  We describe the decay out of a superdeformed band using the methods of
reaction theory. Assuming that decay-out occurs due to equal coupling (on
average) to a sea of equivalent chaotic normally deformed (ND) states, we
calculate the average intraband decay intensity and show that it can be written
as an ``optical'' background term plus a fluctuation term, in total analogy
with average nuclear cross sections. We also calculate the variance in closed
form. We investigate how these objects are modified when the decay to the ND
states occurs via an ND doorway and the ND states' statistical properties are
changed from chaotic to regular. We show that the average decay intensity
depends on two dimensionless variables in the first case while in the second
case, four variables enter the picture.
