  The production and decay of the X(3872) are analyzed under the assumption
that the X is a weakly-bound molecule of the charm mesons D^0 \bar D^{*0} and
D^{*0} \bar D^0. The decays imply that the large D^0 \bar D^{*0} scattering
length has an imaginary part. An effective field theory for particles with a
large complex scattering length is used to derive factorization formulas for
production rates and decay rates of X. If a partial width is calculated in a
model with a particular value of the binding energy, the factorization formula
can be used to extrapolate to other values of the binding energy and to take
into account the width of the X. The factorization formulas relate the rates
for production of X to those for production of D^0 \bar D^{*0} and D^{*0} \bar
D^0 near threshold. They also imply that the line shape of X differs
significantly from that of a Breit-Wigner resonance.
