  In hidden sector models with an extra U(1) gauge group, new fields can
interact with the Standard Model only through gauge kinetic mixing and the
Higgs portal. After the U(1) is spontaneously broken, these interactions couple
the resultant cosmic strings to Standard Model particles. We calculate the
spectrum of radiation emitted by these "dark strings" in the form of Higgs
bosons, Z bosons, and Standard Model fermions assuming that string tension is
above the TeV scale. We also calculate the scattering cross sections of
Standard Model fermions on dark strings due to the Aharonov-Bohm interaction.
These radiation and scattering calculations will be applied in a subsequent
paper to study the cosmological evolution and observational signatures of dark
strings.
