Criticality in the scale invariant standard model (squared)

Autor: Robert Foot, Archil Kobakhidze, Alexander Spencer-Smith
Jazyk: angličtina
Rok vydání: 2015
Předmět:
Zdroj: Physics Letters B, Vol 747, Iss C, Pp 169-172 (2015)
Druh dokumentu: article
ISSN: 0370-2693
1873-2445
DOI: 10.1016/j.physletb.2015.05.064
Popis: We consider first the standard model Lagrangian with μh2 Higgs potential term set to zero. We point out that this classically scale invariant theory potentially exhibits radiative electroweak/scale symmetry breaking with very high vacuum expectation value (VEV) for the Higgs field, 〈ϕ〉≈1017–18 GeV. Furthermore, if such a vacuum were realized then cancellation of vacuum energy automatically implies that this nontrivial vacuum is degenerate with the trivial unbroken vacuum. Such a theory would therefore be critical with the Higgs self-coupling and its beta function nearly vanishing at the symmetry breaking minimum, λ(μ=〈ϕ〉)≈βλ(μ=〈ϕ〉)≈0. A phenomenologically viable model that predicts this criticality property arises if we consider two copies of the standard model Lagrangian, with exact Z2 symmetry swapping each ordinary particle with a partner. The spontaneously broken vacuum can then arise where one sector gains the high scale VEV, while the other gains the electroweak scale VEV. The low scale VEV is perturbed away from zero due to a Higgs portal coupling, or via the usual small Higgs mass terms μh2, which softly break the scale invariance. In either case, the cancellation of vacuum energy requires Mt=(171.53±0.42) GeV, which is close to its measured value of (173.34±0.76) GeV.
Databáze: Directory of Open Access Journals
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