The scattering of a nucleon beam on a non-Abelian flux line (proposed by Wu and Yang for testing the existence of gauge fields) is studied in a test-particle framework. All predictions of Wu and Yang are quantitatively confirmed. In particular, protons can be turned into neutrons under suitable conditions. (Charge conservation is restored at the field-theoretical level.) Similar results hold for the scattering of π mesons. A ‘‘shadow’’ of the effect survives also in the classical limit.

• Received 15 May 1985

DOI:https://doi.org/10.1103/PhysRevD.33.407