Abstract
We study the process
e
+
e
−
→
π
+
π
−
η
γ
, where the photon is radiated from the initial state. About 8000 fully reconstructed events of this process are selected from the BABAR data sample with an integrated luminosity of
469
fb
−
1
. Using the
π
+
π
−
η
invariant mass spectrum, we measure the
e
+
e
−
→
π
+
π
−
η
cross section in the
e
+
e
−
center-of-mass energy range from 1.15 to 3.5 GeV. The cross section is well described by the Vector-Meson dominance model with four
ρ
-like states. We observe
49
±
9
events of the
J
/
ψ
decay to
π
+
π
−
η
and measure the product
Γ
J
/
Ψ
→
e
+
e
−
B
J
/
Ψ
→
π
+
π
−
η
=
2.34
±
0.4
3
stat
±
0.1
6
syst
eV
.
Licence information
Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP3.
Attribution 3.0 United States