Effects of bulk mass in gauge-Higgs unification

We study effects of bulk mass on electroweak symmetry breaking and Higgs mass in the scenario of five-dimensional SU(3) gauge-Higgs unification defined on M-4 x S-1/Z(2). The asymptotic form of effective potential for the Higgs field is obtained, from which a transparent and useful expression for the Higgs mass is found. The small vacuum expectation values (VEV) for Higgs field can be realized by choosing bulk mass parameters appropriately for a fixed set of matter content. The bulk mass for periodic fermion field, in general, has effects to make the Higgs mass less heavy. On the other hand, the bulk mass for antiperiodic field does not directly affect the Higgs mass, but it contributes to increase or decrease the Higgs mass, depending on how small the VEV is induced due to the antiperiodic field. We give numerical examples to confirm these effects, in which the role of the bulk mass is also definitely clear. (c) 2006 Elsevier B.V. All rights reserved.