Parametric tension between even and odd multipole data of WMAP power spectrum: unaccounted contamination or missing parameters?

TL;DR

The paper investigates the tension between even and odd multipole data in the WMAP power spectrum, revealing inconsistencies with the concordance model that may suggest contamination or missing parameters.

Contribution

It identifies and analyzes the tension between even and odd multipole data in the WMAP spectrum and explores potential causes like contamination or missing parameters.

Findings

WMAP concordance model poorly fits even/odd multipole data

Tension is highest in primordial power spectrum parameters

Adding a running spectral index increases tension

Abstract

There exist power contrast in even and odd multipoles of WMAP power spectrum at low and intermediate multipole range. This anomaly is explicitly associated with the angular power spectrum, which are heavily used for cosmological model fitting. Having noted this, we have investigated whether even(odd) multipole data set is consistent with the WMAP concordance model. Our investigation shows WMAP concordance model does not make a good fit for even(odd) multipole data set, and there exist tension between two data subsets. Noting tension is highest in primordial power spectrum parameters, we have additionally considered a running spectral index, but find tension increases to even a higher level. We believe these parametric tensions may be indications of unaccounted contamination or imperfection of the model.