteen points of the center-of-mass energy between 1.84
and 3.05 GeV. The achieved accuracy is ...about or better than $3.9\%$ at most of
the energy points with a systematic uncertainty less than $2.4\%$.
A technology for developing Internet applications involving computer graphics is presented. Such applications enable Internet users create physically accurate models of global scene illumination and ...produce high-quality images; it also allows scene editing. Based on this technology, software for creating active presentations or services accessed via the Internet was developed. Architectural, technological, and software solutions that ensure effective modeling of illumination, produce realistic images, and ensure a reasonable response time when working with Internet applications are considered.
Phys. Lett. B 753 (2016) 533-541 Using the KEDR detector at the VEPP-4M $e^+e^-$ collider, we have measured
the values of $R_{\text{uds}}$ and $R$ at seven points of the center-of-mass
energy between ...3.12 and 3.72 GeV. The total achieved accuracy is about or
better than $3.3\%$ at most of energy points with a systematic uncertainty of
about $2.1\%$. At the moment it is the most accurate measurement of $R(s)$ in
this energy range.
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.
Phys. Lett. B 738 (2014), 391-396 Using the inclusive photon spectrum based on a data sample collected at the
$J/\psi$ peak with the KEDR detector at the VEPP-4M $e^+e^-$ collider, we
measured the ...rate of the radiative decay $J/\psi\to\gamma\eta_{\rm c}$ as well
as $\eta_{\rm c}$ mass and width. Taking into account an asymmetric photon
lineshape we obtained $\Gamma^0_{\gamma\eta_{\rm c}}=2.98\pm0.18
\phantom{|}^{+0.15}_{-0.33}$ keV, $M_{\eta_{\rm c}} = 2983.5 \pm 1.4
\phantom{|}^{+1.6}_{-3.6}$ MeV/$c^2$, $\Gamma_{\eta_{\rm c}} = 27.2 \pm 3.1
\phantom{|}^{+5.4}_{-2.6}$ MeV.
The product of the electronic width of the \(\psi(2S)\) meson and the branching fraction of its decay to the muon pair was measured in the \(e^{+}e^{-} \to \psi(2S) \to \mu^{+}\mu^{-}\) 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: \ \Gamma_{ee}\times\mathcal{B}_{\mu\mu} = 19.3 \pm 0.3 \pm 0.5 ~\text{eV}. \ Adding the previous KEDR results on hadronic and leptonic channels, the values of the \(\psi(2S)\) electronic width were obtained under two assumptions: either with the assumption of lepton universality \ \Gamma_{ee} = 2.279 \pm 0.015 \pm 0.042 ~\text{keV} \ or without it, summing up hadronic and three independent leptonic channels: \ \Gamma_{ee} = 2.282 \pm 0.015 \pm 0.042 ~\text{keV}. \
The product of the electronic width of the \(J/\psi\) meson and the branching fractions of its decay to hadrons and electrons has been measured using the KEDR detector at the VEPP-4M \(e^+e^-\) ...collider. The obtained values are: \(\Gamma_{ee}(J/\psi) = 5.550 \pm 0.056 \pm 0.089 \, \text{keV}, \) \(\Gamma_{ee}(J/\psi) \cdot \mathcal{B}_\text{hadrons}(J/\psi) = 4.884 \pm 0.048 \pm 0.078 \, \text{keV}, \) \(\Gamma_{ee}(J/\psi) \cdot \mathcal{B}_{ee}(J/\psi) = 0.3331 \pm 0.0066 \pm 0.0040 \, \text{keV}.\) The uncertainties shown are statistical and systematic, respectively. Using the result presented and the world-average value of the electronic branching fraction, one obtains the total width of the \(J/\psi\) meson: \(\Gamma = 92.94 \pm 1.83 \, \text{keV}.\) These results are consistent with the previous experiments.
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