# Shapes and features of the primordial bispectrum

## TL;DR

This paper introduces a new method to analyze scale-dependent features in the primordial bispectrum caused by inflationary disruptions, deriving consistency relations and proposing new templates for future CMB data analysis.

## Contribution

It presents a novel approach to study primordial bispectrum features, deriving consistency relations and constructing comprehensive templates for oscillating patterns.

## Key findings

- Derived new consistency relations among bispectrum shapes.
- Expressed cubic couplings in terms of local and equilateral configurations.
- Proposed new two-parameter templates encompassing known feature shapes.

## Abstract

If time-dependent disruptions from slow-roll occur during inflation, the correlation functions of the primordial curvature perturbation should have scale-dependent features, a case which is marginally supported from the cosmic microwave background (CMB) data. We offer a new approach to analyze the appearance of such features in the primordial bispectrum that yields new consistency relations and justifies the search of oscillating patterns modulated by orthogonal and local templates. Under the assumption of sharp features, we find that the cubic couplings of the curvature perturbation can be expressed in terms of the bispectrum in two specific momentum configurations, for example local and equilateral. This allows us to derive consistency relations among different bispectrum shapes, which in principle could be tested in future CMB surveys. Furthermore, based on the form of the consistency relations, we construct new two-parameter templates for features that include all the known shapes.