VEPP-2000 is electron-positron collider exploiting the novel concept of round colliding beams. After three seasons of data taking in the whole energy range of 160 1000 MeV per beam it was stopped in 2013 for injection chain upgrade. The linking to the new BINP source of intensive beams together with booster synchrotron modernization provides the drastic luminosity gain at top energy
The process $$e^+e^-\rightarrow \eta \pi ^0\gamma $$
e
+
e
-
→
η
π
0
γ
is studied in the center-of-mass energy range 1.05–2.00 GeV using data with an integrated luminosity of 94.5 $$\hbox {pb}^{-1}$$
pb
-
1
collected by the SND detector at the VEPP-2000 $$e^{+}e^{-}$$
e
+
e
-
collider. The $$e^+e^-\rightarrow \eta \pi ^0\gamma $$
e
+
e
-
→
η
π
0
γ
cross section is measured for the first time. It is shown that the dominant mechanism of this reaction is the transition through the $$\omega \eta $$
ω
η
intermediate state. The measured cross section of the subprocess $$e^+e^-\rightarrow \omega \eta \rightarrow \eta \pi ^0\gamma $$
e
+
e
-
→
ω
η
→
η
π
0
γ
is consistent with previous measurements in the $$e^+e^-\rightarrow \pi ^+\pi ^-\pi ^0\eta $$
e
+
e
-
→
π
+
π
-
π
0
η
mode. It is found, with a significance of $$5.6\sigma $$
5.6
σ
, that the process $$e^+e^-\rightarrow \eta \pi ^0\gamma $$
e
+
e
-
→
η
π
0
γ
is not completely described by hadronic vector-pseudoscalar intermediate states. The cross section of this missing contribution, which can originate from radiation processes, e. g. $$e^+e^-\rightarrow a_{0}(1450)\gamma $$
e
+
e
-
→
a
0
(
1450
)
γ
, is measured. It is found to be 15–20 pb in the wide energy range from 1.3 to 1.9 GeV.
The dynamics of the process $$ e^+e^- \rightarrow \pi ^+\pi ^-\pi ^0 $$
e
+
e
-
→
π
+
π
-
π
0
is studied in the energy region from 1.15 to 2.00 GeV using data accumulated with the SND detector at the VEPP-2000 $$e^+e^-$$
e
+
e
-
collider. The Dalitz plot distribution and $$\pi ^+\pi ^-$$
π
+
π
-
mass spectrum are analyzed in a model including the intermediate states $$\rho (770)\pi $$
ρ
(
770
)
π
, $$\rho (1450)\pi $$
ρ
(
1450
)
π
, and $$\omega \pi ^0$$
ω
π
0
. As a result, the energy dependences of the $$\rho (770)\pi $$
ρ
(
770
)
π
and $$\rho (1450)\pi $$
ρ
(
1450
)
π
cross sections and the relative phases between the $$\rho (770)\pi $$
ρ
(
770
)
π
amplitude and the $$\rho (1450)\pi $$
ρ
(
1450
)
π
and $$\omega \pi ^0$$
ω
π
0
amplitudes are obtained. The $$\rho (1450)\pi $$
ρ
(
1450
)
π
cross section has a peak in the energy region of the $$\omega (1650)$$
ω
(
1650
)
resonance (1.55–1.75 GeV). In this energy range the contributions of the $$\rho (770)\pi $$
ρ
(
770
)
π
and $$\rho (1450)\pi $$
ρ
(
1450
)
π
states are of the same order of magnitude. No resonance structure near 1.65 GeV is observed in the $$\rho (770)\pi $$
ρ
(
770
)
π
cross section. We conclude that the intermediate state $$\rho (1450)\pi $$
ρ
(
1450
)
π
gives a significant contribution to the decay of $$\omega (1650)\rightarrow \pi ^+\pi ^-\pi ^0$$
ω
(
1650
)
→
π
+
π
-
π
0
, whereas the $$\rho (770)\pi $$
ρ
(
770
)
π
mechanism dominates in the decay $$\omega (1420)\rightarrow \pi ^+\pi ^-\pi ^0$$
ω
(
1420
)
→
π
+
π
-
π
0
.
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