Testing BSM Physics with Gravitational Waves

Abstract

The Cosmic Gravitational Wave Background (CGWB) is an irreducible background of gravitational waves generated by particle exchange in the early Universe plasma. Standard Model particles contribute to such a stochastic background with a peak at $f\sim 80$ GHz. Any physics beyond the Standard Model (BSM) may modify the CGWB spectrum, making it a potential testing ground for BSM physics. We consider the impact of general BSM scenarios on the CGWB, including an arbitrary number of hidden sectors. We find that the largest amplitude of the CGWB comes from the sector that dominates the energy density after reheating and confirm the dominance of the SM for standard cosmological histories. For non-standard cosmological histories, such as those with a stiff equation of state $\omega >1/3$, like in kination, BSM physics may dominate and modify the spectrum substantially. We conclude that, if the CGWB is detected at lower frequencies and amplitudes compared to that of the SM, it will hint at extra massive degrees of freedom or hidden sectors. If it is instead measured at higher values, it will imply a period with $\omega >1/3$. We argue that for scenarios with periods of kination in the early Universe, a significant fraction of the parameter space can be ruled out from dark radiation bounds at BBN.

arXiv comment16 pages + appendix, 7 figures v2: minor edits, references added. Matches published version

References in corpus (10)

• The Temperature of the Cosmic Microwave Background
• Cosmological Backgrounds of Gravitational Waves
• Challenges and Opportunities of Gravitational Wave Searches at MHz to GHz Frequencies
• Gravitational Waves as a Big Bang Thermometer
• Gravitational wave background from Standard Model physics: Qualitative features
• Gravitational wave background from Standard Model physics: Complete leading order
• Catch-Me-If-You-Can: The Overshoot Problem and the Weak/Inflation Hierarchy
• Primordial gravitational waves in a minimal model of particle physics and cosmology
• The rise of the primordial tensor spectrum from an early scalar-tensor epoch
• Thermal Emission of Gravitational Waves from Weak to Strong Coupling

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• Thermal Gravitons from Warm Inflation
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• Thermal evolution of dark matter and gravitational-wave production in the early universe from a symplectic glueball model
• Gauss-Bonnet Cosmology: large-temperature behaviour and bounds from Gravitational Waves
• Probing Gravitational Dark Matter with Ultra-high Frequency Gravitational Waves
• Stochastic gravitational wave from graviton bremsstrahlung in inflaton decay into massive spin 3/2 particles
• Imprints of an early matter-dominated era arising from dark matter dilution mechanism on cosmic string dynamics and gravitational wave signatures