Probing Primordial Chirality in the Matter Distribution
arXiv:2607.26612
The authors develop a helicity‑based estimator to detect handedness in the large‑scale matter distribution as a signature of primordial parity violation, test it on simulations with parity‑violating initial conditions, and apply it to SDSS DR7 data, finding no statistically significant evidence.
Abstract
Whether parity symmetry was violated in the early universe remains one of the fundamental open questions in cosmology. If so, it may leave an intrinsic handedness in the large-scale matter distribution. Here we formulate a helicity-based estimator to measure this handedness. Using cosmological simulations with parity-violating initial conditions, we show that it survives nonlinear structure formation. Applying the estimator to density fields reconstructed from the SDSS DR7 galaxy catalog, we find mild deviations but statistically insignificant evidence for parity violation in the local universe. Our results establish the intrinsic handedness of the matter distribution as an observable relic of primordial parity violation, enabling a direct probe with current and future large-scale structure surveys.
4 pages, 2 figures. Comments welcome