We present current status of the SND and CMD-3 experiments at the VEPP-2000
e
+
e
−
collider and recent result of data analysis on the processes $e^+e^-\rightarrow\pi^+\pi^-,n\overline ...n,\pi^+\pi^-\eta,\pi^+\pi^-\pi^0\eta,K_SK_L\pi^0$, etc.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
The CMD-3 detector has been successfully collecting data at the electron-positron collider VEPP-2000 since December 2010. The first scan below 1 GeV for a π
+
π
−
measurement was performed in 2013. ...The collected data sample corresponds to about 18 pb
−1
of integrated luminosity in this energy range. Analysis of the
e
+
e
−
→ π
+
π
−
cross section is in progress. Status of this measurement are presented.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
The data sample collected in 2011-2013 at the c.m.s. energies between 0.32-2 GeV with the CMD-3 detector operating at the VEPP-2000
e
+
e
−
collider is analzed. The collected data corresponds to an ...integrated luminosity about ∼ 60
pb
−1
. The techniques for determination of the integrated luminosity for each energy setting is described. Some preliminary results of the study of the processes
e
+
e
−
→
K
+
K
−
+
n
π (n = 1,2,3) with two charged kaons in the final state are presented. These processes have several intermediate states, which are important to correctly descript the angular distributions of final particles and the cross sections dependence on the energy.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
The CMD-3 detector started data taking at the electron-positron collider VEPP-2000 1 in December 2010. The collected data sample corresponds to an integrated luminosity of 87 pb
−1
in the c.m. energy ...range from 1.06 up to 2 GeV and 91 pb
−1
from 0.32 to 1.06 GeV. The integrated luminosity was measured by counting
e
+
e
−
→
e
+
e
−
and
e
+
e
−
→ γγ events, allowing additional photons in the final state. Preliminary results of the luminosity measurement are presented for various energy ranges and its accuracy is estimated to be 1%.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
A
bstract
The cross section of the process
e
+
e
−
→ ηπ
+
π
−
is measured using the data collected with the CMD-3 detector at the VEPP-2000 collider in the center-of-mass energy range from 1
.
1 to 2
....
0 GeV. The decay mode
η → γγ
is used for
η
meson reconstruction in the data sample corresponding to an integrated luminosity of 78
.
3 pb
−
1
. The energy dependence of the
e
+
e
−
→ ηπ
+
π
−
cross section is fitted within the framework of vector meson dominance in order to extract the Γ(
ρ
(1450)
→ e
+
e
−
)
B
(
ρ
(1450)
→ ηπ
+
π
−
) and the Γ(
ρ
(1700)
→ e
+
e
−
)
B
(
ρ
(1700)
→ ηπ
+
π
−
) products. Based on conservation of vector current, the analyzed data are used to test the relationship between the
e
+
e
−
→ ηπ
+
π
−
cross section and the spectral function in
τ
−
→ ηπ
−
π
0
ντ
decay. The
e
+
e
−
→ ηπ
+
π
−
cross section obtained with the CMD-3 detector is in good agreement with the previous measurements.
An 800
l liquid xenon scintillation
γ
-ray detector is being developed for the MEG experiment which will search for
μ
+
→
e
+
γ
decay at the Paul Scherrer Institut. Absorption of scintillation light ...of xenon by impurities might possibly limit the performance of such a detector. We used a 100
l prototype with an active volume of
372
×
372
×
496
mm
3
to study the scintillation light absorption. We have developed a method to evaluate the light absorption, separately from elastic scattering of light, by measuring cosmic rays and
α
sources. By using a suitable purification technique, an absorption length longer than 100
cm has been achieved. The effects of the light absorption on the energy resolution are estimated by Monte Carlo simulation.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
The cross-section of the process e+e−→π+π− has been measured using about 114000 events collected by the CMD-2 detector at the VEPP-2M e+e− collider in the center-of-mass energy range from 0.61 to ...0.96 GeV. Results of the pion form factor determination with a 0.6% systematic uncertainty are presented. The following values of the ρ- and ω-meson parameters were found: Mρ=(776.09±0.81) MeV, Γρ=(144.46±1.55) MeV, Γ(ρ→e+e−)=(6.86±0.12) keV, Br(ω→π+π−)=(1.33±0.25)%. Implications for the hadronic contribution to the muon anomalous magnetic moment are discussed.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Since December 2010 the CMD-3 and SND detectors detectors collect data at the VEPP-2000 electron-positron collider. In 2013-2015 the injection facility of the collider has undergone an upgrade of the ...injection system. The new BINP injection complex has been connected to the VEPP-2000 collider, so the restrictions connected to the lack of positrons and limited beam energy transfer do not apply any more. The collider luminosity in whole energy range is restricted now only by beam-beam effects. VEPP-2000 collider started to collect data with two detectors at 2016 year. The collected data sample since 2010 corresponds more than 100 pb
-1
of integrated luminosity per detector in the c.m. energy between 0.32 and 2GeV. We will report here results of analysis of various hadronic cross sections from detectors both published and preliminary. These measurements are important by themselves and also because of the implications for anomaly of the magnetic moment of a muon (g-2) discrepancy.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
This paper reports measurements of the hadronic cross sections with the CMD-3 detector at the VEPP-2000 electron-positron collider. The overall size of the data sample analyzed is about 60 pb-1, ...collected by the CMD- 3 running since December 2010 up to June 2013 in the c.m. energy range from 0.32 to 2.0 GeV. The preliminary results of data analysis for various modes of e+e−→hadrons are discussed.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
40.
Calorimetry of the CMD-3 detector Akhmetshin, R R; Anisenkov, A V; Aulchenko, V M ...
Journal of physics. Conference series,
11/2017, Volume:
928, Issue:
1
Journal Article
Peer reviewed
Open access
The CMD-3 detector has been collecting data since 2010 at the e+e− collider VEPP-2000 in the Budker Institute of Nuclear Physics. VEPP-2000 uses the novel round beam technique and provides high ...luminosity in a wide c.m.energy range from 0.32 to 2 GeV. The physics goal of the CMD-3 experiment is a study of the e+e− annihilation into hadrons. CMD-3 is a general-purpose detector, which provides high efficiency for both charged and neutral particles. The electromagnetic calorimeter consists of the barrel calorimeter based on liquid xenon and CsI crystals, and the endcap calorimeter based on BGO crystals. The main parameters of the calorimeters are presented.
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