Cosmological Collider Physics provides information on high-energy elementary
particles by observing the spacetime fluctuations generated by inflation
through the cosmic microwave background radiation. In other words, it is a
method to investigate physics on energy scales that cannot be reached by
terrestrial accelerators by means of precise observations of the universe. In
this paper, we focus on the case where the GUT scale is close to the energy
scale of inflation, and calculate the non-Gaussianity due to scalar
fluctuations produced by the Higgs boson in GUT. The results are found to be
consistent with the current observed restrictions on non-Gaussianity without a
drastic fine tuning of parameters, which suggests the existence of Higgs boson
in GUT.
