Precision Early Universe Cosmology from Stochastic Gravitational Waves

Abstract

The causal tail of stochastic gravitational waves can be used to probe the energy density in free streaming relativistic species as well as measure $g_{\star }(T)$ and beta functions $\beta (T)$ as a function of temperature. In the event of the discovery of loud stochastic gravitational waves, we demonstrate that LISA can measure the free streaming fraction of the universe down to the the $10^{-3}$ level, 100 times more sensitive than current constraints. Additionally, it would be sensitive to $\mathcal{O}(1)$ deviations of $g_{\star }$ and the QCD $\beta$ function from their Standard Model value at temperatures $\sim 10^5$ GeV. In this case, many motivated models such as split SUSY and other solutions to the Electroweak Hierarchy problem would be tested. Future detectors, such as DECIGO, would be 100 times more sensitive than LISA to these effects and be capable of testing other motivated scenarios such as WIMPs and axions. The amazing prospect of using precision gravitational wave measurements to test such well motivated theories provides a benchmark to aim for when developing a precise understanding of the gravitational wave spectrum both experimentally and theoretically.

28 pages, 11 figures

References in corpus (10)

• Gravitational Wave Spectrum Induced by Primordial Scalar Perturbations
• Gravitational Waves from Phase Transitions at the Electroweak Scale and Beyond
• Theory and Numerics of Gravitational Waves from Preheating after Inflation
• Gravitational wave energy budget in strongly supercooled phase transitions
• Improved Calculation of the Primordial Gravitational Wave Spectrum in the Standard Model
• A Gravitational Wave Background from Reheating after Hybrid Inflation
• Gravitational Wave Production At The End Of Inflation
• A stochastic background of gravitational waves from hybrid preheating
• Relating gravitational wave constraints from primordial nucleosynthesis, pulsar timing, laser interferometers, and the CMB: implications for the early universe
• Induced gravitational waves as a probe of thermal history of the universe

Cited by in corpus (11)

• The Science of the Einstein Telescope
• The Scalar Singlet Extension of the Standard Model: Gravitational Waves versus Baryogenesis
• Primordial Black Hole Formation in Starobinsky's Linear Potential Model
• Primordial black holes as dark matter: Interferometric tests of phase transition origin
• Probing neutrino interactions and dark radiation with gravitational waves
• Precision cosmology with primordial GW backgrounds in presence of astrophysical foregrounds
• Magnetogenesis with gravitational waves and primordial black hole dark matter
• Gravitational-wave signatures from reheating
• Fundamental Physics and Cosmology with TianQin
• Reconstructing early universe evolution with gravitational waves from supercooled phase transitions
• Gravitational Wave Mountains: current-carrying domain walls