TY - JOUR

T1 - Probing axionlike particles via cosmic microwave background polarization

AU - Fujita, Tomohiro

AU - Minami, Yuto

AU - Murai, Kai

AU - Nakatsuka, Hiromasa

N1 - Funding Information:
We would like to thank Ricardo Z. Ferreira, Masahiro Ibe, Masahiro Kawasaki, Eiichiro Komatsu, Ippei Obata, So Okano, Günter Sigl, and Pranjal Trivedi for fruitful discussions and productive comments. K. M. was supported by World Premier International Research Center Initiative (WPI Initiative), MEXT, Japan and the Program of Excellence in Photon Science. H. N. was supported by Advanced Leading Graduate Course for Photon Science. This work was supported in part by the Japan Society for the Promotion of Science (JSPS) KAKENHI, Grant Number JP18K13537, JP19J21974, JP20K14497, and JP20J20248.
Publisher Copyright:
© 2021 American Physical Society.

PY - 2021/3/10

Y1 - 2021/3/10

N2 - Axionlike particles (ALPs) rotate the linear polarization of photons through the ALP-photon coupling and convert the cosmic microwave background (CMB) E mode to the B mode. We derive the relation between the ALP dynamics and the rotation angle by assuming that the ALP φ has a quadratic potential, V=m2φ2/2. We compute the current and future sensitivities of CMB observations to the ALP-photon coupling g, which can reach g=4×10-21 GeV-1 for 10-32 eV≲m≲10-28 eV and extensively exceed the other searches for any mass m≲10-25 eV. We find that the fluctuation of the ALP field at the observer, which has been neglected in previous studies, can induce significant isotropic rotation of the CMB polarization. The measurements of isotropic and anisotropic rotation allow us to put bounds on relevant quantities, such as the ALP mass m and the ALP density parameter ωφ. In particular, if LiteBIRD detects anisotropic rotation, we obtain the lower bound on the tensor-to-scalar ratio as r>5×10-9.

AB - Axionlike particles (ALPs) rotate the linear polarization of photons through the ALP-photon coupling and convert the cosmic microwave background (CMB) E mode to the B mode. We derive the relation between the ALP dynamics and the rotation angle by assuming that the ALP φ has a quadratic potential, V=m2φ2/2. We compute the current and future sensitivities of CMB observations to the ALP-photon coupling g, which can reach g=4×10-21 GeV-1 for 10-32 eV≲m≲10-28 eV and extensively exceed the other searches for any mass m≲10-25 eV. We find that the fluctuation of the ALP field at the observer, which has been neglected in previous studies, can induce significant isotropic rotation of the CMB polarization. The measurements of isotropic and anisotropic rotation allow us to put bounds on relevant quantities, such as the ALP mass m and the ALP density parameter ωφ. In particular, if LiteBIRD detects anisotropic rotation, we obtain the lower bound on the tensor-to-scalar ratio as r>5×10-9.

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U2 - 10.1103/PhysRevD.103.063508

DO - 10.1103/PhysRevD.103.063508

M3 - Article

AN - SCOPUS:85103080050

VL - 103

JO - Physical Review D

JF - Physical Review D

SN - 2470-0010

IS - 6

M1 - 063508

ER -