| Article | |
| Report number | arXiv:2306.17136 ; CERN-TH-2023-080 |
| Title | Footprints of the QCD Crossover on Cosmological Gravitational Waves at Pulsar Timing Arrays |
| Related title | Erratum: Footprints of the QCD Crossover on Cosmological Gravitational Waves at Pulsar Timing Arrays [Phys. Rev. Lett. 132, 081001 (2024)] |
| Author(s) | Franciolini, Gabriele (Rome U.) ; Racco, Davide (Stanford U., ITP) ; Rompineve, Fabrizio (CERN ; Barcelona, IFAE ; BIST, Barcelona ; Barcelona, Autonoma U.) |
| Publication | 2024-02-20 |
| Imprint | 2023-06-29 |
| Number of pages | 9 |
| Note | 5+11 pages, 7 figures. v2: Analysis with NANOGrav 15 yrs added, minor corresponding changes in abstract and text, references added. v3: fixed numerical calculation of the causality tail, updated Table II and figures, improved discussion in Sec. II |
| In: | Phys. Rev. Lett. |
| DOI | 10.1103/PhysRevLett.132.081001 (publication) 10.1103/PhysRevLett.133.189901 (erratum) |
| Subject category | hep-ph ; Particle Physics - Phenomenology ; hep-lat ; Particle Physics - Lattice ; gr-qc ; General Relativity and Cosmology ; astro-ph.HE ; Astrophysics and Astronomy ; astro-ph.CO ; Astrophysics and Astronomy |
| Abstract | Pulsar Timing Arrays (PTAs) have reported evidence for a stochastic gravitational wave (GW) background at nHz frequencies, possibly originating in the early Universe. We show that the spectral shape of the low-frequency (causality) tail of GW signals sourced at temperatures around $T\gtrsim 1$ GeV is distinctively affected by confinement of strong interactions (QCD), due to the corresponding sharp decrease in the number of relativistic species. Bayesian analyses in the NANOGrav 15 years and the previous International PTA datasets reveal a significant improvement in the fit with respect to cubic power-law spectra, previously employed for the causality tail. This suggests that the inclusion of Standard Model effects on GWs can have a potentially decisive impact on model selection. |
| Copyright/License | preprint: (License: arXiv nonexclusive-distrib 1.0) publication: © 2024 authors (License: CC BY 4.0) |
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Záznam vytvorený 2023-07-01, zmenený 2024-11-13