SO(10) Cosmic Strings and Baryon Number Violation
  SO(10) cosmic strings formed during the phase transition Spin(10) $\rightarrow$ SU(5) $\times{\cal Z}_2$ are studied. Two types of strings --- one effectively Abelian and one non-Abelian --- are constructed and the string solutions are calculated numerically. The non-Abelian string can catalyze baryon number violation via the ``twisting'' of the scalar field which causes mixing of leptons and quarks in the fermion multiplet. The non-Abelian string is also found to have the lower energy possibly for the entire range of the parameters in the theory. Scattering of fermions in the fields of the strings is analyzed, and the baryon number violation cross section is calculated. The role of the self-adjoint parameters is discussed and the values are computed. 
Chung-Pei Ma