Detecting higher-spin fields through statistical anisotropy in the CMB bispectrum

Inflation may provide a suitable collider to probe physics at very high energies. In this paper we investigate the impact on the CMB bispectrum of higher-spin fields which are long-lived on super-Hubble scales, e.g. partially massless higher-spin fields. We show that distinctive statistical anisotropic signals on the CMB three-point correlator are induced and we investigate their detectability.