5 papers
Primordial Correlators from a Kaluza-Klein Graviton Continuum
Shuntaro Aoki
Cosmological collider signals are usually discussed for isolated massive particles, whose exchange produces characteristic logarithmic oscillations in primordial correlators. In th…
Fermionic Bubble Loop in Cosmological Collider Revisited: Exact signals from spectral and Mellin-Barnes methods
Shuntaro Aoki, Zhehan Qin, Masahide Yamaguchi +1
Fermionic degrees of freedom are essential ingredients in cosmological collider physics and are well motivated by many phenomenological models beyond the Standard Model, but their…
Cosmological collider signals of modular spontaneous CP breaking
Shuntaro Aoki, Alessandro Strumia
We consider a modular-invariant extension of the Standard Model. Assuming that the modulus is the inflaton, the CP-violating phases of the Yukawa couplings evolve during inflation.…
Testing the arrow of time at the cosmo collider
Shuntaro Aoki, Alessandro Strumia
Normal particles carry a microscopic arrow of causality. Lee-Wick ghosts carry the reversed arrow, mediating characteristic collider signals in flat space: opposite-sign scattering…
Cosmological collider non-Gaussianity from multiple scalars and gravity
Shuntaro Aoki, Anish Ghoshal, Alessandro Strumia
Cosmological collider signals of primordial non-Gaussianity arise at tree level when an extra scalar has Hubble mass during inflation. We critically review the formalism finding th…