2018/03/21 by Lawrence J. Hall, Keisuke Harigaya
Physics and Astronomy · Social Sciences · #CP violation #Gauge boson #Gauge symmetry #Grand Unified Theory #Higgs boson #International Science and Diplomacy #Neutron electric dipole moment #Particle physics theoretical and experimental studies #Physics beyond the Standard Model #Proton decay #Quantum Chromodynamics and Particle Interactions #Quark #Standard Model (mathematical formulation) #hep-ph
paper · pdf · doi:10.1007/jhep10(2018)130
36 pages, 5 figures
arxiv created 2018/03/21 · openalex created_date 2018/03/29 · openalex publication_date 2018/10/01 · arxiv updated 2018/11/14 · openalex updated_date 2026/08/06
A bstract A Z 2 symmetry that extends the weak interaction, SU(2) L → SU(2) L ×SU(2) ′ , and the Higgs sector, H (2) → H (2 , 1) + H ′ (1 , 2), yields a Standard Model quartic coupling that vanishes at scale v ′ = 〈 H ′ 〉 ≫ 〈 H 〉. Near v ′ , theories either have a “prime” sector, or possess “Left-Right” (LR) symmetry with SU(2) ′ = SU(2) R . If the Z 2 symmetry incorporates spacetime parity, these theories can solve the strong CP problem. The LR theories have all quark and lepton masses arising from operators of dimension 5 or more, requiring Froggatt-Nielsen structures. Two-loop contributions to θ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mover> <mml:mi>θ</mml:mi> <mml:mo>¯</mml:mo> </mml:mover> </mml:math> are estimated and typically lead to a neutron electric dipole moment of order 10 −27 e cm that can be observed in future experiments. Minimal models, with gauge group SU(3) × SU(2) L × SU(2) L × U(1) B − L , have precise gauge coupling unification for v ′ = 10 10±1 GeV, successfully correlating gauge unification with the observed Higgs mass of 125 GeV. With SU(3) × U(1) B − L embedded in SU(4), the central value of the unification scale is reduced from 10 16−17 GeV to below 10 16 GeV, improving the likelihood of proton decay discovery. Unified theories based on SO(10) × CP are constructed that have H + H ′ in a 16 or 144 and generate higher-dimensional flavor operators, while maintaining perturbative gauge couplings.