Existing Monte-Carlo generators with radiative corrections to the
e
+
e
-
→π
+
π
-
process are usually developed under the assumption that pions can be treated as pointlike particles. We study the
e
...+
e
-
→π
+
π
-
γ
process with final-state radiation and test this assumption using simulated events from the MCGPJ generator based on the scalar QED hypothesis. In order to increase a fraction of events with FSR, the analysis was performed in the energy region to the left from the
ρ
-meson peak (660÷785 MeV) that is based on the integrated luminosity of about 8.4 pb
-1
. The experimental data for the photon energy spectrum agree with the simulation results at 1% level.
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.
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.
The preliminary results of measurement of the
e
+
e
−
→ π
+
π
−
π
0
cross section in the 1.05–2 GeV center-of-mass energy range with 30 pb
–1
of experimental data collected using the CMD-3 detector ...are presented. The parameters of resonant states ω(1420) and ω(1650) are obtained.
The process
e
+
e
−
→
K
+
K
−
π
0
has been studied in the center-of-mass energy range from 1.2 to 2 GeV using a 80.6 pb
−1
data sample collected with the CMD-3 detector at the electron-positron ...collider VEPP-2000. Preliminary results of the cross-section measurement are presented.
The cross section of the process e super(+)e super(-) arrow right 3( pi super(+) pi super(-))e+e- arrow right 3( pi + pi -) has been measured using a data sample of 22 pb super(-1)22 pb-1 collected ...with the CMD-3 detector at the VEPP-2000 e super(+)e super(-)e+e- collider. 7956 signal events are selected in the center-of-mass energy range 1.5-2.0 GeV. The measured cross section exhibits a sharp drop near the ppmacr threshold. A first study of dynamics of six-pion production has been performed.
We report preliminary results on the cross section of the process e
+
e
−
→ φ(1020)η measured at 30 center-of-mass energy points in the range from 1.59 up to 2.0 GeV. Data analysis is based on the ...integrated luminosity of 22 pb
−1
collected with the CMD-3 detector in 2011–2012. The obtained cross section agrees with the BaBar measurement and has better statistical accuracy.
The preliminary results of measurement of the e{sup +} e{sup −} → π{sup +}π{sup −}π{sup 0} cross section in the 1.05–2 GeV center-of-mass energy range with 30 pb{sup –1} of experimental data ...collected using the CMD-3 detector are presented. The parameters of resonant states ω(1420) and ω(1650) are obtained.
We analyze the data on
e
+
e
−
collisions at c.m.s. energies between 0.32 and 2 GeV collected in 2011–2013 with the CMD3 detector operating at the VEPP-3
e
+
e
−
collider of the Budker Institute of ...Nuclear Physics. The data correspond to an integrated luminosity of nearly 60 pb
-1
. Preliminary results
e
+
e
−
→
K
+
K
−
n
π (
n
= 1, 2, 3) on the reactions with two charged kaons in the final state are presented, and the procedure for estimating the integrated luminosity for each energy setting is described.
Experiments with the CMD-3 detector at the VEPP-2000 electron–positron collider in the range of center of mass collision energies from 0.32 to 2 GeV have been performed since December 2010. The ...amount of accumulated data corresponds to an integrated luminosity of about 60 pb
-1
. The resultsof a preliminary analysis are presented for the following annihilation channels:
e
+
e
-
→ 3(π
+
π
-
), 2(π
+
π
-
π
0
),
K
+
K
-
π
+
π
-
,
K
+
K
-
,
, and π
+
π
-
. Since processes of electron–positron annihilation that involve the production of multihadron states proceed through several intermediate states, their analysis is necessary for the correct description of the emission-angle and invariant-mass distributions of product particles.
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