Constraining cosmological phase transitions with the Parkes Pulsar Timing Array by Xiao Xue et al. on Monday 28 November

A cosmological first-order phase transition is expected to produce a

stochastic gravitational wave background. If the phase transition temperature

is on the MeV scale, the power spectrum of the induced stochastic gravitational

waves peaks around nanohertz frequencies, and can thus be probed with

high-precision pulsar timing observations. We search for such a stochastic

gravitational wave background with the latest data set of the Parkes Pulsar

Timing Array. We find no evidence for a Hellings-Downs spatial correlation as

expected for a stochastic gravitational wave background. Therefore, we present

constraints on first-order phase transition model parameters. Our analysis

shows that pulsar timing is particularly sensitive to the low-temperature ($T

\sim 1 - 100$ MeV) phase transition with a duration $(\beta/H_*)^{-1}\sim

10^{-2}-10^{-1}$ and therefore can be used to constrain the dark and QCD phase

transitions.

arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2110.03096v2