AbstractNew measurements on cross sections in $$e^+e^-\rightarrow J/\psi \pi ^+\pi ^-$$
e
+
e
-
→
J
/
ψ
π
+
π
-
, $$h_c\pi ^+\pi ^-$$
h
c
π
+
π
-
, $$D^0D^{*-}\pi ^++c.c.$$
D
0
D
∗
-
π
+
+
c
.
c
.
, $$\psi (2S)\pi ^+\pi ^-$$
ψ
(
2
S
)
π
+
π
-
, $$\omega \chi _{c0}$$
ω
χ
c
0
and $$J/\psi \eta $$
J
/
ψ
η
channels have been carried out by BESIII, Belle and BABAR experiments, as well as in the $$D_s^{*+}D_s^{*-}$$
D
s
∗
+
D
s
∗
-
channel. We perform extensive numerical analyses by combining all these data available, together with those in $$D^+D^{*-}+c.c.$$
D
+
D
∗
-
+
c
.
c
.
and $$D^{*+}D^{*-}$$
D
∗
+
D
∗
-
channels. Though the latter show no evident peak around $$\sqrt{s}=4.230$$
s
=
4.230
GeV, the missing X(4260) is explained as that it is concealed by the interference effects of the well established charmonia $$\psi (4040)$$
ψ
(
4040
)
, $$\psi (4160)$$
ψ
(
4160
)
and $$\psi (4415)$$
ψ
(
4415
)
. Our analyses reveal that the leptonic decay width of X(4260) ranges from $$\mathcal {O}(10^2)$$
O
(
10
2
)
eV to $$\mathcal {O}(1)$$
O
(
1
)
keV, and hence it is probably explained in the conventional quark model picture. That is, the X(4260) may well be interpreted as a mixture of $$4^3S_1$$
4
3
S
1
and $$3^3D_1$$
3
3
D
1
($$2^3D_1$$
2
3
D
1
) states.
Dynamical relativistic corrections to the leptonic decay width of heavy quarkonia