New sensitivity curves for gravitational-wave signals from cosmological phase transitions

Abstract

Gravitational waves (GWs) from strong first-order phase transitions (SFOPTs) in the early Universe are a prime target for upcoming GW experiments. In this paper, I construct novel peak-integrated sensitivity curves (PISCs) for these experiments, which faithfully represent their projected sensitivities to the GW signal from a cosmological SFOPT by explicitly taking into account the expected shape of the signal. Designed to be a handy tool for phenomenologists and model builders, PISCs allow for a quick and systematic comparison of theoretical predictions with experimental sensitivities, as I illustrate by a large range of examples. PISCs also offer several advantages over the conventional power-law-integrated sensitivity curves (PLISCs); in particular, they directly encode information on the expected signal-to-noise ratio for the GW signal from a SFOPT. I provide semianalytical fit functions for the exact numerical PISCs of LISA, DECIGO, and BBO. In an appendix, I moreover present a detailed review of the strain noise power spectra of a large number of GW experiments. The numerical results for all PISCs, PLISCs, and strain noise power spectra presented in this paper can be downloaded from the Zenodo online repository [1]. In a companion paper [2], the concept of PISCs is used to perform an in-depth study of the GW signal from the cosmological phase transition in the real-scalar-singlet extension of the standard model. The PISCs presented in this paper will need to be updated whenever new theoretical results on the expected shape of the signal become available. The PISC approach is therefore suited to be used as a bookkeeping tool to keep track of the theoretical progress in the field.

Multi-Field versus Single-Field in the Supergravity Models of Inflation and Primordial Black Holes

“…We have used the power-law integrated curves [80] and have applied them to the LISA noise model [81,82]. As the alternative, the peak-integrated curves can be used [83]). To draw the sensitivity curves, we have used the parameters and the noise models for TianQin [84], Taiji [85], and DECIGO [86].…”

Dark holograms and gravitational waves

“…Examples of GW power spectra h 2 Ω GW due to bubble collisions (Ω c , dashed lines) and sound waves in the case of short source duration (Ω sw,q , continuous lines) and long source duration (Ω sw , dotted lines). Expected sensitivities (PLISCs) for a number of experimental facilities are reported for comparison [52]. From left to right, the spectra correspond to the following parameters: (M KK /GeV, g) = (10 −4 , 5 • 10 3 ) (blue lines), (10 2 , 10 6 ), (10 6 , 10 6 ) (green lines), (10 9 , 10 3 ) (red lines).…”

“…The first type is the confinement transition, possibly implying a chiral symmetry breaking transition. [52]) and examples of theoretical GW power spectra from sound waves. In green, the sum of the signal from the confinement transition with λ = N = 10, M KK = 100 GeV and that from the chiral symmetry transition with N f = 1,f χ = 60.…”

Gravitational wave signatures from domain wall and strong first-order phase transitions in a two complex scalar extension of the Standard Model

“…In the left panel of figure 3 we show the GW intensity from domain walls for our selected five BPs whereas in the right panel of figure 3 the GW intensity from phase transition for the same BPs are plotted. We perform a direct comparison between our calculated modeldependent GW intensity with the sensitivity plots [112] of PTAs such as SKA, IPTA, EPTA, PPTA, NANOGrav11 and NANOGrav12.5 for the domain wall case and found JHEP05(2021)223 that the calculations using BP 4 lie within the sensitivity curves of SKA and IPTA. It can be noted that calculations using BP 4 yield higher GW intensity compared to the results of other BPs when GWs from domain walls are considered but the GWs from first-order phase transition cannot be obtained if BP 4 is used for the calculation.…”