UV descriptions of composite Higgs models without elementary scalars

Abstract

We consider four-dimensional UV descriptions of composite Higgs models without elementary scalars, in which four-fermion interactions are introduced to an underlying gauge theory like in the gauged NJL model. When the anomalous dimension of the fermion bilinear is large, these interactions drive the spontaneous global symmetry breaking in the model, with the Higgs identified as a Nambu-Goldstone boson. The UV descriptions support composite top partner operators, also with large anomalous dimensions, thereby providing an explicit realisation of the idea of partial compositeness. In particular, the composite SO(6)/SO(5) model can be described by an Sp gauge theory with four flavours of fermion, together with a vector-like pair of fermions transforming in the antisymmetric representation and charged under SU(3) colour. These fermions confine to produce both the Higgs and top partner bound states. Our methods can also be applied to different coset groups, suggesting that four-fermion operators can describe the underlying UV dynamics of other composite Higgs models.

Fundamental partial compositeness

“…In fact, by construction the new composite techni-baryons have mass dimensions close to the minimum required of 5/2. Because any purely fermionic extension [27][28][29][30] is required to have composite baryons with dimensions close to 5/2, these baryons would presumably behave as if they were made by a fermion and a composite scalar similar to ours (see also [31] for a supersymmetric realization). The technicolor group is indicated by G TC , which can be either SU(N ), SO(N ) or Sp(N ) with vectorial techni-fermions and techni-scalars.…”

Gauge theories of partial compositeness: scenarios for Run-II of the LHC

“…The recent model building activities try to combine the two. Few explicit proposals have been made so far: [11,12] and [13] and a partial classification of the available options was made in [14]. (For earlier attempts using supersymmetry, see [15,16].…”

Symmetry restoration at high-temperature in two-color and two-flavor lattice gauge theories

“…The model has received some attention in a third context [14][15][16][17][18][19][20][21][22][23][24][25][26][27], as a concrete realization of the idea of Higgs compositeness [28]. This is a quite distinct framework in respect to traditional TC.…”

“…where the summations over flavor index i = 1, 2 and color index a = 1, 2 are understood, and where the field-strength tensors are defined in terms of the gauge bosons as We collect in appendix A and B several useful relations between 2-component spinors q and 4-component spinors Q, as well as details about the algebra of SU(4) and Sp(4) (see also [14][15][16][17][18][19][20][21][22][23][24][25][26][27]). The global symmetry acting on the matter fields is U(1) A × SU(4), and we explicitly list the transformation properties of the fields in table 1.…”