  We calculate the cumulants of the charge transmitted through a chaotic cavity
in the limit that the two openings have a large number of scattering channels.
The shot noise, which is the second cumulant, is known to be insensitive to
dephasing in this limit. Unexpectedly, the fourth and higher cumulants are
found to depend on dephasing: A semiclassical theory and a quantum mechanical
model with strong dephasing give a different result than a fully phase-coherent
quantum mechanical theory.
