Emergent/Composite axions

Understand

Hidden theories coupled to the SM may provide emergent axions, that are composites/bound-states of the hidden fields.

• This is motivated by paradigms emerging from the AdS/CFT correspondence but it is a more general phenomenon.
• We explore the general setup and find that UV-sourced interactions of instanton densities give rise to emergent axions in the IR.
• We study the general properties of such axions and argue that they are generically different from both fundamental and composite axions that have been studied so far.