Since 2010 the CMD-3 detector has been collecting data at the e+e− collider VEPP-2000 in the Budker Institute of Nuclear Physics. One of the main goals of experiments with CMD-3 detector is the ...precise measurement of the cross sections of the e+e− annihilation into hadrons. For a large number of processes the main source of systematic uncertainty in cross sections determination due to accuracy of polar angles determination of the tracks. Z-chamber is used for the reconstruction of the track longitudinal coordinate which is with low systematic uncertainty. The measurement of longitudinal coordinates is performed by the collecting of the charge which is induced on the strip cathodes of the Z-chamber. The algorithms of the reconstruction of cathodes clusters and calibration procedure are presented.
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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CMD-3 Overview Logashenko, Ivan B.; Ignatov, F.V.; Akhmetshin, R.R. ...
EPJ Web of Conferences,
2019, Volume:
218
Journal Article, Conference Proceeding
Peer reviewed
Open access
The CMD-3 detector is installed at the VEPP-2000
e
+
e
−
collider at BINP (Novosibirsk, Russia). It is a general-purpose detector, equipped with a tracking system, two crystal (CSI and BGO) ...calorimeters, liquid Xe calorimeter, TOF and muon systems. The main goal of experiments at CMD-3 is a study of exclusive modes of
e
+
e
−
→
hadrons
at energies $ \sqrt s \le $ GeV. In particular, these results provide an important input for calculation of the hadronic contribution to the muon anomalous magnetic moment.
The first round of data taking was performed in 2011–2013, when about 60 1/pb were taken in the center-of-mass (c.m.) energy range from 0.32 to 2.0 GeV. Here we present a survey of results of data analysis.
Between 2013 and 2016 the collider and the detector were upgraded. The data taking resumed by the end of 2016. In the first run after the upgrade about 50 1/pb were collected at the energy range between 1.28 and 2.007 GeV. We discuss the upgrade and the first preliminary results from the new data.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
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
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.
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