# Probing Primordial Chirality with Galaxy Spins

## TL;DR

This paper proposes a method to detect primordial chiral symmetry violation by analyzing galaxy spin directions, which could reveal early Universe asymmetries through large-scale structure observations.

## Contribution

It introduces a novel helicity measurement using galaxy spins and large-scale structure clustering to probe primordial chiral symmetry breaking.

## Key findings

- Simulations show the spin mode correlates with galaxy spins.
- Standard model predicts symmetric correlation between helical components.
- Measurement sensitivity can test early Universe chiral symmetry breaking.

## Abstract

Chiral symmetry is maximally violated in weak interactions, and such microscopic asymmetries in the early Universe might leave observable imprints on astrophysical scales without violating the cosmological principle. In this Letter, we propose a helicity measurement to detect primordial chiral violation. We point out that observations of halo-galaxy angular momentum directions (spins), which are frozen in during the galaxy formation process, provide a fossil chiral observable. From the clustering mode of large scale structure of the Universe, we construct a spin mode in Lagrangian space and show in simulations that it is a good probe of halo-galaxy spins. In standard model, a strong symmetric correlation between the left and right helical components of this spin mode and galaxy spins is expected. Measurements of these correlations will be sensitive to chiral breaking, providing a direct test of chiral symmetry breaking in the early Universe.