Phys. Rev. D 94, 112006 (2016) 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.
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 \(2.5\sigma\). The cross section at the maximum of the resonance is found to be \(\sigma(e^+e^-\to f_1)=45^{+33}_{-24}\) 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.
In the study of the reaction $e^+e^-\to K_{S}K_{L}$ at the VEPP-2M $e^+e^-$
collider with the SND detector the nuclear interaction length of $K_{L}$ meson
in NaI(Tl) has been measured. Its value is ...found to be 30--50 cm in the $K_{L}$
momentum range 0.11--0.48 GeV/$c$. The results are compared with the values
used in the simulation programs GEANT4 and UNIMOD.
Spherical Neutral Detector (SND) is a general purpose non-magnetic detector for experiments at VEPP-2000 e+e− collider in Novosibirsk in the energy range 2E=0.4–2.0GeV. Charged particle track ...coordinates are measured using drift and proportional chambers placed in a common gas volume. Particle identification is performed using energy deposition in the drift chamber at low particle momenta p⩽300MeV and aerogel threshold counters at high particle momenta p⩾300MeV. Photon energies are measured using 3-layer spherical electromagnetic calorimeter. Muons penetrating the detector and cosmic background muons are detected by the muon system based on proportional tubes and plastic scintillator counters. At present the detector is operating at VEPP-2000.
The process \(e^+e^- \to \pi^+\pi^-\pi^0\eta\) 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: \(\omega\eta\), \(\phi\eta\), \(a_0(980)\rho\), and a structureless \(\pi^+\pi^-\pi^0\eta\) state. We measure the total \(e^+e^- \to \pi^+\pi^-\pi^0\eta\) cross section and the cross sections for its components: \(\omega\eta\), \(\phi\eta\), and a sum of \(a_0(980)\rho\) and the structureless state. Our results are in agreement with previous measurements and have comparable or better accuracies.
The cross section of the process e+e-\to\mu+\mu- 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-\to\mu+\mu- were normalized to the integrated luminosity measured using e+e-\to e+e- and e+e-\to\gamma\gamma processes. 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 \alpha in the energy region \sqrt{s}=1040 -- 1380 MeV was obtained <1/\alpha> = 134.1\pm 0.5 \pm 1.2 and this is in agreement with theoretical expectation.
The number of \(\psp\) events accumulated by the BESIII experiment from March 3 through April 14, 2009, is determined by counting inclusive hadronic events. The result is \(106.41\times(1.00\pm ...0.81%)\times 10^{6} \). The error is systematic only; the statistical error is negligible.
