Dark matter, dark radiation and gravitational waves from mirror Higgs parity
David Dunsky, Lawrence J. Hall, Keisuke Harigaya
Abstract
Abstract An exact parity replicates the Standard Model giving a Mirror Standard Model, SM ↔ SM ′ . This “Higgs Parity” and the mirror electroweak symmetry are spontaneously broken by the mirror Higgs, 〈 H ′ 〉 = v ′ ≫ 〈 H 〉, yielding the Standard Model Higgs as a Pseudo-Nambu-Goldstone Boson of an approximate SU (4) symmetry, with a quartic coupling λ SM ( v ′ ) ∼ 10 − 3 . Mirror electromagnetism is unbroken and dark matter is composed of e ′ and $$ {\overline{e}}^{\prime } $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msup> <mml:mover> <mml:mi>e</mml:mi> <mml:mo>¯</mml:mo> </mml:mover> <mml:mo>′</mml:mo> </mml:msup> </mml:math> . Direct detection may be possible via the kinetic mixing portal, and in unified theories this rate is correlated with the proton decay rate. With a high reheat temperature after inflation, the e t dark matter abundance is determined by freeze-out followed by dilution from decays of mirror neutrinos, ν ′ → ℓH . Remarkably, this requires v ′ ∼ (10 8 –10 10 ) GeV, predicting a Higgs mass of 123 ± 3 GeV at 1 σ and a Standard Model neutrino mass of (10 − 2 –10 − 1 ) eV, consistent with observed neutrino masses. The mirror QCD sector exhibits a first order phase transition producing gravitational waves that may be detected by future observations. Mirror glueballs decay to mirror photons giving dark radiation with ∆ N eff ∼ 0 . 03–0 . 4. With a low reheat temperature after inflation, the e ′ dark matter abundance is determined by freeze-in from the SM sector by either the Higgs or kinetic mixing portal.