Alleviating CMB-BAO tension with a large cosmic birefringence angle during reionization induced by energy injection to axion-like particles
Abstract
The recent measurement of baryon acoustic oscillations by the Dark Energy Spectroscopic Instrument reveals a mild tension with observations of the cosmic microwave background (CMB) within the standard ΛCDM cosmological model. Another interesting hint beyond standard cosmology arises from recent analyses of Planck polarization data which has been interpreted as cosmic birefringence. One possible solution to explain both observations is to introduce cosmic birefringence induced by axion-like particles (ALPs) that has a much larger rotation angle during the reionization epoch than that during the recombination: the large rotation suppresses the EE reionization signal, allowing an elevated value of the CMB optical depth τ that alleviates the CMB-BAO tension. In this paper, we explore a scenario where the energy transfers from matter to ALPs before the reionization. Using Planck low-ℓ EE, BB, and EB data, we show that, for energy injection at 10 ≲ z ≲ 100, there exist parameter regions where τ≃ 0.08−0.10 is compatible with the data.
Related
- Cosmic birefringence tomography with radio galaxies I: Testing birefringence solutions to the CMB-BAO tension
- Alleviating the Hubble Tension Using Coupled Dark Energy - Dark Matter Interaction
- The Atacama Cosmology Telescope: DR6 Constraints on Isotropic Time-Dependent Cosmic Birefringence from Axion-like Particles
- Vacuum birefringence and the polarized X-ray emission from a radio magnetar
- De-lensing cosmic birefringence with joint reconstruction
BibTeX
@misc{sirletti2026alleviating,
title = {{Alleviating CMB-BAO tension with a large cosmic birefringence angle during reionization induced by energy injection to axion-like particles}},
author = {Salvatore Samuele Sirletti and Toshiya Namikawa and Blake D. Sherwin},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.29764},
eprint = {2610.29764},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.29764},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Alleviating CMB-BAO tension with a large cosmic birefringence angle during reionization induced by energy injection to axion-like particles
AU - Salvatore Samuele Sirletti
AU - Toshiya Namikawa
AU - Blake D. Sherwin
PY - 2026
DA - 2026/10/21
PB - arXiv
DO - 10.48550/arxiv.2610.29764
UR - https://arxiv.org/abs/2610.29764
AB - The recent measurement of baryon acoustic oscillations by the Dark Energy Spectroscopic Instrument reveals a mild tension with observations of the cosmic microwave background (CMB) within the standard ΛCDM cosmological model. Another interesting hint beyond standard cosmology arises from recent analyses of Planck polarization data which has been interpreted as cosmic birefringence. One possible solution to explain both observations is to introduce cosmic birefringence induced by axion-like particles (ALPs) that has a much larger rotation angle during the reionization epoch than that during the recombination: the large rotation suppresses the EE reionization signal, allowing an elevated value of the CMB optical depth τ that alleviates the CMB-BAO tension. In this paper, we explore a scenario where the energy transfers from matter to ALPs before the reionization. Using Planck low-ℓ EE, BB, and EB data, we show that, for energy injection at 10 ≲ z ≲ 100, there exist parameter regions where τ≃ 0.08−0.10 is compatible with the data.
ER -