Implications for the non-Gaussianity of curvature perturbation from pulsar timing arrays

Lang Liu; Zu-Cheng Chen; Qing-Guo Huang

doi:10.1103/physrevd.109.l061301

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arXiv · 2307.01102

Implications for the non-Gaussianity of curvature perturbation from pulsar timing arrays

Lang Liu·Zu-Cheng Chen·Qing-Guo Huang

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Abstract

The recently released data by pulsar timing array (PTA) collaborations present strong evidence for a stochastic signal consistent with a gravitational-wave background. Assuming this signal originates from scalar-induced gravitational waves, we jointly use the PTA data from the NANOGrav 15-yr data set, PPTA DR3, and EPTA DR2 to probe the small-scale non-Gaussianity. We put the first-ever constraint on the non-Gaussianity parameter, finding $|F_\mathrm{NL}|\lesssim 13.9$ for a lognormal power spectrum of the curvature perturbations. Furthermore, we obtain $-13.9 \lesssim F_\mathrm{NL}\lesssim -0.1$ to prevent excessive production of primordial black holes. Moreover, the multi-band observations with the space-borne gravitational-wave detectors, such as LISA/Taiji/TianQin, will provide a complementary investigation of primordial non-Gaussianity. Our findings pave the way to constrain inflation models with PTA data.

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Lang Liu, Zu-Cheng Chen, Qing-Guo Huang. 2023-07-03. Implications for the non-Gaussianity of curvature perturbation from pulsar timing arrays. https://doi.org/10.1103/physrevd.109.l061301

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