In electron-positron annihilation
one produces dominantly vector mesons:
u
u
, d
d
, s
s
, c
c
and b
b
.
u
u
, d
d
and s
s
have very similar masses.
Hence, excitations are difficult to disentangle.
The next best bet is vector charmonium, c
c
.
Rather clean results may be expected.
