Axion-Gauge Dynamics During Inflation as the Origin of Pulsar Timing Array Signals and Primordial Black Holes

Abstract

We demonstrate that the recently announced signal for a stochastic gravitational wave background (SGWB) from pulsar timing array (PTA) observations, if attributed to new physics, is compatible with primordial GW production due to axion-gauge dynamics during inflation. More specifically we find that axion-$U(1)$ models may lead to sufficient particle production to explain the signal while simultaneously source some fraction of sub-solar mass primordial black holes (PBHs) as a signature. Moreover there is a parity violation in GW sector, hence the model suggests chiral GW search as a concrete target for future. We further analyze the axion-$SU(2)$ coupling signatures and find that in the low/mild backreaction regime, it is incapable of producing PTA evidence and the tensor-to-scalar ratio is low at the peak, hence it overproduces scalar perturbations and PBHs.

2 figures, total 8 pages, published in PLB

References in corpus (7)

• The NANOGrav 15-year Data Set: Search for Signals from New Physics
• Sensitivity to a Frequency-Dependent Circular Polarization in an Isotropic Stochastic Gravitational Wave Background
• Massive black hole binary systems and the NANOGrav 12.5 year results
• Bayesian Implications for the Primordial Black Holes from NANOGrav's Pulsar-Timing Data Using the Scalar-Induced Gravitational Waves
• Oscillating Chiral Tensor Spectrum from Axionic Inflation
• Chirality of the gravitational-wave background and pulsar-timing arrays
• Low temperature electroweak phase transition in the Standard Model with hidden scale invariance

Cited by in corpus (21)

• Inflationary Butterfly Effect: Non-perturbative Dynamics From Small-Scale Features
• Induced Gravitational Wave interpretation of PTA data: a complete study for general equation of state
• Enhancement of gravitational waves at Q-ball decay including non-linear density perturbations
• LiteBIRD Science Goals and Forecasts. A Case Study of the Origin of Primordial Gravitational Waves using Large-Scale CMB Polarization
• Unveiling the nonlinear dynamics of a rolling axion during inflation
• Gauge preheating with full general relativity
• Can we distinguish the adiabatic fluctuations and isocurvature fluctuations with pulsar timing arrays?
• Parity-violating scalar trispectrum from a rolling axion during inflation
• Constraining the history of reheating with the NANOGrav 15-year data
• Fast Likelihood-free Reconstruction of Gravitational Wave Backgrounds
• Chromo-natural inflation supported by enhanced friction from Horndeski gravity
• Dark Matter Spike surrounding Supermassive Black Holes Binary and the Nanohertz Stochastic Gravitational Wave Background
• Implications for Pulsar Timing Arrays of Sub-solar Black Hole Detections: From LVK to Einstein Telescope and Cosmic Explorer
• Strong backreaction of gauge quanta produced during inflation
• Gravitational waves from axion inflation in the gradient expansion formalism. Part I. Pure axion inflation
• On the prospects of thermalization of axion-SU(2) inflation
• Perturbative limits on axion-SU(2) gauge dynamics during inflation from the energy density of spin-2 particles
• Gravitational Waves from a Gauge Field Non-minimally Coupled to Gravity
• Purely quadratic non-Gaussianity from tachyonic instability: Primordial black holes and scalar-induced gravitational waves
• Testing No slip model with pulsar timing arrays: NANOGrav and IPTA
• Gravitational Waves from Gauge Quanta Produced during Inflation