In Search of Large Signals at the Cosmological Collider
  We look for oscillating signals in the primordial bispectrum from new physics
heavy particles which are visibly large for next generation large scale
structures (LSS) survey. We show that in ordinary inflation scenarios where a
slow-rolling inflaton generates density fluctuations and with no breaking of
scale invariance or spacetime symmetry, there exist no naturally large signals
unless the rolling inflaton generates a parity-odd chemical potential for the
heavy particles. We estimate the accessibility of this signal through
observations. While current CMB data are already sensitive in the most
optimistic scenario, future probes, including LSS survey and 21 cm observation,
can cover interesting regions of the model space.
