We have taken a comprehensive approach to update the limits on the tensor-to-scalar ratio (r) and the tensor spectral index (nt), using 10 datasets from the BICEP/Keck Array 2015 and 2018, Planck releases 3 and 4, and LIGO-Virgo-KAGRA Collaboration. By fitting the complete ΛCDM+r+nt model with two different approaches for the tensor sector, we have not only established which method is the most reliable, but have also achieved the strongest constraint on the tensor-to-scalar ratio in current literature: r < 0.028 and -1.37 < nt < 0.42 at 95% confidence level. Furthermore, our examination of the common signal detected by the NANOGrav Collaboration further confirms that a simple power-law cannot reconcile the constraints from different datasets if the NANOGrav detection is due to a primordial inflationary gravitational wave background, as previously shown in the literature.

Updated constraints on amplitude and tilt of the tensor primordial spectrum / Galloni, Giacomo; Bartolo, Nicola; Matarrese, Sabino; Migliaccio, Marina; Ricciardone, Angelo; Vittorio, Nicola. - In: JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS. - ISSN 1475-7516. - 4:(2023), pp. 1-31. [10.1088/1475-7516/2023/04/062]

Updated constraints on amplitude and tilt of the tensor primordial spectrum

Galloni, Giacomo
Primo
;
Matarrese, Sabino;
2023

Abstract

We have taken a comprehensive approach to update the limits on the tensor-to-scalar ratio (r) and the tensor spectral index (nt), using 10 datasets from the BICEP/Keck Array 2015 and 2018, Planck releases 3 and 4, and LIGO-Virgo-KAGRA Collaboration. By fitting the complete ΛCDM+r+nt model with two different approaches for the tensor sector, we have not only established which method is the most reliable, but have also achieved the strongest constraint on the tensor-to-scalar ratio in current literature: r < 0.028 and -1.37 < nt < 0.42 at 95% confidence level. Furthermore, our examination of the common signal detected by the NANOGrav Collaboration further confirms that a simple power-law cannot reconcile the constraints from different datasets if the NANOGrav detection is due to a primordial inflationary gravitational wave background, as previously shown in the literature.
2023
Bayesian reasoning; CMBR experiments; gravitational wave detectors; inflation
01 Pubblicazione su rivista::01a Articolo in rivista
Updated constraints on amplitude and tilt of the tensor primordial spectrum / Galloni, Giacomo; Bartolo, Nicola; Matarrese, Sabino; Migliaccio, Marina; Ricciardone, Angelo; Vittorio, Nicola. - In: JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS. - ISSN 1475-7516. - 4:(2023), pp. 1-31. [10.1088/1475-7516/2023/04/062]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11573/1691099
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