6533b85bfe1ef96bd12bb619
RESEARCH PRODUCT
Whispers from the dark side: Confronting light new physics with NANOGrav data
Pedro SchwallerWolfram Ratzingersubject
PhysicsCosmology and Nongalactic Astrophysics (astro-ph.CO)010308 nuclear & particles physicsPhysicsQC1-999Physics beyond the Standard Modelmedia_common.quotation_subjectGeneral Physics and AstronomyFOS: Physical sciencesAstrophysicsParameter space01 natural sciencesSpectral lineUniverseGravitational wave backgroundHigh Energy Physics - PhenomenologyHigh Energy Physics - Phenomenology (hep-ph)Pulsar0103 physical sciencesExponential decay010306 general physicsAxionAstrophysics - Cosmology and Nongalactic Astrophysicsmedia_commondescription
The NANOGrav collaboration has recently observed first evidence of a gravitational wave background (GWB) in pulsar timing data. Here we explore the possibility that this GWB is due to new physics, and show that the signal can be well fit also with peaked spectra like the ones expected from phase transitions (PTs) or from the dynamics of axion like particles (ALPs) in the early universe. We find that a good fit to the data is obtained for a very strong PT at temperatures around 1 MeV to 10 MeV. For the ALP explanation the best fit is obtained for a decay constant of $F \approx 5\times 10^{17}$ GeV and an axion mass of $2\times 10^{-13}$ eV. We also illustrate the ability of PTAs to constrain the parameter space of these models, and obtain limits which are already comparable to other cosmological bounds.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2021-02-01 |