Constraints on long-lived, higher-spin particles from galaxy bispectrum

Understand

The presence of massive particles with spin during inflation induces distinct signatures on correlation functions of primordial curvature fluctuations.

• In particular, the bispectrum of primordial perturbations obtains an angular dependence determined by the spin of the particle, which can be used to set constraints on the presence of such particles.
• If these particles are long-lived on super-Hubble scales, as is the case for example for partially massless particles, their imprint on correlation functions of curvature perturbations would be unsuppressed.
• In this paper, we make a forecast for how well such angular dependence can be constrained by the upcoming EUCLID spectroscopic survey via the measurement of galaxy bispectrum.