TY - JOUR

T1 - Detecting circular polarisation in the stochastic gravitational-wave background from a first-order cosmological phase transition

AU - Ellis, John

AU - Fairbairn, Malcolm

AU - Lewicki, Marek

AU - Vaskonen, Ville

AU - Wickens, Alastair

PY - 2020/10

Y1 - 2020/10

N2 - We discuss the observability of circular polarisation of the stochastic gravitational-wave background (SGWB) generated by helical turbulence following a first-order cosmological phase transition, using a model that incorporates the effects of both direct and inverse energy cascades. We explore the strength of the gravitational-wave signal and the dependence of its polarisation on the helicity fraction, ζ∗, the strength of the transition, α, the bubble size, R∗, and the temperature, T∗, at which the transition finishes. We calculate the prospective signal-to-noise ratios of the SGWB strength and polarisation signals in the LISA experiment, exploring the parameter space in a way that is minimally sensitive to the underlying particle physics model. We find that discovery of SGWB polarisation is generally more challenging than measuring the total SGWB signal, but would be possible for appropriately strong transitions with large bubble sizes and a substantial polarisation fraction.

AB - We discuss the observability of circular polarisation of the stochastic gravitational-wave background (SGWB) generated by helical turbulence following a first-order cosmological phase transition, using a model that incorporates the effects of both direct and inverse energy cascades. We explore the strength of the gravitational-wave signal and the dependence of its polarisation on the helicity fraction, ζ∗, the strength of the transition, α, the bubble size, R∗, and the temperature, T∗, at which the transition finishes. We calculate the prospective signal-to-noise ratios of the SGWB strength and polarisation signals in the LISA experiment, exploring the parameter space in a way that is minimally sensitive to the underlying particle physics model. We find that discovery of SGWB polarisation is generally more challenging than measuring the total SGWB signal, but would be possible for appropriately strong transitions with large bubble sizes and a substantial polarisation fraction.

KW - cosmological phase transitions

KW - Magnetohydrodynamics

KW - physics of the early universe

KW - primordial gravitational waves (theory)

UR - http://www.scopus.com/inward/record.url?scp=85094187517&partnerID=8YFLogxK

U2 - 10.1088/1475-7516/2020/10/032

DO - 10.1088/1475-7516/2020/10/032

M3 - Article

AN - SCOPUS:85094187517

SN - 1475-7516

VL - 2020

JO - Journal of Cosmology and Astroparticle Physics

JF - Journal of Cosmology and Astroparticle Physics

IS - 10

M1 - 032

ER -