Cosmological signatures of a mirror twin Higgs

Zackaria Chacko, David Curtin, Michael Geller, Yuhsin Tsai*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

60 Scopus citations


We explore the cosmological signatures associated with the twin baryons, electrons, photons and neutrinos in the Mirror Twin Higgs framework. We consider a scenario in which the twin baryons constitute a subcomponent of dark matter, and the contribution of the twin photon and neutrinos to dark radiation is suppressed due to late asymmetric reheating, but remains large enough to be detected in future cosmic microwave background (CMB) experiments. We show that this framework can lead to distinctive signals in large scale structure and in the cosmic microwave background. Baryon acoustic oscillations in the mirror sector prior to recombination lead to a suppression of structure on large scales, and leave a residual oscillatory pattern in the matter power spectrum. This pattern depends sensitively on the relative abundances and ionization energies of both twin hydrogen and helium, and is therefore characteristic of this class of models. Although both mirror photons and neutrinos constitute dark radiation in the early universe, their effects on the CMB are distinct. This is because prior to recombination the twin neutrinos free stream, while the twin photons are prevented from free streaming by scattering off twin electrons. In the Mirror Twin Higgs framework the relative contributions of these two species to the energy density in dark radiation is predicted, leading to testable effects in the CMB. These highly distinctive cosmological signatures may allow this class of models to be discovered, and distinguished from more general dark sectors.

Original languageEnglish
Article number163
JournalJournal of High Energy Physics
Issue number9
StatePublished - 1 Sep 2018
Externally publishedYes


FundersFunder number
Maryland Center for Fundamental Physics
National Science FoundationPHY-1620074, PHY-1066293
Directorate for Mathematical and Physical Sciences1066293
Aspen Center for Physics
Association of Canadian Universities for Research in Astronomy


    • Beyond Standard Model
    • Cosmology of Theories beyond the SM


    Dive into the research topics of 'Cosmological signatures of a mirror twin Higgs'. Together they form a unique fingerprint.

    Cite this