Cosmic Birefringence from CP-Violating Axion Interactions
Fuente:
arXiv
Gespeichert in:
| Hauptverfasser: | , |
|---|---|
| Format: | Preprint |
| Veröffentlicht: |
2023
|
| Schlagworte: | |
| Online-Zugang: | |
| Tags: |
Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
|
| _version_ | 1866916354610692096 |
|---|---|
| author | Luo, Xuheng Mathur, Anubhav |
| author_facet | Luo, Xuheng Mathur, Anubhav |
| contents | We explore the cosmic birefringence signal produced by an ultralight axion field with a small CP-violating coupling to bulk SM matter in addition to the usual CP-preserving photon coupling. The change in the vacuum expectation value of the field between recombination and today results in a frequency-independent rotation of the plane of CMB linear polarization across the entire sky. While many previous approaches rely on the axion rolling from a large initial expectation value, the couplings considered in this work robustly generate the birefringence signal regardless of initial conditions, by sourcing the field from the cosmological nucleon density. We place bounds on such monopole-dipole interactions using measurements of the birefringence angle from Planck and WMAP data, which improve upon existing constraints by up to three orders of magnitude. We also discuss UV completions of this model, and possible strategies to avoid fine-tuning the axion mass. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2311_03536 |
| institution | arXiv |
| publishDate | 2023 |
| record_format | arxiv |
| spellingShingle | Cosmic Birefringence from CP-Violating Axion Interactions Luo, Xuheng Mathur, Anubhav High Energy Physics - Phenomenology Cosmology and Nongalactic Astrophysics High Energy Physics - Theory We explore the cosmic birefringence signal produced by an ultralight axion field with a small CP-violating coupling to bulk SM matter in addition to the usual CP-preserving photon coupling. The change in the vacuum expectation value of the field between recombination and today results in a frequency-independent rotation of the plane of CMB linear polarization across the entire sky. While many previous approaches rely on the axion rolling from a large initial expectation value, the couplings considered in this work robustly generate the birefringence signal regardless of initial conditions, by sourcing the field from the cosmological nucleon density. We place bounds on such monopole-dipole interactions using measurements of the birefringence angle from Planck and WMAP data, which improve upon existing constraints by up to three orders of magnitude. We also discuss UV completions of this model, and possible strategies to avoid fine-tuning the axion mass. |
| title | Cosmic Birefringence from CP-Violating Axion Interactions |
| topic | High Energy Physics - Phenomenology Cosmology and Nongalactic Astrophysics High Energy Physics - Theory |
| url | https://arxiv.org/abs/2311.03536 |