  Long-standing anomalies in K^+ nucleus integral cross sections could be
resolved by extending the impulse-approximation t*rho optical-potential
framework to incorporate K^+ absorption on pairs of nucleons. Substantially
improved fits to the data at p(lab)=500-700 MeV/c are obtained. An upper bound
of 3.5 mb for the absorption cross section of K^+ per nucleon is derived. We
conjecture that the underlying microscopic absorption process is K^+ n N -->
Theta^+ N, where Theta^+(1540) is the newly discovered exotic Y=2, I=0, Z=1
pentaquark baryon, and estimate that the cross section for K^+ d --> Theta^+ p
is a fraction of millibarn. Comments are made on Theta^+ production reactions
on nuclei.
