Two-loop calculation of Higgs mass in gauge-Higgs unification:: 5D massless QED compactified on S1

We calculate the quantum corrections to the mass of the zero mode of the fifth component of the gauge field at two-loop level in a five-dimensional massless QED compactified on S-1. We discuss in detail how the divergences are exactly canceled and the mass becomes finite. The key ingredients to obtain the result are the shift symmetry and the Ward-Takahashi identity. We also evaluate the finite part of corrections. (c) 2006 Elsevier B.V. All rights reserved.