title: Traces of the theta+ pentaquark in K+ -nucleus dynamics.
abstract: Long-standing anomalies in K(+)-nucleus integral cross sections could be resolved by extending the impulse-approximation trho optical-potential framework to incorporate K(+) absorption on pairs of nucleons. Substantially improved fits to the data at p(lab) approximately 500-700 MeV/c are obtained. An upper bound on the absorption cross section per nucleon is derived, sigmaabs((K(+))/A approximately 3.5 mb. We conjecture that the underlying microscopic absorption process is K(+) nN--> Theta+ N, where Theta(+) (1540) is the newly discovered exotic Y = 2, I = 0, Z = 1 pentaquark baryon, and estimate that sigma(K(+) d--> Theta(+) p) is a fraction of millibarn. Comments are made on Theta(+) production reactions on nuclei.
authors.affiliation: Racah Institute of Physics, The Hebrew University, Jerusalem 91904, Israel.
authors.forename: A
authors.initials: A
authors.lastname: Gal
authors.forename: E
authors.initials: E
authors.lastname: Friedman