Cosmology of the companion-axion model: dark matter, gravitational waves, and primordial black holes

Abstract

The companion-axion model introduces a second QCD axion to rescue the Peccei-Quinn solution to the strong-CP problem from the effects of colored gravitational instantons. As in single-axion models, the two axions predicted by the companion-axion model are attractive candidates for dark matter. The model is defined by two free parameters, the scales of the two axions' symmetry breaking, so we can classify production scenarios in terms of the relative sizes of these two scales with respect to the scale of inflation. We study the cosmological production of companion-axion dark matter in order to predict windows of preferred axion masses, and calculate the relative abundances of the two particles. Additionally, we show that the presence of a second axion solves the cosmological domain wall problem automatically in the scenarios in which one or both of the axions are post-inflationary. We also suggest unique cosmological signatures of the companion-axion model, such as the production of a $\sim$10 nHz gravitational wave background, and $\sim 100M_{\odot }$ primordial black holes.

References in corpus (109)

• SciPy 1.0--Fundamental Algorithms for Scientific Computing in Python
• Array Programming with NumPy
• Observation of Gravitational Waves from a Binary Black Hole Merger
• Planck 2018 results. X. Constraints on inflation
• Axion Cosmology
• String Axiverse
• Axions In String Theory
• Laser Interferometer Space Antenna
• Constraints on Primordial Black Holes
• The Low-Energy Frontier of Particle Physics
• The NANOGrav 12.5-year Data Set: Search For An Isotropic Stochastic Gravitational-Wave Background
• Gravitational-wave sensitivity curves
• A SQUID-based microwave cavity search for dark-matter axions
• Primordial Black Holes as a dark matter candidate
• A Search for Invisible Axion Dark Matter with the Axion Dark Matter Experiment
• Sensitivity curves for searches for gravitational-wave backgrounds
• Completing Natural Inflation
• European Pulsar Timing Array Limits On An Isotropic Stochastic Gravitational-Wave Background
• N-flation
• The type IIB string axiverse and its low-energy phenomenology
• The Parkes Pulsar Timing Array Project
• Gravitational waves from binary supermassive black holes missing in pulsar observations
• Extended Search for the Invisible Axion with the Axion Dark Matter Experiment
• The North American Nanohertz Observatory for Gravitational Waves
• Dielectric Haloscopes: A New Way to Detect Axion Dark Matter
• The NANOGrav 11-year Data Set: Pulsar-timing Constraints On The Stochastic Gravitational-wave Background
• Axion Cosmology
• Fundamental Physics with the Square Kilometre Array
• Science with the Square Kilometer Array: Motivation, Key Science Projects, Standards and Assumptions
• Broadband and Resonant Approaches to Axion Dark Matter Detection
• Axion dark matter from topological defects
• The ORGAN Experiment: An axion haloscope above 15 GHz
• Axion Cosmology Revisited
• New Sensitivity Curves for Gravitational-Wave Signals from Cosmological Phase Transitions
• The QCD Running Coupling
• First Results from ABRACADABRA-10 cm: A Search for Sub-$\mu$eV Axion Dark Matter
• Axions from Strings: the Attractive Solution
• More Axions from Strings
• Search for "Invisible" Axion Dark Matter in the $3.3\text{-}4.2\mu$eV Mass Range
• European Pulsar Timing Array Limits on Continuous Gravitational Waves from Individual Supermassive Black Hole Binaries
• Early-Universe Simulations of the Cosmological Axion
• Tunable axion plasma haloscopes
• Dark Matter from Axion Strings with Adaptive Mesh Refinement
• Dark Matter Axions Revisited
• Early seeds of axion miniclusters
• The dark-matter axion mass
• Axion and hidden photon dark matter detection with multilayer optical haloscopes
• On the estimation of gravitational wave spectrum from cosmic domain walls
• Solar-Mass Primordial Black Holes Explain NANOGrav Hint of Gravitational Waves
• A review of gravitational waves from cosmic domain walls
• An M Theory Solution to the Strong CP Problem and Constraints on the Axiverse
• On a Light Spinless Particle Coupled to Photons
• The search for low-mass axion dark matter with ABRACADABRA-10cm
• Axion cosmology with long-lived domain walls
• The NANOGrav 11-Year Data Set: Limits on Gravitational Waves from Individual Supermassive Black Hole Binaries
• Piezoelectrically Tuned Multimode Cavity Search for Axion Dark Matter
• Search for axion-like dark matter with ferromagnets
• Update of axion CDM energy density
• Isocurvature bounds on axions revisited
• ADMX SLIC: Results from a Superconducting LC Circuit Investigating Cold Axions
• Gravitational Waves from Collapsing Domain Walls
• Gravitational Waves from Supercool Axions
• Axion dark matter: strings and their cores
• Gravity and Domain Wall Problem
• Axion dark matter in the post-inflationary Peccei-Quinn symmetry breaking scenario
• IS THERE A DOMAIN WALL PROBLEM?
• Axion Searches with Microwave Filters: the RADES project
• The Cosmic Axion Background
• Bounds on isocurvature perturbations from CMB and LSS data
• Bayesian model selection and isocurvature perturbations
• Peccei-Quinn Phase Transition at LIGO
• Primordial Black Holes from the QCD axion
• Solar axions cannot explain the XENON1T excess
• Experimental Targets for Photon Couplings of the QCD Axion
• Axion Quasiparticles for Axion Dark Matter Detection
• Gravitational wave probes of axion-like particles
• Concept of multiple-cell cavity for axion dark matter search
• Study of gravitational radiation from cosmic domain walls
• Searching for axions and ALPs from string theory
• Isocurvature Constraints and Anharmonic Effects on QCD Axion Dark Matter
• Constraints on the Coupling between Axionlike Dark Matter and Photons Using an Antiproton Superconducting Tuned Detection Circuit in a Cryogenic Penning Trap
• The Spectrum of the Axion Dark Sector
• Eliminating the LIGO bounds on primordial black hole dark matter
• Gravitational waves from axion-like particle cosmic string-wall networks
• Resonant conversions of QCD axions into hidden axions and suppressed isocurvature perturbations
• Dynamical Axions and Gravitational Waves
• New confining force solution of QCD axion domain wall problem
• Astrometric Limits on the Stochastic Gravitational Wave Background
• Anharmonic Evolution of the Cosmic Axion Density Spectrum
• The NANOGrav Program for Gravitational Waves and Fundamental Physics
• Axions and Axion-like Particles
• Friendship in the Axiverse: Late-time direct and astrophysical signatures of early-time nonlinear axion dynamics
• Cosmic implications of a low-scale solution to the axion domain wall problem
• Biased discrete symmetry and domain wall problem
• Hidden axion dark matter decaying through mixing with QCD axion and the 3.5 keV X-ray line
• Axion Dissipation Through the Mixing of Goldstone Bosons
• Cosmological Tension of Ultralight Axion Dark Matter and its Solutions
• Axion global fits with Peccei-Quinn symmetry breaking before inflation using GAMBIT
• The Stochastic Axiverse
• The KLASH Proposal
• On the high-scale instanton interference effect: axion models without domain wall problem
• Semiclassical Gravity and Invisible Axions
• Axion-like particle oscillations
• Coloured gravitational instantons, the strong CP problem and the companion axion solution
• Phenomenology of the companion-axion model: photon couplings
• Axions from wall decay
• Charged gravitational instantons: extra CP violation and charge quantisation in the Standard Model
• Lunar Mass Black Holes from QCD Axion Cosmology
• A Tale of Two-U(1) Axion Models