# Item

ITEM ACTIONSEXPORT

Released

Journal Article

#### A fresh look at the gravitational-wave signal from cosmological phase transitions

##### MPS-Authors

##### External Resource

No external resources are shared

##### Fulltext (public)

There are no public fulltexts stored in PuRe

##### Supplementary Material (public)

There is no public supplementary material available

##### Citation

Alanne, T., Hugle, T., Platscher, M., & Schmitz, K. (2020). A fresh look at the
gravitational-wave signal from cosmological phase transitions.* Journal of high energy physics: JHEP,*
*2020*(3): 004. doi:10.1007/JHEP03(2020)004.

Cite as: http://hdl.handle.net/21.11116/0000-0008-2075-0

##### Abstract

Many models of physics beyond the Standard Model predict a strong first-order phase transition (SFOPT) in the early Universe that leads to observable gravitational waves (GWs). In this paper, we propose a novel method for presenting and comparing the GW signals that are predicted by different models. Our approach is based on the observation that the GW signal has an approximately model-independent spectral shape. This allows us to represent it solely in terms of a finite number of observables, that is, a set of peak amplitudes and peak frequencies. As an example, we consider the GW signal in the real-scalar-singlet extension of the Standard Model (xSM). We construct the signal region of the xSM in the space of observables and show how it will be probed by future space-borne interferometers. Our analysis results in sensitivity plots that are reminiscent of similar plots that are typically shown for dark-matter direct-detection experiments, but which are novel in the context of GWs from a SFOPT. These plots set the stage for a systematic model comparison, the exploration of underlying model-parameter dependencies, and the construction of distribution functions in the space of observables. In our plots, the experimental sensitivities of future searches for a stochastic GW signal are indicated by peak-integrated sensitivity curves. A detailed discussion of these curves, including fit functions, is contained in a companion paper [1].