Planck Constraints on Axion-Like Particles through Isotropic Cosmic Birefringence

TL;DR

This paper uses Planck CMB polarization data to constrain axion-like particles as a cause of isotropic cosmic birefringence, providing new limits on ALP parameters and excluding certain mass ranges with high confidence.

Contribution

It introduces a comprehensive likelihood framework for analyzing ALP-induced birefringence in CMB data, improving upon previous methods and constraining ALP models more effectively.

Findings

Excluded specific ALP mass ranges at >2 sigma significance.

Developed a simplified yet comprehensive likelihood analysis method.

Provided constraints on ALP parameters consistent with Planck data.

Abstract

We present constraints on isotropic cosmic birefringence induced by axion-like particles (ALPs), derived from the analysis of cosmic microwave background (CMB) polarization measurements obtained with the high-frequency channels of Planck. Recent measurements report a hint of isotropic cosmic birefringence, though its origin remains uncertain. The detailed dynamics of ALPs can leave characteristic imprints on the shape of the $EB$ angular power spectrum, which can be exploited to constrain specific models of cosmic birefringence. We first construct a multi-frequency likelihood that incorporates an intrinsic nonzero $EB$ power spectrum. We also show that the likelihood used in previous studies can be further simplified without loss of generality. Using this framework, we simultaneously constrain the ALP model parameters, the instrumental miscalibration angle, and the amplitudes of the $EB$ power spectrum of a Galactic dust foreground model. We find that, if ALPs are responsible for the observed cosmic birefringence, ALP masses at $\log_{10}m_{\phi}[{\rm eV}]\simeq-27.8$, $-27.5$, $-27.3$, $-27.2$, $-27.1$, as well as $\log_{10}m_{\phi}[{\rm eV}]\in[-27.0,-26.5]$, are excluded at more than $2\,\sigma$ statistical significance.