Constraints from triple gauge couplings on vectorlike leptons

We study spontaneous CP violation as a solution to the strong CP problem in left-right symmetric theories. The discrete CP symmetry is broken by a complex vacuum expectation value of a righthanded Higgs doublet. Heavy vectorlike down-type quarks mix with the Standard Model quarks introducing the known CP violation -realizing a variant of the Nelson-Barr mechanism. A nonvanishing QCD vacuum angle is generated at loop level. The implementation in the ultraviolet complete theory of trinification at low scales is discussed. We further comment on the phenomenology and future testability of the model.

“…Additionally, vectorlike leptons are a striking signature at future lepton colliders, projected limits can be found in Ref. [81].…”

Section: Phenomenology Of the Nelson-barr Mechanismmentioning

confidence: 94%

Spontaneous CP violation and the strong CP problem in left-right symmetric theories

Ohmer

2019

“…which can provide large enough Collider signatures of VLL are highly sensitive on the mixing with SM leptons [28][29][30][31][32][33][34]. The mass limit for charged leptons from the Large Electron-Positron collider (LEP) is 100.8 GeV when the charged lepton mostly decays to W ν.…”

Section: Vectorlike Leptonsmentioning

confidence: 99%

Spontaneous twin symmetry breaking

Jung

2019

We consider a twin Higgs model where the Z2 twin symmetry is broken spontaneously, not explicitly. We show that introducing an exact copy of the standard model with a renormalizable Higgs portal potential is enough to realize such a scenario. In this scenario, the SU (4) breaking scale f is determined by the scale where the Higgs self quartic coupling flips its sign, whose standard model prediction is O(10 10 GeV). For the misalignment of nonzero vacuum expectation values of the twin Higgs fields, it is explicitly shown that parameter tuning of O(m 2 h /f 2 ) is required, so we conclude that minimal setup does not solve the hierarchy problem. We point out that the tuning can be significantly reduced (f ∼ 2.7 TeV) if there are twin vectorlike leptons with a large Yukawa coupling.

“…However, the contribution of new the 2 This symmetry can be recognized as remnant symmetry at the end of the symmetry breaking chain of the SO(10) group to the SM [43]. 3 This particle setup has been also considered in studies associated to strengthening the electroweak phase transition [45], presicion test in future colliders [44,46,47], electroweak precision tests [48], generation of neutrino masses [49], fake split-supersymmetry [50], and UV completion of doublet fermion DM [51]. charged fermions to h → γγ generates a considerable suppression on the Higgs diphoton decay making such a scheme severely constrained by the interplay between the DM relic density constraint and the LHC measurement of the Higgs diphoton decay rate [38][39][40]49].…”

Section: Introductionmentioning

confidence: 99%

Phenomenology of doublet-triplet fermionic dark matter in nonstandard cosmology and multicomponent dark sectors

Betancur

Zapata

2018

We consider the doublet-triplet fermionic model in the scheme of the custodial limit when the dark matter (DM) candidate is pure doublet and lies at the electroweak scale. This scheme, despite being an appealing and promising DM model, is severely constrained by the interplay between the DM relic density constraint and the LHC measurement of the Higgs diphoton decay rate. In this work, the DM relic density is considered to arise from either a nonstandard cosmology scenario or as a part of a larger sector encompassing other DM particles, this in order to saturate the observed relic abundance. For these scenarios we investigate the impact of the new sector in different collider observables, and study constraints coming from direct detection and indirect detection of gamma-rays both in the diffuse and linelike spectrum. As a result, we find that in the nonstandard cosmology scenario most experiments impose, up to a certain point, restrictions, though large portions of the parameter space are still viable. For the multicomponent case, only direct detection imposes constraints.