-
M. N. Achasov, K. I. Beloborodov,
A. V. Berdyugin,
A. G. Bogdanchikov,
D. A. Bukin,
A. V. Vasil’ev,
V. B. Golubev,
T. V. Dimova,
V. P. Druzhinin,
I. A. Koop,
A. A. Korol’,
S. V. Koshuba,
E. V. Pakhtusova,
S. I. Serednyakov,
Z. K. Silagadze,
A. N. Skrinsky,
Yu. M. Shatunov
[show abstract]
[hide abstract]
ABSTRACT: We have searched for the process e+e- → K+K-π0 at energies up to 1.38 GeVin an experiment with the spherical neutral detector at the VEPP-2M e+e- collider. The upper limits of the cross sections for the processes σ(e+e →; φπ: → K+K-π0) < 0.023 nb and σ(e+e- → KK*(892) → K+K-π0) < 0.059 nb have been established at a 95% confidence level.
Journal of Experimental and Theoretical Physics 04/2012; 110(1):26-33. · 1.03 Impact Factor
-
M. N. Achasov, K. I. Beloborodov,
A. V. Berdyugin,
A. G. Bogdanchikov,
D. A. Bukin,
A. V. Vasil’ev,
V. B. Golubev,
T. V. Dimova,
V. P. Druzhinin,
I. A. Koop,
A. A. Korol’,
S. V. Koshuba,
E. V. Pakhtusova,
S. I. Serednyakov,
Z. K. Silagadze,
A. N. Skrinsky,
Yu. M. Shatunov,
D. A. Shtol’
[show abstract]
[hide abstract]
ABSTRACT: The e
+
e
− → ηπ+π− cross section in the η → 2γ channel has been measured in the $
\sqrt s
$
\sqrt s
= 1.04- to 1.38-GeV energy range. The data with a total integrated luminosity of 9.05 pb−1 were collected on a spherical neutral detector at the VEPP-2M collider. The results are consistent with the BaBar and CMD2
data and have a higher statistical accuracy.
JETP Letters 04/2012; 92(2):80-84. · 1.35 Impact Factor
-
M. N. Achasov, K. I. Beloborodov,
A. V. Berdyugin,
A. A. Botov,
A. V. Vasil’ev,
V. B. Golubev,
T. V. Dimova,
V. P. Druzhinin,
D. P. Kovrizhin,
I. A. Koop,
A. A. Korol’,
S. V. Koshuba,
A. E. Obrazovsky,
E. V. Pakhtusova,
S. I. Serednyakov,
Z. K. Silagadze,
A. G. Kharlamov,
Yu. M. Shatunov,
D. A. Shtol’
[show abstract]
[hide abstract]
ABSTRACT: The cross section for the process e
+
e
− → π+π−π0π0 has been measured in an experiment with a spherical neutral detector, with the cross section at energies √s < 920 MeV having been measured for the first time. The model of vector dominance describes well the data obtained if the
ρ, ρ′, and ρ″ resonances are taken into account. The probability of the decay ρ → π+π−π0π0 is B(ρ → π+π−π0π0) = (1.60 ± 0.74 ± 0.18) × 10−5. The upper limit for the decay ω → π+π−π0π0 has been improved by two orders of magnitude compared to previous measurements and is B(ω → π+π−π0π0) < 2 × 10−4 at a 90% confidence level.
Journal of Experimental and Theoretical Physics 04/2012; 109(3):379-392. · 1.03 Impact Factor
-
M. N. Achasov, K. I. Beloborodov,
A. V. Berdyugin,
A. V. Bozhenok,
D. A. Bukin,
T. V. Dimova,
V. P. Druzhinin,
V. B. Golubev,
I. A. Koop,
A. A. Korol,
S. V. Koshuba,
A. P. Lysenko,
A. V. Otboev,
E. V. Pakhtusova,
S. I. Serednyakov,
Yu. M. Shatunov,
V. A. Sidorov,
Z. K. Silagadze,
A. N. Skrinsky,
A. V. Vasiljev
[show abstract]
[hide abstract]
ABSTRACT: We present a measurement of the e
+
e
− → K
S
K
L cross section in the energy range √s = 1.04−1.38 GeV. For an energy of √s ≥ 1.2 GeV the cross section exceeds vector meson dominance model predictions with only ρ(770), ω(783), and ϕ(1020) mesons
taken into account. The measured cross section agrees well with previous measurements.
Journal of Experimental and Theoretical Physics 04/2012; 103(5):720-727. · 1.03 Impact Factor
-
M. N. Achasov, K. I. Beloborodov,
A. V. Berdyugin,
A. A. Botov,
V. B. Golubev,
T. V. Dimova,
V. P. Druzhinin,
L. V. Kardapoltsev,
A. G. Kharlamov,
D. P. Kovrizhin, [......],
S. V. Koshuba,
A. E. Obrazovsky,
E. V. Pakhtusova,
D. A. Shtol,
S. I. Serednyakov,
Z. K. Silagadze,
A. N. Skrinsky,
Yu. A. Tikhonov,
Yu. M. Shatunov,
A. V. Vasil'ev
[show abstract]
[hide abstract]
ABSTRACT: In an experiment with the Spherical Neutral Detector at VEPP-2M collider the cross section of the process e+e− → π+π−π0π0 was measured. At energies √s < 920 MeV this cross section was measured for the first time. The energy dependence of the cross section is well discribed by the vector dominance model with contributions from ρ, ρ', ρ'' mesons. The decay probability ρ → π +π−π0π0 was found to be Bρ = (1.60±0.74±0.18) × 10−5. The upper limit for the decay ω → π+π−π0π0 was improved by two orders of magnitude compared to the previous measurements and is Bω < 2 × 10−4 at 90% confidence level.
Chinese Physics C 06/2010; 34(6):680. · 0.27 Impact Factor
-
M. N. Achasov, K. I. Beloborodov,
A. V. Bergyugin,
A. G. Bogdanchikov,
A D Bukin,
D. A. Bukin,
T. V. Dimova,
V. P. Druzhinin,
V B Golubev,
I. A. Koop,
A. A. Korol,
S. V. Koshuba,
A. P. Lysenko,
E. V. Pakhtusova,
S I Serednyakov,
Yu. M. Shatunov,
Z. K. Silagadze,
A. N. Skrinsky,
A. V. Vasiljev
[show abstract]
[hide abstract]
ABSTRACT: The search for lepton-flavor-violation process e^+e^-\to e\mu in the energy region \sqrt{s}=984 - 1060 MeV with SND detector at VEPP-2M e^+e^- collider is reported. The model independent 90% CL upper limits on the e^+e^-\to e\mu cross section, \sigma_{e\mu} < 11 pb, as well as on the corresponding \phi\to e\mu branching fraction, B(\phi\to e\mu) < 2 \times 10^{-6}, for the final particles polar angles 55^\circ<\theta<125^\circ, were obtained.
11/2009;
-
M. N. Achasov,
V. M. Aulchenko, K. I. Beloborodov,
A. V. Berdyugin,
A. G. Bogdanchikov,
A D Bukin,
D. A. Bukin,
T. V. Dimova,
V. P. Druzhinin,
V B Golubev, [......],
S. V. Koshuba,
A. P. Lysenko,
E. V. Pakhtusova,
E. A. Perevedentsev,
S I Serednyakov,
Yu. M. Shatunov,
Z. K. Silagadze,
A. N. Skrinsky,
Yu. A. Tikhonov,
A. V. Vasiljev
[show abstract]
[hide abstract]
ABSTRACT: 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. Comment: 29 pages, 23 figures
10/2008;
-
M. N. Achasov, K. I. Beloborodov,
A. V. Berdyugin,
A. G. Bogdanchikov,
A. D. Bukin,
D. A. Bukin,
A. V. Vasil’ev,
V. B. Golubev,
T. V. Dimova,
V. P. Druzhinin,
I. A. Koop,
A. A. Korol’,
S. V. Koshuba,
E. V. Pakhtusova,
E. A. Perevedentsev,
S. I. Serednyakov,
Z. K. Silagadze,
A. N. Skrinsky,
Yu. M. Shatunov
[show abstract]
[hide abstract]
ABSTRACT: The e
+
e
− → ω, ρ → π0
e
+
e
− processes have been investigated in the experiments with Spherical Neutral Detector at the VEPP-2M e
+
e
− collider. The measurements provide the probability ℬ(ω → π0
e
+
e
−) = (0.761 ± 0.053 ± 0.064) × 10−3 of the ω → π0
e
+
e
g- conversion decay and the upper limit ℬ(ρ → π0
e
+
e
−) < 1.2 × 10−5 (at 90% CL) for the ρ → π0
e
+
e
− decay. The transition form factor was measured at three values of the 4-momentum transfer squared.
Journal of Experimental and Theoretical Physics 06/2008; 107(1):61-68. · 1.03 Impact Factor
-
M. N. Achasov, K. I. Beloborodov,
A. V. Berdyugin,
A. G. Bogdanchikov,
A. D. Bukin,
D. A. Bukin,
T. V. Dimova,
V. P. Druzhinin,
V. B. Golubev,
A. A. Korol,
S. V. Koshuba,
E. V. Pakhtusova,
S. I. Serednyakov,
Z. K. Silagadze,
A. V. Vasiljev
[show abstract]
[hide abstract]
ABSTRACT: In the experiment with the SND detector at the VEPP-2M e+e- collider measuring the e+e-→ηγ cross section in the energy range 0.6<√s<1.38 GeV the reanalysis of data is performed. The goal is to improve the accuracy of the previous results by analyzing ambiguities in the approximation of energy dependence of the e+e-→ηγ cross section, which were not taken into account in our previous study. We report new results on the approximation of the e+e-→ηγ cross section based on the vector dominance model under new model parameter assumptions.
Phys. Rev. D. 10/2007; 76(7).
-
M. N. Achasov, K. I. Beloborodov,
A. V. Berdyugin,
A. G. Bogdanchikov,
A D Bukin,
D. A. Bukin,
T. V. Dimova,
V. P. Druzhinin,
V B Golubev,
A. A. Korol,
S. V. Koshuba,
E. V. Pakhtusova,
S I Serednyakov,
Z. K. Silagadze,
A. V. Vasiljev
[show abstract]
[hide abstract]
ABSTRACT: In the experiment with the SND detector at the VEPP-2M $e^+e^-$ collider measuring the $e^+e^-\to \eta\gamma$ cross section in the energy range $0.6<\sqrt{s}<1.38 \mathrm{GeV}$ the reanalysis of data is performed. The goal is to improve the accuracy of the previous results by analysing ambiguities in the approximation of energy dependence of the $e^+e^-\to \eta\gamma$ cross section, which were not taken into account in our previous study. We report new results on the approximation of the $e^+e^-\to \eta\gamma$ cross section based on Vector Dominance Model under new model parameter assumptions.
10/2007;
-
M. N. Achasov, K. I. Beloborodov,
A. V. Berdyugin,
A. G. Bogdanchikov,
A D Bukin,
D. A. Bukin,
T. V. Dimova,
V. P. Druzhinin,
V B Golubev,
I. A. Koop,
A. A. Korol,
S. V. Koshuba,
E. V. Pakhtusova,
E. A. Perevedentsev,
S I Serednyakov,
Yu. M. Shatunov,
Z. K. Silagadze,
A. N. Skrinsky,
Yu. V. Usov,
A. V. Vasiljev
[show abstract]
[hide abstract]
ABSTRACT: The cross section of the process $e^+e^- \to K^+K^-$ was measured in the energy range $\sqrt{s}$ = 1.04--1.38 GeV in the SND experiment at the VEPP-2M $e^+e^-$ collider. The measured cross section is described by the model of vector meson dominance with contributions from the light vector mesons $\rho$, $\omega$, $\phi$ and their lowest excitations. The mean statistical accuracy of the measurement is 4.4 %, and the systematic uncertainty is 5.2 %.
08/2007;
-
M. N. Achasov,
V. M. Aulchenko, K. I. Beloborodov,
A. V. Berdyugin,
A. G. Bogdanchikov,
A. V. Bozhenok,
D. A. Bukin,
T. V. Dimova,
V. P. Druzhinin,
V. B. Golubev,
A. A. Korol,
S. V. Koshuba,
A. V. Otboev,
E. V. Pakhtusova,
S. I. Serednyakov,
Yu. M. Shatunov,
V. A. Sidorov,
Z. K. Silagadze,
A. N. Skrinsky,
A. V. Vasiljev
[show abstract]
[hide abstract]
ABSTRACT: In experiment with the SND detector at the VEPP-2M e+e- collider the e+e-→ηγ cross section was measured in the center-of-mass 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′(1465) resonances and agrees with results of previous measurements. The decay probabilities B(ϕ→ηγ), B(ω→ηγ) and B(ρ→ηγ) were measured with the accuracies better than or comparable to the world averages.
Phys. Rev. D. 07/2006; 74(1).
-
M. N. Achasov, K. I. Beloborodov,
A. V. Berdyugin,
A. V. Bozhenok,
D. A. Bukin,
T. V. Dimova,
V. P. Druzhinin,
V B Golubev,
I. A. Koop,
A. A. Korol,
S. V. Koshuba,
A. P. Lysenko,
A. V. Otboev,
E. V. Pakhtusova,
S I Serednyakov,
Yu. M. Shatunov,
V. A. Sidorov,
Z. K. Silagadze,
A. N. Skrinsky,
A. V. Vasiliev
[show abstract]
[hide abstract]
ABSTRACT: We present a measurement of the $e^+e^-\to K_SK_L$ cross section in the energy range $\sqrt{s}=1.04 \div 1.38$ GeV. For the energy $\sqrt{s}\geq 1.2$ GeV the cross section exceeds vector meson dominance model predictions with only $\rho(770)$, $\omega(783)$, and $\phi(1020)$ mesons taken into account. Measured cross section agrees well with previous measurements. Comment: 15 pages, 5 figures
06/2006;
-
M. N. Achasov,
V. M. Aulchenko, K. I. Beloborodov,
A. V. Berdyugin,
A. G. Bogdanchikov,
A. V. Bozhenok,
D. A. Bukin,
T. V. Dimova,
V. P. Druzhinin,
V B Golubev,
A. A. Korol,
S. V. Koshuba,
A. V. Otboev,
E. V. Pakhtusova,
S I Serednyakov,
Yu. M. Shatunov,
V. A. Sidorov,
Z. K. Silagadze,
A. N. Skrinsky,
A. V. Vasiljev
[show abstract]
[hide abstract]
ABSTRACT: In experiment with the SND detector at VEPP-2M $e^+e^-$ collider the $e^+e^-\to\eta\gamma$ 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 $\rho(770)$, $\omega(783)$, $\phi(1020)$, $\rho^{\prime}(1465)$ resonances and agrees with results of previous measurements. The decay probabilities $\BR(\phi\to\eta\gamma)$, $\BR(\omega\to\eta\gamma)$ and $\BR(\rho\to\eta\gamma)$ were measured with the accuracies better than or comparable to the world averages.
06/2006;
-
M. N. Achasov, K. I. Beloborodov,
A. V. Berdyugin,
A. G. Bogdanchikov,
A. V. Bozhenok,
A D Bukin,
D. A. Bukin,
T. V. Dimova,
V. P. Druzhinin,
V B Golubev,
A. A. Korol,
S. V. Koshuba,
E. V. Pakhtusova,
S I Serednyakov,
Yu. M. Shatunov,
V. A. Sidorov,
Z. K. Silagadze,
A. N. Skrinsky,
Yu. A. Tikhonov,
A. V. Vasiljev
[show abstract]
[hide abstract]
ABSTRACT: The corrected cross section of the e^+e^-\to\pi^+\pi^- process measured in the SND experiment at the VEPP-2M e^+e^- collider is presented. The update is necessary due to a flaw in the e^+e^-\to\pi^+\pi^- and e^+e^-\to\mu^+\mu^- Monte Carlo events generators used previously in data analysis. Comment: 10 pages,7 figures
05/2006;
-
M. N. Achasov, K. I. Beloborodov,
A. V. Berdyugin,
A. G. Bogdanchikov,
A. V. Bozhenok,
A D Bukin,
D. A. Bukin,
T. V. Dimova,
V. P. Druzhinin,
V B Golubev,
A. A. Korol,
S. V. Koshuba,
E. V. Pakhtusova,
S I Serednyakov,
Yu. M. Shatunov,
V. A. Sidorov,
Z. K. Silagadze,
A. N. Skrinsky,
Yu. A. Tikhonov,
A. V. Vasiljev
[show abstract]
[hide abstract]
ABSTRACT: The update of the e^+e^-\to\pi^+\pi^- process cross section, measured in the energy region \sqrt{s}<1 GeV with SND detector at VEPP-2M collider is presented. Comment: Talk given at Int. Workshop e+e- Collisions from phi to psi, February 27 - March 2, 2006
04/2006;
-
S I Serednyakov,
M. N. Achasov, K. I. Beloborodov,
A. G. Bogdanchikov,
A. V. Bozhenok,
A D Bukin,
D. A. Bukin,
T. V. Dimova,
V. P. Druzhinin,
V B Golubev,
A. A. Korol,
S. V. Koshuba,
E. V. Pakhtusova,
Yu. M. Shatunov,
V. A. Sidorov,
Z. K. Silagadze,
A. N. Skrinsky,
Yu. A. Tikhonov,
A. V. Vasiljev
[show abstract]
[hide abstract]
ABSTRACT: New results of the e+e- -> pi+pi-, K+K-, K_SK_L, pi0/gamma, eta0/gamma processes cross section measurements are presented. The results are based on the 30 pb^-1 data, accumulated by SND detector at VEPP-2M e+e- collider in the energy range sqrt(s)=0.4-1.4 GeV during 1995-2000 years. The comparison with existing experimental data shows that the measurement accuracy is close to or better than the world average. For the e+e- -> pi+pi- process the accuracy is about 0.01. This is important for calculation of hadronic contribution into the muon anomalous magnetic moment.
01/2006;
-
M. N. Achasov, K. I. Beloborodov,
A. V. Berdyugin,
A. G. Bogdanchikov,
A. V. Bozhenok,
A. D. Bukin,
D. A. Bukin,
T. V. Dimova,
V. P. Druzhinin,
V. B. Golubev,
A. A. Korol,
S. V. Koshuba,
E. V. Pakhtusova,
S. I. Serednyakov,
Yu. M. Shatunov,
V. A. Sidorov,
Z. K. Silagadze,
A. N. Skrinsky,
Yu. A. Tikhonov,
A. V. Vasiljev
[show abstract]
[hide abstract]
ABSTRACT: The corrected cross section of the e
+
e
− → π+π− process measured in the spherical neutral detector experiment at the VEPP-2M e
+
e
− collider is presented. The update is necessary due to a flaw in the e
+
e
− → π+π− and e
+
e
− → μ+μ− Monte Carlo event generators used previously in data analysis.
Journal of Experimental and Theoretical Physics 01/2006; 103(3):380-384. · 1.03 Impact Factor
-
M. N. Achasov, K. I. Beloborodov,
A. V. Berdyugin,
A. G. Bogdanchikov,
A. V. Bozhenok,
A D Bukin,
D. A. Bukin,
T. V. Dimova,
V. P. Druzhinin,
V B Golubev, [......],
A. P. Lysenko,
A. V. Otboev,
E. V. Pakhtusova,
S I Serednyakov,
Yu. M. Shatunov,
V. A. Sidorov,
Z. K. Silagadze,
A. N. Skrinsky,
Yu. A. Tikhonov,
A. V. Vasiljev
[show abstract]
[hide abstract]
ABSTRACT: The cross section of the process e^+e^-\to \pi^+\pi^- was measured in the SND experiment at the VEPP-2M collider in the energy region 400<\sqrt[]{s}<1000 MeV. This measurement was based on about 12.4 \times 10^6 selected collinear events, which include 7.4\times 10^6 e^+e^-\to e^+e^-, 4.5\times 10^6 e^+e^-\to\pi^+\pi^- and 0.5\times 10^6 e^+e^-\to\mu^+\mu^- selected events. The systematic uncertainty of the cross section determination is 1.3 %. The \rho-meson parameters were determined: m_\rho=774.9\pm 0.4\pm 0.5 MeV, \Gamma_\rho=146.5\pm 0.8\pm 1.5 MeV, \sigma(\rho\to\pi^+\pi^-)=1220\pm 7\pm 16 nb as well as the parameters of the G-parity suppressed decay \omega\to\pi^+\pi^-: \sigma(\omega\to\pi^+\pi^-)=29.9\pm 1.4\pm 1.0 nb and \phi_{\rho\omega} = 113.5\pm 1.3\pm 1.7 degree. Comment: 30 pages REVTEX and 31 figures
06/2005;
-
M. N. Achasov, K. I. Beloborodov,
A. V. Berdyugin,
A. G. Bogdanchikov,
A. V. Bozhenok,
A. D. Bukin,
D. A. Bukin,
T. V. Dimova,
V. P. Druzhinin,
V. B. Golubev, [......],
A. P. Lysenko,
A. V. Otboev,
E. V. Pakhtusova,
S. I. Serednyakov,
Yu. M. Shatunov,
V. A. Sidorov,
Z. K. Silagadze,
A. N. Skrinsky,
Yu. A. Tikhonov,
A. V. Vasiljev
[show abstract]
[hide abstract]
ABSTRACT: The cross section of the process e
+
e
− → π+π− was measured in the spherical neutral detector experiment at the VEPP-2M collider in the energy region
400 < Ös < 1000 MeV400 < \sqrt s < 1000 MeV
. This measurement was based on about 12.4 × 106 selected collinear events, which include 7.4 × 106
e
+
e
− → e
+
e
−, 4.5 × 106
e
+
e
− → π+π−, and 0.5 × 106
e
+
e
− → μ+μ− selected events. The systematic uncertainty of cross section determination is 1.3%. The ρ-meson parameters were determined
as m
ρ
= 774.9±0.4±0.5 MeV, Γ
ρ
= 146.5±0.8±1.5 MeV, and σ(ρ → π+π−) = 1220 ± 7 ± 16 nb and the parameters of the G-parity suppressed decay ω → π+π− as σ(ω → π+π−) = 29.9 ± 1.4 ± 1.0 nb and φρω = 113.5±1.3±1.7°.
Journal of Experimental and Theoretical Physics 01/2005; 101(6):1053-1070. · 1.03 Impact Factor
