Searching for axionlike time-dependent cosmic birefringence with data from SPT-3G

• Published in: Physical Review D
• Main Authors: Ferguson, R. K., SPT-3G Collaboration, Tucker, Carole
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: 2022
• Subjects: South Pole; South pole
• Online Access: https://orca.cardiff.ac.uk/id/eprint/156650/; https://doi.org/10.1103/PhysRevD.106.042011

Ultralight axionlike particles (ALPs) are compelling dark matter candidates because of their potential to resolve small-scale discrepancies between Λ CDM predictions and cosmological observations. Axion-photon coupling induces a polarization rotation in linearly polarized photons traveling through an ALP field; thus, as the local ALP dark matter field oscillates in time, distant static polarized sources will appear to oscillate with a frequency proportional to the ALP mass. We use observations of the cosmic microwave background from SPT-3G, the current receiver on the South Pole Telescope, to set upper limits on the value of the axion-photon coupling constant g ϕ γ over the approximate mass range 10 -22 - 10 -19 eV , corresponding to oscillation periods from 12 hours to 100 days. For periods between 1 and 100 days (4.7 ×10 -22 eV ≤m ϕ ≤4.7 ×10 -20 eV ), where the limit is approximately constant, we set a median 95% C.L. upper limit on the amplitude of on-sky polarization rotation of 0.071 deg. Assuming that dark matter comprises a single ALP species with a local dark matter density of 0.3 GeV /cm 3 , this corresponds to g ϕ γ <1.18 ×10 -12 GeV -1 ×(m/ ϕ 1.0 ×10 -21 eV ) . These new limits represent an improvement over the previous strongest limits set using the same effect by a factor of ∼3.8 .