Dark Matter production from relativistic bubble walls

A strongly-coupled sector can feature a supercooled confinement transition in the early universe. We point out that, when fundamental quanta of the strong sector are swept into expanding bubbles of the confined phase, the distance between them is large compared to the confinement scale. We suggest a modelling of the subsequent dynamics and find that the flux linking the fundamental quanta deforms and stretches towards the wall, producing an enhanced number of composite states upon string fragmentation. The composite states are highly boosted in the plasma frame, which leads to additional particle production through the subsequent deep inelastic scattering. We study the consequences for the abundance and energetics of particles in the universe and for bubble-wall Lorentz factors. This opens several new avenues of investigation, which we begin to explore here, showing that the composite dark matter relic density is affected by many orders of magnitude.

mentioning

confidence: 99%

String fragmentation in supercooled confinement and implications for dark matter

Baldes

Gouttenoire

Sala

2021

“…Even in a hidden U (1) symmetry breaking, which will be our concrete example, and which are also studied in the context of the topological defects, our mechanism provides complementary parameter regions. Heavy DM production, other than the ALP or hidden photon, in association with the first order phase transition (PT) by coupling the DM to certain Higgs fields, has been discussed [53][54][55][56][57]. Compared with those studies, our DM is 1 The most misalignment production mechanisms of the hidden photon suffer from theoretical inconsistency or observational constraints [19].…”

Section: Jhep10(2021)026mentioning

confidence: 99%

Hidden photon and axion dark matter from symmetry breaking

Nakayama

Yin

2021

Self Cite

A light hidden photon or axion-like particle is a good dark matter candidate and they are often associated with the spontaneous breaking of dark global or gauged U(1) symmetry. We consider the dark Higgs dynamics around the phase transition in detail taking account of the portal coupling between the dark Higgs and the Standard Model Higgs as well as various thermal effects. We show that the (would-be) Nambu-Goldstone bosons are efficiently produced via a parametric resonance with the resonance parameter q ∼ 1 at the hidden symmetry breaking. In the simplest setup, which predicts a second order phase transition, this can explain the dark matter abundance for the axion or hidden photon as light as sub eV. Even lighter mass, as predicted by the QCD axion model, can be consistent with dark matter abundance in the case of first order phase transition, in which case the gravitational wave signals may be detectable by future experiments such as LISA and DECIGO.

“…Armed with the generic expression in eq. (2.7) we can proceed to the computation of the light → heavy transition probability similarly to the discussion in [1,21],…”

Section: Probability Of the Light → Heavy Transitionmentioning

confidence: 99%

Baryogenesis via relativistic bubble walls

Azatov

Vanvlasselaer

Yin

2021

Self Cite

We present a novel mechanism which leads to the baryon asymmetry generation during the strong first order phase transition. If the bubble wall propagates with ultra-relativistic velocity, it has been shown [1] that it can produce states much heavier than the scale of the transition and that those states are then out of equilibrium. In this paper, we show that this production mechanism can also induce CP-violation at one-loop level. We calculate those CP violating effects during the heavy particle production and show, that combined with baryon number violating interactions, those can lead to successful baryogenesis. Two models based on this mechanism are constructed and their phenomenology is discussed. Stochastic gravitational wave signals turn out to be generic signatures of this type of models.