Λ
c
Λ
c
Λ
c
Λ
c
and charm-anticharm
are the creation of
2
quark-antiquark pairs
away from each other.
D*D* and charm-anticharm
are the creation of
only
1
quark-antiquark pair
away from each other.
Left:
&psi (5S)
and
&psi (4D)
couple
weakly
to
Λ
c
Λ
c
.
Right:
Λ
c
Λ
c
couples
weakly
to
c
c
arXiv:1004.4368