Exploring holographic Composite Higgs models

Abstract

Simple Composite Higgs models predict new vector-like fermions not too far from the electroweak scale, yet LHC limits are now sensitive to the TeV scale. Motivated by this tension, we explore the holographic dual of the minimal model, MCHM 5 , to try and alleviate this tension without increasing the fine-tuning in the Higgs potential. Interestingly, we find that lowering the UV cutoff in the 5D picture allows for heavier top partners and less fine-tuning. In the 4D dual this corresponds to increasing the number of "colours" N , thus increasing the decay constant of the Goldstone Higgs. This is essentially a 'Little Randall-Sundrum Model', which are known to reduce some flavour and electroweak constraints. Furthermore, in anticipation of the ongoing efforts at the LHC to put bounds on the top Yukawa, we demonstrate that deviations from the SM can be suppressed or enhanced with respect to what is expected from mere symmetry arguments in 4D. We conclude that the 5D holographic realisation of the MCHM 5 with a small UV cutoff is not in tension with the current experimental data.

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

“…We leave instead a detailed phenomenological analysis for future work. For recent phenomenological work in the area a surely incomplete list is [20][21][22][23][24][25].…”

Flavor hierarchies from dynamical scales

“…It is also possible to reduce some bounds by taking smaller g * , but this implies reducing the UV cutoff (see for example ref. [19]). …”

Dilaton portal in strongly interacting twin Higgs models

“…Neglecting the radion field for now, we write down the effective Lagrangians for the interactions between the Higgs, top sector, and gauge fields in the holographic SITH model: and M t,t 1 are calculated using 5D holographic techniques and can be found in [26,62]. The form factors contain poles at the masses of the heavy composite/KK states, however in studying the phenomenology below the TeV scale we need only to look at the low energy behavior of these form factors to extract the couplings to the Higgs boson and the radion.…”