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.
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.
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.
Calorimetry of the CMD-3 detector Shebalin, V.E.; Akhmetshin, R.R.; Anisenkov, A.V. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
07/2016, Volume:
824
Journal Article
Peer reviewed
CMD-3 is a general purpose detector designed to study e+e− annihilation into hadrons. It is mounted at VEPP-2000 collider which operates in the wide energy range, Ec.m.s=0.32−2GeV. The calorimetry at ...the detector is based on three subsystems: closest to the beam pipe barrel Liquid Xenon calorimeter, outer barrel calorimeter based on CsI scintillation crystals and the endcap calorimeter made of BGO scintillation crystals. We describe the structure of the calorimeters, their electronics and the energy calibration procedures.
The ϕ(1020) meson leptonic width has been determined from the combined analysis of 4 major decay modes of the resonance (ϕ→K+K−,KL0KS0,π+π−π0,ηγ) studied with the CMD-2 detector at the VEPP-2M e+e− ...collider. The following value has been obtained: Γ(ϕ→e+e−)=1.235±0.006±0.022 keV. The ϕ(1020) meson parameters in four main decay channels have been also recalculated: B(ϕ→K+K−)=0.493±0.003±0.007, B(ϕ→KLKS)=0.336±0.002±0.006, B(ϕ→π+π−π0)=0.155±0.002±0.005, B(ϕ→ηγ)=0.0138±0.0002±0.0002.
A thin superconducting solenoid is designed to provide a magnetic field of 1.5 T in the CMD-3 detector. The solenoid and an LXe calorimeter are placed in the common vacuum vessel of the detector. The ...solenoid is passively protected by subdivision and inductive coupling methods. The radiation thickness of the coil is 0.085X 0 , and the achieved E/M ratio is 6.9 kJ/kg. In 2007, the solenoid was tested in a prototype iron yoke, where the operational parameters were achieved. This paper reports the performance of the solenoid in the CMD-3 detector. The solenoid has been operated safely at a 1.35-T magnetic field. There were 19 quenches caused by various factors at magnetic fields in the range of 0.6-1.38 T. After a quench, the solenoid absorbed about 40% of the stored energy and warmed up to 42-55 K. A significant influence of quench-induced eddy currents on the detector design elements was observed. Liquid helium consumption at steady operation was about 3.5 L/h. Possible application of the achieved results to designing thinner solenoids is discussed.
A brief review of the recent results on the hadronic cross section measurements with the CMD-3 detector at the
e
+
e
−
collider VEPP-2000 is given. Focus is made on the processes with charged kaons ...in multihadron events, which have a strong impact on strange meson spectroscopy and form factors that are important ingredients in the Dalitz plot analysis. Experimental data relevant to the topic are presented from the broad energy range covered by VEPP-2000 and compared to earlier measurements by the different collaborations. The analysis is based on the integrated luminosity of about 100 pb
−1
collected in 2011, 2012 and 2017.
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.
The superconducting solenoid is designed to provide 1.5 T magnetic field in the CMD-3 detector. Its dimensions are 0.7 m in diameter and 0.9 m in length. The superconducting coil is made of two ...layers of NbTi/Cu cable 0.87 mm in diameter. The solenoid is protected from quench by shunts, which are uniformly distributed along the coil. The total resistance of the shunts is about 40 . The superconducting coil has a minimal radiation thickness compared with other solenoids (0.085 ). The superconducting coil is indirectly cooled by liquid helium being in nucleate pool boiling state at 4.2 K. High purity aluminum strips were used to keep the solenoid at 4.2 K. The magnet system was tested for liquid helium efficiency. In May 2007, the solenoid, surrounded by a dummy iron yoke, was charged to its design current. The quench behavior of the solenoid is discussed.
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