# Weak lensing forecasts for dark energy, neutrinos and initial conditions

## TL;DR

This paper demonstrates that all-sky weak lensing surveys, combined with CMB data, can effectively constrain dark energy, neutrino masses, and primordial power spectrum parameters, including a new second order running spectral index.

## Contribution

It introduces a new parameter for primordial spectrum analysis and evaluates how weak lensing combined with CMB priors constrains multiple cosmological sectors simultaneously.

## Key findings

- Weak lensing with CMB priors yields robust dark energy constraints.
- Weak lensing can simultaneously constrain neutrino masses and primordial spectrum.
- Dark energy constraints are largely unaffected by other sectors.

## Abstract

Weak gravitational lensing provides a sensitive probe of cosmology by measuring the mass distribution and the geometry of the low redshift universe. We show how an all-sky weak lensing tomographic survey can jointly constrain different sets of cosmological parameters describing dark energy, massive neutrinos (hot dark matter), and the primordial power spectrum. In order to put all sectors on an equal footing, we introduce a new parameter $\beta$, the second order running spectral index. Using the Fisher matrix formalism with and without CMB priors, we examine how the constraints vary as the parameter set is enlarged. We find that weak lensing with CMB priors provides robust constraints on dark energy parameters and can simultaneously provide strong constraints on all three sectors. We find that the dark energy sector is largely insensitive to the inclusion of the other cosmological sectors. Implications for the planning of future surveys are discussed.