It is shown that generically cosmic strings will interact with matter via their pure gauge potential. The cross section is purely geometrical, and does not vanish in the limit of zero string size. The mechanism is the Aharonov-Bohm effect, which is already known to cause scattering of charged particles off an infinitesimally thin solenoid. A related mechanism for particle production is also discussed.

• Received 13 September 1988

DOI:https://doi.org/10.1103/PhysRevLett.62.1071