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.
A study of hadron production at the nucleon-antinucleon threshold has been performed with the CMD-3 detector at the VEPP-2000
e
+
e
−
collider. A very fast rise with an about 1 MeV width has been ...observed in the
e
+
e
−
→
pp
̅ cross section. A sharp drop in the
e
+
e
−
→ 3(π
+
π
−
) cross section has been con?rmed and found to have a width of less than 2 MeV, in agreement with the observed fast rise of the
e
+
e
−
→
pp
̅ cross section. For the ?rst time a similar sharp drop is demonstrated in the
e
+
e
−
→
K
+
K
−
π
+
π
−
cross section. The behavior of the
e
+
e
−
→ 3(π
+
π
−
),
K
+
K
−
π
+
π
−
cross sections cannot be explained by an interference of any resonance amplitude with continuum, therefore this phenomenon cannot be due to a narrow near-threshold resonance. No such structure has been observed in the
e
+
e
−
→ 2(π
+
π
−
) cross section.
A large data sample of
e
+
e
-
→ 4π collected by the CMD-3 experiment at the VEPP-2000
e
+
e
−
collider allowed for an amplitude analysis of the process
e
+
e
−
→ 4π in the center-of-mass energy ...range 900–2000 MeV. Various intermediate components were distinguished and dominance of the ωπ
0
and a
1
π amplitudes has been proved.
Recent results from the CMD-3 detector Lukin, P.A.; Akhmetshin, R.R.; Amirkhanov, A.N. ...
Nuclear and particle physics proceedings,
January-March 2020, 2020-01-00, Volume:
309-311
Journal Article
Peer reviewed
This paper reports a current status of the measurements of the hadronic cross sections in the c.m. energy range from 0.32 to 2.0 GeV with the CMD-3 detector at the VEPP-2000 electron-positron ...collider. The overall size of the data, acquired by the CMD-3 in the runs of 2010–2013 and 2017–2018 years, is about 160 pb−1. The results of data analysis for various exclusive modes of e+e−→hadrons are described.
The process e+e−→K+K−η has been studied in the center-of-mass energy range from 1.59 to 2.007 GeV using the data sample of 59.5 pb−1, collected with the CMD-3 detector at the VEPP-2000 e+e− collider ...in 2011, 2012 and 2017. The K+K−η final state is found to be dominated by the contribution of the ϕ(1020)η intermediate state. The cross section of the process e+e−→ϕ(1020)η has been measured with a systematic uncertainty of 5.1% on the base of 3009 ± 67 selected events. The obtained cross section has been used to calculate the contribution to the anomalous magnetic moment of the muon: aμϕη(E<1.8GeV)=(0.321±0.015stat±0.016syst)×10−10, aμϕη(E<2.0GeV)=(0.440±0.015stat±0.022syst)×10−10. From the cross section approximation the ϕ(1680) meson parameters have been determined with better statistical precision, than in previous studies.
A search for the process
e
+
e
−
→
D
*0
(2007) has been performed with the CMD-3 detector at the VEPP-2000
e
+
e
−
-collider. Two main decay modes of the
D
*0
(2007) decay,
D
0
π
0
and
D
0
γ, ...followed by
D
0
→
K
+
π
−
π
+
π
−
are used in this analysis. With an integrated luminosity of 3.7 pb
−1
collected at the center-of-mass energy E
c.m.
=2006.62 MeV our preliminary upper limit is B
D*
0
→
e
+
e
−
<1.6× 10
−6
at 90%C.L.
The cross section of the process
e
+
e
−
→ π
+
π
−
π
+
π
−
has been measured using an integrated luminosity of 17 pb
−1
collected with the CMD-3 detector in the center-of-mass energy range 650-1000 ...MeV. High-precision measurements of various hadronic cross sections are of great interest in relation with the problem of the muon anomalous magnetic moment g-2. This measurement can be also used to test the relation between the cross section of
e
+
e
−
→ π
+
π
−
π
+
π
−
and the spectral function for the τ
−
→ π
−
π
0
π
0
π
0
decay predicted by the conservation of vector current (CVC).
The process e+e−→K+K−π+π− has been studied in the center-of-mass energy range from 1500 to 2000 MeV using a data sample of 23 pb−1 collected with the CMD-3 detector at the VEPP-2000 e+e− collider. ...Using about 24 000 selected events, the e+e−→K+K−π+π− cross section has been measured with a systematic uncertainty decreasing from 11.7% at 1500–1600 MeV to 6.1% above 1800 MeV. A preliminary study of K+K−π+π− production dynamics has been performed.
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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