Unveiling the Graviton Mass Bounds through Analysis of 2023 Pulsar Timing Array Data Releases

Understand

Strong evidence for the Helling-Downs correlation curves have been reported by multiple pulsar timing array (PTA) collaborations in middle 2023.

• In this work, we investigate the graviton mass bounds by analyzing the observational data of the overlap ruduction functions from the NANOGrav 15-year data release and CPTA first data release.
• The results from our data analysis display the state-of-the-art upper limits on the graviton mass at 90\% confidence level, namely, $m_{g}\lesssim8.6\times10^{-24}\mathrm{eV}$ from NANOGrav and $m_{g}\lesssim3.8\times10^{-23}\mathrm{eV}$ from CPTA.
• We also study the cosmic-variance limit on the graviton mass bounds, i.e., $\sigma_{m_{g}}^{\mathrm{CV}}=4.8\times10^{-24}\mathrm{eV}\times f/(10~\mathrm{year})^{-1}$, with $f$ being a typical frequency band of PTA observations.