# Can Baryon Acoustic Oscillations Illuminate the Parity-Violating Galaxy 4PCF?

**Authors:** Jiamin Hou, Zachary Slepian, Drew Jamieson  
**arXiv:** [2410.05230](https://arxiv.org/abs/2410.05230)  
**Date:** 2024-10-07  
**Summary page:** https://www.summarizepaper.com/en/paper/2410.05230v1/

## Key points

- Recent measurements of the galaxy 4-Point Correlation Function (4PCF) from SDSS BOSS reveal strong statistical evidence for parity violation
- The signal could potentially originate from beyond-Standard Model physics and date back to the early Universe before decoupling at a redshift of approximately $z$$\sim$$1,020
- Baryon Acoustic Oscillation (BAO) features imprinted at decoupling are expected to manifest in the parity-odd galaxy 4PCF
- Detecting BAO features in the parity-odd sector would provide compelling evidence supporting the observed signal's authenticity
- Authors present a toy parity-violating model demonstrating how BAO imprint on the parity-odd 4PCF and outline a strategy for conducting a model-independent search for BAO in the odd 4PCF
- If BAO are detected in the parity-odd sector, they can serve as a standard ruler akin to their utilization in conventional two-point and three-point correlation functions
- A formula establishes a relationship between precision on the BAO scale and overall detection significance in the parity-odd sector
- Future redshift surveys like DESI, Euclid, Spherex, and Roman are advocated for investigating BAO within the odd 4PCF to determine whether parity violation has genuine cosmological origins

## Summary

In their paper titled "Can Baryon Acoustic Oscillations Illuminate the Parity-Violating Galaxy 4PCF? ", authors Jiamin Hou, Zachary Slepian, and Drew Jamieson discuss recent measurements of the galaxy 4-Point Correlation Function (4PCF) from the Sloan Digital Sky Survey Baryon Oscillation Spectroscopic Survey (SDSS BOSS). These measurements have revealed strong statistical evidence for parity violation. This intriguing signal could potentially originate from beyond-Standard Model physics and date back to the very early Universe before decoupling at a redshift of approximately $z$$\sim$$1,020. The authors highlight that since the Baryon Acoustic Oscillation (BAO) features are imprinted at decoupling, they are expected to manifest in the parity-odd galaxy 4PCF. Detecting these BAO features in the parity-odd sector would provide additional compelling evidence supporting the authenticity of the observed signal. To further explore this phenomenon, the authors present a toy parity-violating model demonstrating how BAO imprint on the parity-odd 4PCF. Moreover, they outline a strategy for conducting a model-independent search for BAO in the odd 4PCF. This approach is deemed essential as it allows researchers to investigate potential inflation models responsible for generating the observed signal without preconceived biases. If BAO are indeed detected in the parity-odd sector, they can serve as a standard ruler akin to their utilization in conventional two-point and three-point correlation functions. The authors derive a straightforward formula that establishes a relationship between the expected precision on the BAO scale and overall detection significance in the parity-odd sector. They advocate for future redshift surveys such as DESI, Euclid, Spherex, and Roman to pursue investigations into BAO within the odd 4PCF as an invaluable avenue for determining whether parity violation in galaxy distribution has genuine cosmological origins. This comprehensive study not only sheds light on potential new physics beyond our current understanding but also underscores how exploring subtle cosmological signatures like Baryon Acoustic Oscillations can deepen our comprehension of fundamental aspects of our Universe.