Light Particles with Spin in Inflation
  The existence of light particles with spin during inflation is prohibited by
the Higuchi bound. This conclusion can be evaded if one considers states with a
sizeable coupling with the inflaton foliation, since this breaks the de Sitter
isometries. The action for these states can be constructed within the Effective
Field Theory of Inflation, or using a CCWZ procedure. Light particles with spin
have prescribed couplings with soft inflaton perturbations, which are encoded
in consistency relations. We study the phenomenology of light states with spin
2. These mix with the graviton changing the tensor power spectrum and can lead
to sizeable tensor non-Gaussianities. They also give rise to a scalar
bispectrum and trispectrum with a characteristic angle-dependent
non-Gaussianity.
