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arXiv · 2306.17205

Have pulsar timing array methods detected a cosmological phase transition?

Andrea Addazi·Yi-Fu Cai·Antonino Marciano·Luca Visinelli
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Abstract

We show that the recent detection of a gravitational wave (GW) background reported by various pulsar timing array (PTA) collaborations including NANOGrav-15yr, PPTA, EPTA, and CPTA can be explained in terms of first order phase transitions (FOPTs) from dark sector models (DSM). Specifically, we explore a model for first order phase transitions that involves the majoron, a Nambu-Goldstone boson that is emerging from the spontaneous symmetry breaking of a $U(1)_{L}$ or $U(1)_{B-L}$ symmetry. We show how the predicted GW power spectrum, with a realistic choice of the FOPT parameters, is consistent with 1-$\sigma$ deviations from the estimated parameters of the background detected by the PTA collaborations.

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Andrea Addazi, Yi-Fu Cai, Antonino Marciano, Luca Visinelli. 2023-06-29. Have pulsar timing array methods detected a cosmological phase transition?. https://doi.org/10.1103/physrevd.109.015028

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