Neutron electric dipole moment in the gauge-Higgs unification

We address the challenging issue of how CP violation is realized in higher dimensional gauge theories without higher dimensional elementary scalar fields. In such theories interactions are basically governed by a gauge principle and therefore to get CP violating phases is a non-trivial task. It is demonstrated that CP violation is achieved as the result of compactification of extra dimensions, which is incompatible with the 4-dimensional CP transformation. As a simple example we adopt a 6-dimensional U(1) model compactified on a 2-dimensional orbifold T 2 /Z 4 . We argue that the 4-dimensional CP transformation is related to the complex structure of the extra space and show how the Z 4 orbifolding leads to CP violation. We confirm by explicit calculation of the interaction vertices that CP violating phases remain even after the re-phasing of relevant fields. For completeness, we derive a re-phasing invariant CP violating quantity, following a similar argument in the Kobayashi-Maskawa model which led to the Jarlskog parameter. As an example of a CP violating observable we briefly comment on the electric dipole moment of the electron.

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“…The general formulas for these two types of diagrams are known to be proportional to 2iIm(ab * ) and 2iIm(a ′ b ′ * ), respectively [6].…”

Section: Re-phasing Invariant Quantitiesmentioning

confidence: 99%

“…Another possibility of spontaneous CP violation in this type of theory is due to the vacuum expectation value of an effective four-dimensional scalar field, which is originally the extra space component of the gauge field and may have an odd CP eigenvalue [5,6].…”

Section: Introductionmentioning

confidence: 99%

CPviolation due to compactification

2010

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“…An essential property of the GHU scenario is that the SM Higgs doublet is identified with an extra spatial component of the gauge field in higher dimensions. Associated with the higher-dimensional gauge symmetry, the GHU scenario predicts various finite physical observables, irrespective of the non-renormalizability of the scenario, such as the effective Higgs potential [7][8][9][10][11][12], the effective Higgs coupling with digluon/diphoton [13][14][15], the anomalous magnetic moment g − 2 [16,17], and the electric dipole moment [18].…”

Section: Introductionmentioning

confidence: 99%

Fermion dark matter in gauge-Higgs unification

Maru

Miyaji

Okada

et al. 2017

J. High Energ. Phys.

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We propose a Majorana fermion dark matter in the context of a simple gaugeHiggs Unification (GHU) scenario based on the gauge group SU(3)×U(1) ′ in 5-dimensional Minkowski space with a compactification of the 5th dimension on S 1 /Z 2 orbifold. The dark matter particle is identified with the lightest mode in SU(3) triplet fermions additionally introduced in the 5-dimensional bulk. We find an allowed parameter region for the dark matter mass around a half of the Standard Model Higgs boson mass, which is consistent with the observed dark matter density and the constraint from the LUX 2016 result for the direct dark matter search. The entire allowed region will be covered by, for example, the LUX-ZEPLIN dark matter experiment in the near future. We also show that in the presence of the bulk SU(3) triplet fermions the 125 GeV Higgs boson mass is reproduced through the renormalization group evolution of Higgs quartic coupling with the compactification scale of around 10 8 GeV.

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“…Works on the oblique electroweak parameters and fermion anomalous magnetic moment from such a viewpoint have been already done in the literature [6][7][8]. The second issue has been addressed in our previous papers [9,10], where CP violation is claimed to be achieved spontaneously either by the VEV of the Higgs field or by the complex structure of the compactified extra space.…”

Section: Introductionmentioning

confidence: 95%