Neutral Kaons can decay into 
and 
final
states. For the decay mode, the 
pair can
have total isospin I'=0,1 and 2. The total wave function has
to be symmetric under exchange of 
and 
. If the
orbital angular momentum of the state is odd then
the isospin must be I'=1 and I'=0,2 for even angular momentum.
The total isospin must be I=3,2,1 or 0.
The decay rates of the 
and 
state into the 
final state can
be expressed as:
with the usual Dalitz parameters:
The energies 
are defined in the rest frame of the neutral kaon.
The 
violating contribution to the decay is
suppressed due to the centrifugal barrier and neglected in 
.
The conserving contributions to the decay proportional to
X vanish in the case of the final state because X is antisymmetric
with respect to the exchange of 
and 
.
The total decay rates of 
and 
are given by integrating over the
whole phase space:
In this case 
becomes zero if there is no violation
in decays whereas 
in addition to the violating
amplitude contains also the conserving amplitude for the
final state.
In the limit of small 
and 
violation we get
and
.
The interference term can be extracted using the following time dependent
decay rate asymmetry:
where 
.
Even with the contribution of the conserving amplitude in the
decay we can write the asymmetry to a good approximation as:
