A primordial spectrum of gravitational waves serves as a backlight to the relativistic degrees of freedom of the cosmological fluid. Any change in the particle physics content, due to a change of phase or freeze-out of a species, will leave a characteristic imprint on an otherwise featureless primordial spectrum of gravitational waves and indicate its early-Universe provenance. We show that a gravitational wave detector such as the Laser Interferometer Space Antenna (LISA) would be sensitive to physics near 100 TeV in the presence of a sufficiently strong primordial spectrum. Such a detection could complement searches at newly proposed 100 km circumference accelerators such as the Future Circular Collider at CERN and the Super Proton-Proton Collider in China, thereby providing insight into a host of beyond standard model issues, including the hierarchy problem, dark matter, and baryogenesis.
We describe bosonic mixing in curved spacetime in the presence of external, backgrounds field. We focus on axions and axion-like particles and describe the mixing with electromagnetic and gravitational waves. We describe the modified oscillation probabilities and (time-permitting) some of the observational consequences.
Zoom Info: https://yale.zoom.us/j/93903961284?pwd=empxRWhzdkY5SXpuQ2U2NmR1aWlpZz09
NPA Zoom Seminar, Devin Walker, Dartmouth College, “Two Stories at the Intersection of Particle Physics and Gravitational Waves”