Abstract
The dynamics of a cosmological (de)confinement phase transition is studied in nearly conformally invariant field theories, where confinement is predominantly spontaneously generated and associated with a light “dilaton” field. We show how the leading contribution to the transition rate can be computed within the dilaton effective theory. In the context of Composite Higgs theories, we demonstrate that a simple scenario involving two renormalization-group fixed points can make the transition proceed much more rapidly than in the minimal scenario, thereby avoiding excessive dilution of matter abundances generated before the transition. The implications for gravitational wave phenomenology are discussed. In general, we find that more (less) rapid phase transitions are associated with weaker (stronger) gravitational wave signals. The various possible features of the strongly coupled composite Higgs phase transition discussed here can be concretely modeled at weak coupling within the AdS/CFT dual Randall-Sundrum extra-dimensional description, which offers important insights into the nature of the transition and its theoretical control. These aspects will be presented in a companion paper.
Highlights
Coupling over a large hierarchy of scales, such as occurs in the domain of an approximate fixed point (FP) of the renormalization group (RG), and plausibly a large-N structure
Greater theoretical control of the strong dynamics is possible if the large-N approximate FP conformal field theory (CFT) has a useful Anti-de Sitter (AdS)/CFT dual description [16,17,18]
Reference [34] already argued for dilaton dominance in the RS context, but not completely within higher-dimensional effective field theory (EFT) control, and they showed that the PT cannot be prompt in the minimal RS model
Summary
We model the deconfined phase as an approximate CFT, coupled to gravity, with O(N 2) d.o.f. We model the small departure from conformal invariance by ∆L = gO, where O is a nearly-marginal composite operator and where the coupling g runs from the UV, but stops at the confinement scale, locally given by φ(x). This is the only way in which conformal invariance is broken within the compositeness dynamics, leading to an effective Lagrangian: N2 Leff = 16π2. This vacuum energy breaks conformal invariance but is only of gravitational relevance In this standard large-N “glueball” normalization (reviewed in [15, 48]), the self-coupling is expected to be λ ∼ 1. As we would expect, and will show in the appendix, the dominant finite-temperature bounce solutions are O(3) symmetric (and Euclidean time independent)
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
