This field will most probably stay in the domain of fixed target experiments
since not enough energy is available in the decay of a B-meson
(the minimal decay chain would be
B 
).
The observation power is directly related to the total number of charm events
observable.
Baryon beams may have an advantage over 
or 
beams.
The use of a hyperon beam by E781 probably gives no advantage over the use of a
proton beam.
However,
the beam energy could be of importance (E781 has 600 GeV/c as compared to
280 GeV/c for COMPASS in its first stage).
Since COMPASS aims at 10 times higher statistics as compared to E781 and
the projected yields are of the order of 50-500 reconstructed events, it seems
unlikely that E781 could study these objects first.
Even if a first observation were done by E781
(which would imply a relatively high production cross section)
this would in turn imply
a richer physics program in this field for COMPASS.
In addition the COMPASS target detector should be better suited
to disentangle complex event topologies.