  A formula is derived that allows the computation of one-loop mass shifts for
self-dual semilocal topological solitons. These extended objects, which in
three spatial dimensions are called semi-local strings, arise in a generalized
Abelian Higgs model with a doublet of complex Higgs fields. Having a mixture of
global, SU(2), and local (gauge), U(1), symmetries, this weird system may seem
bizarre, but it is in fact the bosonic sector of electro-weak theory when the
weak mixing angle is of 90 degrees. The procedure for computing the
semi-classical mass shifts is based on canonical quantization and heat
kernel/zeta function regularization methods.
