There are, altogether, five distinct CP conserving 
modes,
which are listed in Tab. 1 together with their branching ratios and the
corresponding number of `tagged' events obtainable at DA
NE, with a
luminosity of 
in a detector with 
angular coverage such as KLOE. If, for some channel, `tagging' is not
needed, the corresponding number of events might be larger. The numbers
in Tab. 1 are taken from PDG [1], except that (i) the branching
ratio of 
is the most recent determination with the NA31
detector [2], which is three times more precise than
previous experiments, and (ii) for the rare decay
, which has not been directly observed yet, the
upper and lower entries are, respectively, the results obtained by the
FNAL E621 [3] and the CPLEAR [4] collaborations, by studying
the time-dependence of 
-
interference. The number of
decays expected at DA
NE is the one
implied by the isospin analysis of 
and 
experimental data (assuming 
), which indicates
the branching ratio 
for this
channel [5].
Table 1: Experimental 
branching ratios.