Cosmic birefringence and electroweak axion dark energy

Gongjun Choi,Tsutomu T Yanagida,Weikang Lin,Luca Visinelli

doi:10.1103/physrevd.104.l101302

Abstract

Taking the recently reported non-zero rotation angle of the cosmic microwave background (CMB) linear polarization $\beta=0.35\pm0.14{\rm\, deg}$ as the hint for a pseudo Nambu-Goldstone boson quintessence dark energy (DE), we study the electroweak (EW) axion quintessence DE model where the axion mass is generated by the EW instantons. We find that the observed value of $\beta$ implies a non-trivial $U(1)$ electromagnetic anomaly coefficient ($c_{\gamma}$), once the current constraint on the DE equation of state is also taken into account. With the aid of the hypothetical high energy structure of the model inspired by the experimentally inferred $c_{\gamma}$, the model is shown to be able to make prediction for the current equation of state ($w_{\rm DE,0}$) of the quintessence DE. This is expected to make our scenario distinguishable in comparison with the cosmological constant ($w=-1$) and testable in future when the error in the future measurement of $w_{\rm DE,0}$ is reduced to $\mathcal{O}(1)\%$ level ($\delta w=\mathcal{O}(10^{-2})$).

Highlights

The recently reported nonvanishing rotation angle β 1⁄4 Oð0.1Þ deg of the cosmic microwave background (CMB) linear polarization [1] (a.k.a. cosmic birefringence) may serve as a crucial hint for the presence of new physics beyond the Standard Model (SM), pointing at a source for parity violation in Nature other than weak interactions
Taking the recently reported nonzero rotation angle of the cosmic microwave background (CMB) linear polarization β 1⁄4 0.35 Æ 0.14 deg as the hint for a pseudo–Nambu-Goldstone boson quintessence dark energy (DE), we study the electroweak (EW) axion quintessence DE model where the axion mass is generated by the EW instantons
We find that the observed value of β implies a nontrivial Uð1Þ electromagnetic anomaly coefficient, once the current constraint on the DE equation of state is taken into account

Summary

INTRODUCTION

The recently reported nonvanishing rotation angle β 1⁄4 Oð0.1Þ deg of the cosmic microwave background (CMB) linear polarization [1] (a.k.a. cosmic birefringence) may serve as a crucial hint for the presence of new physics beyond the Standard Model (SM), pointing at a source for parity violation in Nature other than weak interactions. Associated with a spontaneously broken global Uð1ÞX symmetry [10,11,12,13] In this case, the equation of state (EoS) of φ (wφ ≡ Pφ=ρφ) is expected to lie in the range −1 ≤ wφ ≲ 0, where Pφ and ρφ are the pressure and energy density of φ respectively. The field φ can be identified with a candidate of the quintessence dark energy (QDE) characterized by the EoS today wDE;0. Is it possible to realize a well-motivated and consistent. SUð2Þ instantons with ρ ∼ M−P1 in the minimal supersymmetric extension of the SM (MSSM) can generate the axion potential comparable to the present energy density of DE This led to the first proposal of the EW axion QDE model [12].

EW AXION DE MODEL

EW AXION DE PHENOMENOLOGY

CONCLUSIONS