Could sample variance be responsible for the parity-violating signal seen in the Baryon Oscillation Spectroscopic Survey?
Recent works have uncovered an excess signal in the parity-odd four-point correlation function measured from the Baryon Oscillation Spectroscopic Survey (BOSS) galaxy catalogue. If physical in origin, this could indicate new parity-breaking processes in inflation. At heart, these studies compare the...
| Autores: | , |
|---|---|
| Tipo de recurso: | artículo |
| Estado: | Versión aceptada para publicación |
| Fecha de publicación: | 2025 |
| País: | España |
| Institución: | Consejo Superior de Investigaciones Científicas (CSIC) |
| Repositorio: | DIGITAL.CSIC. Repositorio Institucional del CSIC |
| OAI Identifier: | oai:digital.csic.es:10261/381972 |
| Acceso en línea: | http://hdl.handle.net/10261/381972 |
| Access Level: | acceso abierto |
| Palabra clave: | Large-scale structure Correlation functions Inflation Simulations |
| Sumario: | Recent works have uncovered an excess signal in the parity-odd four-point correlation function measured from the Baryon Oscillation Spectroscopic Survey (BOSS) galaxy catalogue. If physical in origin, this could indicate new parity-breaking processes in inflation. At heart, these studies compare the observed four-point correlator with the distribution obtained from parity-conserving mock galaxy surveys; if the simulations underestimate the covariance of the data, noise fluctuations may be misinterpreted as a signal. To test this, we reanalyse the BOSS CMASS parity-odd dataset with the noise distribution model using the newly developed GLAM-UCHUU suite of mocks. These comprise full N -body simulations that follow the evolution of 20003 dark matter particles and represent a significant upgrade compared with the formerly used MultiDark-Patchy mocks, which were based on an alternative (non N -body) gravity solver. We find no significant evidence for parity-violation (with a baseline detection significance of 1.0 σ ), suggesting that the former signal (2.9 σ with our data cuts) could be caused by an underestimation of the covariance in MultiDark-Patchy. The significant differences between results obtained with the two sets of BOSS-calibrated galaxy catalogues (whose covariances differ at the 10 − 20 % level) showcase the heightened sensitivity of beyond-two-point analyses to nonlinear effects and indicate that previous constraints may suffer from large systematic uncertainties. © 2025 The Author(s). |
|---|