Related papers: Precision Tests and Fine Tuning in Twin Higgs Mode…
Twin Higgs models solve the little hierarchy problem without introducing new colored particles, however they are often in tension with measurements of the radiation density at late times. Here we explore viable cosmological histories for…
Constraints from precision electroweak measurements reveal no evidence for new physics up to 5 - 7 TeV, whereas naturalness requires new particles at around 1 TeV to address the stability of the electroweak scale. We show that this "little…
Supersymmetric unified models in which the Z' couples to the Higgs doublets, as in the E6 class of models, have large fine tuning dominated by the experimental mass limit on the Z'. To illustrate this we investigate the degree of fine…
Models of Gauge-Higgs unification in extra dimensions offer a very elegant playground where one can study electroweak symmetry breaking. The nicest feature is that gauge symmetry itself protects the Higgs potential from divergences, thus…
We study the predictions of generic ultraviolet completions of two-Higgs doublet models. We assume that at the matching scale between the two-Higgs doublet model and a ultraviolet complete theory -- which can be anywhere between the TeV and…
We perform an analysis of the electroweak precision observables in the Lee-Wick Standard Model. The most stringent restrictions come from the S and T parameters that receive important tree level and one loop contributions. In general the…
We reexamine the strength of the first order phase transition in the electroweak theory supplemented by an extra Higgs doublet. The finite-temperature effective potential, $V_{eff}$, is computed to one-loop order, including the summation of…
We show that if the Standard Model gauge fields and fermions propagate in extra dimenions, a composite Higgs field with the correct quantum number can arise naturally as a bound state due to the strong gauge interactions in higher…
We perform the fit of electroweak precision observables within the Standard Model with a 126 GeV Higgs boson, compare the results with the theoretical predictions and discuss the impact of recent experimental and theoretical improvements.…
In composite Higgs models (CHMs), electroweak precision data generically push colourless composite vector resonances to a regime where they dominantly decay into pairs of light top partners. This greatly attenuates their traces in canonical…
The quadratic divergences of the Higgs mass may be cancelled either accidentally or by the exchange of some new particles. Alternatively its impact on naturalness may be weakened by raising the Higgs mass, which requires changing the…
We study analytically and numerically the bounds imposed by the electroweak precision tests on a minimal composite Higgs model. The model is based on spontaneous SO(5)/SO(4) breaking, so that an approximate custodial symmetry is preserved.…
In a recent paper, we introduced a new Little Higgs model, which contains the gauge structure $SU(2)^3\times U(1)$, embedded in an approximate global $SO(5)\times SO(5)$ symmetry. After breaking to the standard model, $SU(2)_L \times…
We investigate grand unified theories (GUTs) in scenarios where electroweak (EW) symmetry breaking is triggered by a light composite Higgs, arising as a Nambu-Goldstone boson from a strongly interacting sector. The evolution of the standard…
Higgs precision program at future lepton collider aims at (sub) percent level precision measurement of the Higgs properties, shedding light to new physics through the Higgs lamppost. Amongst many exclusive Higgs channels that can be…
Radiative corrections with new heavy particles coupling to Higgs doublets destabilize the electroweak scale and require an ad-hoc counterterm cancelling the large loop contribution. If the mass scale m1 of these new particles in in the TeV…
We investigate the amount of fine tuning of the electroweak scale in the presence of new physics beyond the MSSM, parametrized by higher dimensional operators. We show that these significantly reduce the MSSM fine tuning to Delta<10 for a…
We study the correlation between the value of the triple Higgs coupling and the nature of the electroweak phase transition. We use an effective potential approach, including higher order, non-renormalizable terms coming from integrating out…
If supersymmetry is broken directly to the Standard Model at energies not very far from the unified scale, the Higgs boson mass lies in the range 128-141 GeV. The end points of this range are tightly determined. Theories with the Higgs…
We present an update of the global fit of the Standard Model electroweak sector to latest experimental results. We include new kinematic top quark and $W$ boson mass measurements from the LHC, a $\sin^2\theta^{\ell}_{\mathrm{eff}}$ result…