Abstract
In a Mirror Twin World with a maximally symmetric Higgs sector the little hierarchy of the Standard Model can be significantly mitigated, perhaps displacing the cutoff scale above the LHC reach. We show that consistency with observations requires that the Z2 parity exchanging the Standard Model with its mirror be broken in the Yukawa couplings. A minimal such effective field theory, with this sole Z2 breaking, can generate the Z2 breaking in the Higgs sector necessary for the Twin Higgs mechanism. The theory has constrained and correlated signals in Higgs decays, direct Dark Matter Detection and Dark Radiation, all within reach of foreseen experiments, over a region of parameter space where the fine-tuning for the electroweak scale is 10-50%. For dark matter, both mirror neutrons and a variety of self-interacting mirror atoms are considered. Neutrino mass signals and the effects of a possible additional Z2 breaking from the vacuum expectation values of B-L breaking fields are also discussed.
Highlights
Mirror gauge interactions SU(3) × SU(2) × U(1)
In the appendix we show that a PQ symmetry common to both sectors allows a solution to the strong CP problem, with the axion mass enhanced by the mirror sector by a factor of order 103, leading to the possibility that fa is of order 10 TeV
The Twin Higgs mechanism significantly relaxes fine-tuning of the electroweak scale, and allows for a larger cut off scale
Summary
The quantum correction to the mass term is the most dangerous, and to suppress it we assume a Z2 symmetry H ↔ H and call H the mirror Higgs. In general we expect a fine tuning in the mass of the mirror Higgs boson. In composite Twin Higgs models, Λ is the scale of higher resonances, which is expected be as large as Λ ∼ g∗v , where g∗ is the coupling strength of hadron√s. In the supersymmetric Twin Higgs model, Λ is the stop mass scale multiplied by a log enhancement factor. Requiring that this correction does not exceed the required one in eq (2.9), we obtain yt − yt yt v /v 2 5 TeV 2. A key question becomes the form and origin of the Z2 breaking necessary to construct a fully realistic theory
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
