Primordial Standard Clock Models and CMB Residual Anomalies

TL;DR

This paper develops a primordial standard clock model to explain CMB residual anomalies, fitting current data well and predicting future distinguishability with improved polarization measurements.

Contribution

It introduces a novel primordial standard clock model linking CMB anomalies across scales, providing a new approach to probe early universe history.

Findings

Model fits CMB anomalies well

Current models are statistically indistinguishable from Standard Model

Future data may distinguish models with higher quality polarization measurements

Abstract

The residuals of the power spectra of WMAP and Planck's cosmic microwave background (CMB) anisotropies data are known to exhibit a few interesting anomalies at different scales with marginal statistical significance. Combining bottom-up and top-down model-building approaches and using a pipeline that efficiently compares model predictions with data, we construct a model of primordial standard clock that is able to link and address the anomalies at both the large and small scales. This model, and its variant, provide some of the best fits to the feature anomalies in CMB. According to Bayes evidences, these models are currently statistically indistinguishable from the Standard Model. We show that the difference between them will soon become statistically significant with various higher quality data on the CMB polarization. We demonstrate that such a model-building and data-analyses process may be used to uncover a portion of detailed evolutionary history of our universe during its primordial epoch.