Abstract
In dimension-less theories of dynamical generation of the weak scale, the Universe can undergo a period of low-scale inflation during which all particles are massless and undergo super-cooling. This leads to a new mechanism of generation of the cosmological Dark Matter relic density: super-cooling can easily suppress the amount of Dark Matter down to the desired level. This is achieved for TeV-scale Dark Matter, if super-cooling ends when quark condensates form at the QCD phase transition. Along this scenario, the baryon asymmetry can be generated either at the phase transition or through leptogenesis. We show that the above mechanism takes place in old and new dimension-less models.
Highlights
Weak scale, see e.g. [1,2,3,4,5], and in attempts of building weak-scale extensions of the Standard Model valid up to infinite energy, such that no cut-off is needed [6,7,8,9]
Super-cooling erases the baryon asymmetry: we will discuss how it can be regenerated at the weak scale, possibly through leptogenesis
While we focus on simple models based on weakly-coupled elementary particles, supercool DM can arise in more generic contexts, such as strongly coupled models with walking dynamics [14], possibly described through broken conformal symmetries and/or through branes in warped extra dimensions [15]
Summary
We consider extensions of the SM that provide a DM candidate and where all particles get mass from the vacuum expectation value of a scalar s, sometimes called ‘dilaton’. In the standard freeze-out scenario, DM with mass MDM would decouple at a temperature Tdec, equal to Tdec ≈ MDM/25 if freeze-out reproduces the cosmological DM density
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
