# Consistency of CMB experiments beyond cosmic variance

## TL;DR

This paper explores the potential of upcoming CMB experiments to perform consistency tests that can detect instrumental systematics with precision surpassing cosmic variance limitations.

## Contribution

It introduces new consistency tests for future CMB data, quantifies expected cosmological parameter shifts, and forecasts measurements of instrumental systematics like T-to-E leakage.

## Key findings

- Instrumental systematics can be constrained with high precision.
- Consistency tests can detect shifts beyond cosmic variance.
- Forecasts show potential for precise systematic assessments.

## Abstract

The next generation of Cosmic Microwave Background experiments will produce cosmic variance limited observations over a large fraction of sky and for a large range of multipoles. In this work we discuss different consistency tests that can be performed with the upcoming data from the Simons Observatory and the Planck data. We quantify the level of expected cosmological parameter shifts probed by these tests. We discuss the effect of difference in frequency of observation and present forecasts on a direct measurement of the Planck T-to-E leakage beam. We find that instrumental systematics in either of the experiments will be assessed with an exquisite precision, well beyond the intrinsic uncertainties due to the CMB cosmic variance.