Violation of the Appelquist-Carazzone decoupling in non-SUSY GUT
arXiv:0707.2323 · doi:10.1103/PhysRevD.77.025033
Abstract
We point out that in non supersymmetric GUTs, in which the SU(5) gauge symmetry is broken down to the Standard Model gauge group by a Higgs multiplet the Appelquist-Carazzone decoupling is violated. This is because the Higgs triplet contained in the acquires a dimensionfull coupling to the Higgs doublets which is proportional to the GUT breaking vacuum expectation value (VEV) . As a result, at one loop heavy gauge and Higgs fields contribution to tadpoles generate a VEV of the triplet which is not suppressed for and violates the custodial symmetry.
17 pages, no figures