When quarks and leptons propagate in the background of a grand unified cosmic string, various baryon number violating processes can occur. We argue that, because of the long-range pure gauge field that surrounds the string, the cross sections for these processes are generically enhanced by large factors over the naive, geometric, cross section. We explicitly calculate the cross section for quark to lepton transitions in a simplified model and find that it is enhanced by a factor of up to (Λ/Mproton)2 where Λ is the grand unification scale. In an appendix we discuss the possible boundary conditions for the fermionic wave functions, and calculate the correct choice of boundary condition for our model system.
ASJC Scopus subject areas
- Nuclear and High Energy Physics