Holographic Twin Higgs Model

122

184

We explore a simple solution to the cosmological challenges of the original Mirror Twin Higgs (MTH) model that leads to interesting implications for experiment. We consider theories in which both the standard model and mirror neutrinos acquire masses through the familiar seesaw mechanism, but with a low right-handed neutrino mass scale of order a few GeV. In these νMTH models, the right-handed neutrinos leave the thermal bath while still relativistic. As the universe expands, these particles eventually become nonrelativistic, and come to dominate the energy density of the universe before decaying. Decays to standard model states are preferred, with the result that the visible sector is left at a higher temperature than the twin sector. Consequently the contribution of the twin sector to the radiation density in the early universe is suppressed, allowing the current bounds on this scenario to be satisfied. However, the energy density in twin radiation remains large enough to be discovered in future cosmic microwave background experiments. In addition, the twin neutrinos are significantly heavier than their standard model counterparts, resulting in a sizable contribution to the overall mass density in neutrinos that can be detected in upcoming experiments designed to probe the large scale structure of the universe.

Section: Jhep07(2017)023mentioning

confidence: 99%

Cosmology in Mirror Twin Higgs and neutrino masses

Chacko

Craig

Fox

et al. 2017

122

184

“…They are related to the SM fermions and bosons by a discrete Z 2 symmetry which, together with the spontaneous breaking of a global symmetry that turns the Higgs into a pseudo Nambu-Goldstone boson (pNGB), guarantees that the Higgs mass be insensitive to the UV contributions. The resulting possibility of having a natural EWSB with the absence of detectable new physics at the LHC has sparked interest in this class of models in the last years, [6][7][8][9][10][11][12][13][14][15][16][17], but many questions still remain open. In particular, an important problem is to analyze the capability of this scenario to reproduce the observed value of M H , irrespective of any possible UV completion, supersymmetric or composite, of the low-energy Lagrangian.…”

Section: Jhep11(2016)108mentioning

confidence: 99%

The RG-improved Twin Higgs effective potential at NNLL

Greco¹,

Mimouni²

2016

We present the Renormalization Group improvement of the Twin Higgs effective potential at cubic order in logarithmic accuracy. We first introduce a modelindependent low-energy effective Lagrangian that captures both the pseudo-Nambu-Goldstone boson nature of the Higgs field and the twin light degrees of freedom charged under a copy of the Standard Model. We then apply the background field method to systematically re-sum all the one loop diagrams contributing to the potential. We show how this technique can be efficient to implicitly renormalize the higher-dimensional operators in the twin sector without classifying all of them. A prediction for the Higgs mass in the Twin Higgs model is derived and found to be of the order of M H ∼ 120 GeV with an ultraviolet cut-off m * ∼ 10-20 TeV. Irrespective of any possible ultraviolet completion of the lowenergy Lagrangian, the infrared degrees of freedom alone are therefore enough to account for the observed value of the Higgs mass through running effects.

“…Energy transferred through annihilations may be similarly calculated as 6) where dσ jj→iī dΩ is now the differential annihilation cross section. This rate may be evaluated as described above and is more directly amenable to the factorisation of the integrals observed in [23].…”

Section: Jhep05(2017)038mentioning

confidence: 99%

“…While these constraints could be avoided if the two sectors were at radically different temperatures, the Higgs portal couplings required by naturalness keep the two sectors in thermal equilibrium down to relatively low temperatures. Constraints on dark radiation in the mirror Twin Higgs have motivated models in which the Z 2 symmetry is approximate (such as the orbifold [4,5], holographic [6][7][8], fraternal [9], and vector-like [10] Twin Higgs), in which case the dark radiation component can be made naturally small. This problem was examined recently in [11], where the Z 2 symmetry in the fermion Yukawa couplings was broken in order to find an arrangement that would reduce the residual dark radiation from the twin particles.…”

Section: Jhep05(2017)038mentioning

confidence: 99%

Cosmological signals of a mirror twin Higgs

Craig

Koren

Trott

2017

138

Abstract:We investigate the cosmology of the minimal model of neutral naturalness, the mirror Twin Higgs. The softly-broken mirror symmetry relating the Standard Model to its twin counterpart leads to significant dark radiation in tension with BBN and CMB observations. We quantify this tension and illustrate how it can be mitigated in several simple scenarios that alter the relative energy densities of the two sectors while respecting the softly-broken mirror symmetry. In particular, we consider both the out-of-equilibrium decay of a new scalar as well as reheating in a toy model of twinned inflation, Twinflation. In both cases the dilution of energy density in the twin sector does not merely reconcile the existence of a mirror Twin Higgs with cosmological constraints, but predicts contributions to cosmological observables that may be probed in current and future CMB experiments. This raises the prospect of discovering evidence of neutral naturalness through cosmology rather than colliders.