Effects of Radiation on Primordial Non-Gaussianity

We study the non-Gaussian features in single-field slow-roll inflationary scenario where inflation is preceded by a radiation era. In such a scenario both bispectrum and trispectrum non-Gaussianities are enhanced. Interestingly, the trispectrum in this scenario does not depend up on the slow-roll parameters and thus ${\tau }_{NL}$ is larger than $f_{NL}$ which can be a signature of such a pre-inflationary radiation era.