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Register a new userObservational prospects for gravitational waves from hidden or dark chiral phase transitions
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Alexander Helmboldt
Publication date
2019
fields
Physics
and research's language is
English
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We study the gravitational wave (GW) signature of first-order chiral phase transitions ($chi$PT) in strongly interacting hidden or dark sectors. We do so using several effective models in order to reliably capture the relevant non-perturbative dynamics. This approach allows us to explicitly calculate key quantities characterizing the $chi$PT without having to resort to rough estimates. Most importantly, we find that the transitions inverse duration $beta$ normalized to the Hubble parameter $H$ is at least two orders of magnitude larger than typically assumed in comparable scenarios, namely $beta/Hgtrsimmathcal{O}(10^4)$. The obtained GW spectra then suggest that signals from hidden $chi$PTs occurring at around 100 MeV can be in reach of LISA, while DECIGO and BBO may detect a stochastic GW background associated with transitions between roughly 1 GeV and 10 TeV. Signatures of transitions at higher temperatures are found to be outside the range of any currently proposed experiment. Even though predictions from different effective models are qualitatively similar, we find that they may vary considerably from a quantitative point of view, which highlights the need for true first-principle calculations such as lattice simulations.
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First order phase transitions in the early Universe generate gravitational waves, which may be observable in future space-based gravitational wave observatiories, e.g. the European eLISA satellite constellation. The gravitational waves provide an unprecedented direct view of the Universe at the time of their creation. We study the generation of the gravitational waves during a first order phase transition using large-scale simulations of a model consisting of relativistic fluid and an order parameter field. We observe that the dominant source of gravitational waves is the sound generated by the transition, resulting in considerably stronger radiation than earlier calculations have indicated.
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