SPHEREx Inflationary Model Predictions and the Search for Non-Gaussianity

Field-number agnostic predictions to Inflationary theory produce non-gaussian perturba-

tions of any order, but theory-specific ranges. The scope of these predictions is dependent

on not only the number of interacting fields the model assumes but also the orientation of

the wavevectors within the expansion, the second of which imprints a unique form within

the CMB. In this work, we leverage that the forecasts of the non-gaussianity that are pro-

duced under inflationary potential reconstruction result in more concrete limitations of

the theories describing inflation. Focusing on current CMB observations from PLANCK

and upcoming forecasts by SPHEREx, the relevant scale within our work is the low-

interacting limit i.e. single field or single field dominated inflation, in which the relevant

CMB angular scales are related to the orientation of the wavevectors of the inflation itself.

We connect these predictions to the current and future observational insights, introducing

a flexible yet still accurate test for inflationary models in the light of SPHEREx forecasts.