Living beyond the edge: Higgs inflation and vacuum metastability

Abstract

The measurements of the Higgs mass and top Yukawa coupling indicate that we live in a very special universe, at the edge of the absolute stability of the electroweak vacuum. If fully stable, the Standard Model (SM) can be extended all the way up to the inflationary scale and the Higgs field, nonminimally coupled to gravity with strength ξ, can be responsible for inflation. We show that the successful Higgs inflation scenario can also take place if the SM vacuum is not absolutely stable. This conclusion is based on two effects that were overlooked previously. The first one is associated with the effective renormalization of the SM couplings at the energy scale M P =ξ, where M P is the Planck scale. The second one is a symmetry restoration after inflation due to high temperature effects that leads to the (temporary) disappearance of the vacuum at Planck values of the Higgs field.

Triple Higgs boson production at a 100 TeV proton-proton collider

“…We collect these selection cuts in table 3. 6 We have verified explicitly that an alternative method based on minimization of the squared sum of (m bb − m h ) from each combination yields results that differ by O(1%) compared to the simpler ∆R method. 7 The distance between the other paired b-jets was not found to have significant discriminatory power.…”

“…The so-called 'self-couplings' and their energy dependence are crucial in determining the stability of the vacuum. Current observations suggest that our Universe may be sitting at a metastable false vacuum [1][2][3][4][5][6][7][8] and measurements of these couplings will illuminate this fact further. At colliders, these terms, i.e.…”

“…Here we consider, as an illustrative example, a simplified mode with the assumption that the effect of all coefficients apart from a single one, originating from an operator of the form O 6 ∼ |H| 6 , where H is the Higgs doublet scalar before electroweak symmetry breaking: Due to the relation appearing in eq. (1.3), the cross section for triple Higgs boson production is a quartic polynomial in c 6 , i.e.…”

“…As a simple choice, we take the highest-p T b-jet and pair it with the closest b-jet in ∆R = ∆η 2 + ∆φ 2 , and pair the other two remaining b-jets together. 6 We thus construct the paired b-jet invariant mass, respectively, m . 7 For the photon pair, we simply construct the invariant mass and impose a strong window on the measured Higgs boson mass m γγ ∈ [124, 126] GeV.…”

Higgs inflation as a mirage

“…leading to n ≃ 0.973 , r ≃ 0.0043 , 16) for N e ∼ 60. We see that the value of the scalar spectral index is somewhat larger than in the original scenario, but still in good agreement with the Planck values.…”