Spontaneous CP nonconservation and natural flavor conservation: A minimal model

Branco, G. C.

doi:10.1016/b978-0-444-88081-9.50026-6

Cited by 21 publications

(48 citation statements)

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“…It is obvious that for θ = 0, π the vacuum is CP invariant. It has also been shown [13] that for θ = π/2 the vacuum is also CP invariant. Note from eq.…”

Section: Minimizationmentioning

confidence: 88%

Vacuum induced CP violation generating a complex CKM matrix with controlled scalar FCNC

Nebot¹,

Botella

Branco³

2019

Eur. Phys. J. C

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We propose a viable minimal model with spontaneous CP violation in the framework of a Two Higgs Doublet Model. The model is based on a generalised Branco-Grimus-Lavoura model with a flavoured Z 2 symmetry, under which two of the quark families are even and the third one is odd. The lagrangian respects CP invariance, but the vacuum has a CP violating phase, which is able to generate a complex CKM matrix, with the rephasing invariant strength of CP violation compatible with experiment. The question of scalar mediated flavour changing neutral couplings is carefully studied. In particular we point out a deep connection between the generation of a complex CKM matrix from a vacuum phase and the appearance of scalar FCNC. The scalar sector is presented in detail, showing that the new scalars are necessarily lighter than 1 TeV. A complete analysis of the model including the most relevant constraints is performed, showing that it is viable and that it has definite implications for the observation of New Physics signals in, for example, flavour changing Higgs decays or the discovery of the new scalars at the LHC. We give special emphasis to processes like t → hc, hu, as well as h → bs, bd, which are relevant for the LHC and the ILC.

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“…It is obvious that for θ = 0, π the vacuum is CP invariant. It has also been shown [13] that for θ = π/2 the vacuum is also CP invariant. Note from eq.…”

Section: Minimizationmentioning

confidence: 88%

Vacuum induced CP violation generating a complex CKM matrix with controlled scalar FCNC

Nebot¹,

Botella

Branco³

2019

Eur. Phys. J. C

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“…The values of m 2 11 and m 2 22 are determined by the minimization conditions for a minimum of the vacuum once tan β is determined. To avoid tree level flavour-changing neutral currents (FCNC), the discrete Z 2 symmetry (Φ 1 → Φ 1 and Φ 2 → −Φ 2 ) is imposed [14][15][16], and as a result, the parameters λ 6 and λ 7 are set to zero. Allowing a non-zero value for the parameter m 2 12 , the Z 2 symmetry is softly broken though.…”

Section: Two-higgs-doublet Modelmentioning

confidence: 99%

Capability of future linear colliders to discover heavy neutral CP-even and CP-odd Higgs bosons within type-I 2HDM

Hashemi¹,

Haghighat²

2018

J. Phys. G: Nucl. Part. Phys.

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In this study, assuming the type-I 2HDM at SM-like scenario, observability of heavy neutral CP-even and CP-odd Higgs bosons H and A at a linear collider operating at √ s = 1 TeV is investigated through the signal process chain e − e + → AH → ZHH where the Z boson experiences a leptonic (e − e + or µ − µ + ) decay and the H Higgs boson is assumed to decay into a di-photon. This signal process is motivated especially by the clean signature which leptonic and photonic events can provide at colliders, and also by the enhancement due to the charged Higgs-mediated contribution to H di-photon decay at large tan β values. Simulation is based on four benchmark points according to which the Higgs mass m H (m A ) varies within the range 150-300 (200-400) GeV. Energy smearing of jets and photons are performed, and momentum smearing is also applied to leptons. Results indicate that, for all of the assumed benchmark points, the Higgs bosons H and A are observable with measurable masses, and with signals exceeding 5σ at integrated luminosities 111 and 201 f b −1 respectively. Such luminosities are easily accessible to future linear colliders.

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“…As mentioned above, CP can be spontaneously violated in models with three Higgs doublets with Z 2 symmetries [10]. Such is also the case for an S 3 symmetry [34,35,36].…”

mentioning

confidence: 90%

“…Discrete symmetries play an important role in reducing this number and lead at the same time to testable predictions. Symmetries also play an important role in stabilising dark matter [31,32,33].As mentioned above, CP can be spontaneously violated in models with three Higgs doublets with Z 2 symmetries [10]. Such is also the case for an S 3 symmetry [34,35,36].This talk is based on the work done in Ref.…”

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confidence: 97%

Spontaneous symmetry breaking in three-Higgs-doubletS₃-symmetric models

Emmanuel-Costa

Ogreid

Osland

et al. 2017

J. Phys.: Conf. Ser.

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The talk summarises work done by the authors consisting of a detailed study of the possible vacua in models with three Higgs doublets with S3 symmetry and without explicit CP violation. Different vacua require special regions of the parameter space which were analysed in our work. We establish the possibility of spontaneous CP violation in this framework and we also show which complex vacua conserve CP. In our work we discussed constraints from vacuum stability. The results presented here are relevant for model building.5 Affiliation valid till the end of 2016 with two Higgs doublets and NFC, with the Z 2 symmetry softly broken in the Higgs potential [8]. Three Higgs doublets and NFC with exact Z 2 symmetries allow for CP to be violated either explicitly [9] or spontaneously [10]. FCNC can also be eliminated at tree level assuming alignment of Yukawa couplings in flavour space [11], in this case complex Yukawa couplings give rise to new sources of CP violation. There have been several attempts at obtaining Yukawa alignment in several extensions of the SM [12,13,14,15]. Another very interesting possibility to avoid the problem of having too large FCNC with two Higgs doublets, is to build models allowing for Higgs mediated FCNC which are under control by means of a symmetry that leads to couplings suppressed by small off-diagonal elements of the quark mixing matrix V CKM . The first models of this type, based on a symmetry, were proposed by Branco, Grimus and Lavoura (BGL) [16]. Implications of BGL-type models have been extensively analysed recently, in the light of the LHC results, for several different implementations [17,18,19,20,21,22]. BGL-type models can have FCNC either in the up sector or in the down sector but not in both sectors at the same time. Recently, a generalisation of BGL-type models allowing for FCNC in both sectors was built [23]. BGL models models can also be extended to the case of three doublets [17].Three-Higgs-doublet models may provide good dark matter candidates [24,25,26,27,28,29]. One may also speculate that nature is such that three generations of fermions come with three Higgs doublets, which is, of course, an issue to be settled by experiment. As the number of doublets increases so does the complexity of the scalar potential and the number of free parameters in the theory [30]. Discrete symmetries play an important role in reducing this number and lead at the same time to testable predictions. Symmetries also play an important role in stabilising dark matter [31,32,33].As mentioned above, CP can be spontaneously violated in models with three Higgs doublets with Z 2 symmetries [10]. Such is also the case for an S 3 symmetry [34,35,36].This talk is based on the work done in Ref. [35] where the possible vacuum solutions were analysed and the possibility of having spontaneous CP violation in the context of three Higgs doublets, with an S 3 symmetry, was studied. In this work we concentrated our attention on the scalar potential. Several authors have considered implications of three-Higgs...

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Spontaneous CP nonconservation and natural flavor conservation: A minimal model

Cited by 21 publications

References 0 publications

Vacuum induced CP violation generating a complex CKM matrix with controlled scalar FCNC

Vacuum induced CP violation generating a complex CKM matrix with controlled scalar FCNC

Capability of future linear colliders to discover heavy neutral CP-even and CP-odd Higgs bosons within type-I 2HDM

Spontaneous symmetry breaking in three-Higgs-doubletS₃-symmetric models

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Spontaneous CP nonconservation and natural flavor conservation: A minimal model

Cited by 21 publications

References 0 publications

Vacuum induced CP violation generating a complex CKM matrix with controlled scalar FCNC

Vacuum induced CP violation generating a complex CKM matrix with controlled scalar FCNC

Capability of future linear colliders to discover heavy neutral CP-even and CP-odd Higgs bosons within type-I 2HDM

Spontaneous symmetry breaking in three-Higgs-doubletS3-symmetric models

Contact Info

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Resources

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Spontaneous symmetry breaking in three-Higgs-doubletS₃-symmetric models