Higgs as a holographic pseudo-Goldstone boson

Abstract

The AdS/CFT correspondence allows one to relate 4D strongly coupled theories to weakly coupled theories in 5D AdS. We use this correspondence to study a scenario in which the Higgs appears as a composite pseudo-Goldstone boson (PGB) of a strongly coupled theory. We show how a nonlinearly realized global symmetry protects the Higgs mass and guarantees the absence of quadratic divergences at any loop order. The gauge and Yukawa interactions for the PGB Higgs are simple to introduce in the 5D AdS theory, and their one-loop contributions to the Higgs potential are calculated using perturbation theory. These contributions are finite, giving a squared-mass to the Higgs which is one-loop smaller than the mass of the first Kaluza-Klein state. We also show that if the symmetry breaking is caused by boundary conditions in the extra dimension, the PGB Higgs corresponds to the fifth component of the bulk gauge boson. To make the model fully realistic, a tree-level Higgs quartic coupling must be induced. We present a possible mechanism to generate it and discuss the conditions under which an unwanted large Higgs mass term is avoided. (C) 2003 Elsevier B.V. All rights reserved

Randall–Sundrum reality at the LHC

“…In order to suppress unwanted higher dimensional operators, which are not sufficiently suppressed by the TeV-scale cutoff on the IR brane in the RS1 model, SM gauge fields [2,3,4,5] and fermions [6,7] are considered to propagate in the bulk space. In this new setup [2,3,4,5,6,7,8,9,10,11,12,13,14,15,16], denoted as the RS model, RS can address both the hierarchy problem and fermion mass hierarchies. From the electroweak precision measurements and various flavor physics, the new Kaluza-Klein (KK) modes of the bulk SM fields are constrained to be heavier than a few TeV [2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23].…”

Light non-degenerate composite partners at the LHC

“…In this paper we transpose the logic of ref. [20] and item (i) above in the context of minimal CHMs where the Higgs doublet is realized as a pseudo-Nambu-Goldstone-boson (pNGB) [21][22][23][24][25][26][27][28][29] (see also [30]). In particular we address the question of how light can the first and second generation quark partners be without assuming degenerate compositeness parameters.…”

How well do we need to measure Higgs boson couplings?

“…Explicit models realizing this are Little Higgs models [16] and Holographic composite Higgs models [17,18]. An effective field theory for such a strongly interacting light Higgs (SILH) boson has been developed in Ref.…”