Abstract
We present the conformal freeze-in (COFI) scenario for dark matter production. At high energies, the dark sector is described by a gauge theory flowing towards a Banks-Zaks fixed point, coupled to the standard model via a non-renormalizable portal interaction. At the time when the dark sector is populated in the early universe, it is described by a strongly coupled conformal field theory. As the universe cools, cosmological phase transitions in the standard model sector, either electroweak or QCD, induce conformal symmetry breaking and confinement in the dark sector. One of the resulting dark bound states is stable on the cosmological time scales and plays the role of dark matter. With the Higgs portal, the COFI scenario provides a viable dark matter candidate with mass in a phenomenologically interesting 0.1-1 MeV range. With the quark portal, a dark matter candidate with mass around 1 keV is consistent with observations. Conformal bootstrap puts a non-trivial constraint on model building in this case.
Highlights
Microscopic nature of dark matter is one of the central open questions in fundamental physics which cannot be addressed within the Standard Model (SM)
We show how dark matter can arise from a new physics sector which is described by a conformal field theory (CFT) throughout most of its cosmological history
The physics is completely different: our dark sector is strongly coupled, the operator OCFT has a nonperturbatively large anomalous dimension and is genuinely conformally invariant
Summary
Microscopic nature of dark matter is one of the central open questions in fundamental physics which cannot be addressed within the Standard Model (SM). While the precise nature of the dark matter sector varies greatly among the proposed models, all of them postulate that dark matter consists of pointlike particles (e.g., weakly interacting massive particles or axions), their bound states (e.g., dark atoms), or particlelike extended objects (monopoles, Q-balls, etc.), both today and throughout its cosmological history. Viable extensions of the SM exist in which new physics sectors do not contain spatially localized particlelike excitations at all [2]. Any interactions of the CFT sector with the nonconformally invariant SM inevitably break the symmetry Such effects induce a “gap” mass scale, below which the sector is no longer conformal and its spectrum consists of spatially localized particle degrees of freedom. The gap scale, which is induced by cosmological phase transitions in SM, is sufficiently large so that the dark sector behaves as nonrelativistic matter during CMB decoupling, structure formation, and today, as required by observations
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
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 call
