Cosmic Superstrings Revisited in Light of NANOGrav 15-Year Data

Abstract

We analyze cosmic superstring models in light of NANOGrav 15-year pulsar timing data. A good fit is found for a string tension $G\mu \sim 10^{-12}-10^{-11}$ and a string intercommutation probability $p\sim 10^{-3}-10^{-1}$. Extrapolation to higher frequencies assuming standard Big Bang cosmology is compatible at the 68\% CL with the current LIGO/Virgo/KAGRA upper limit on a stochastic gravitational wave background in the 10 to 100 Hz range. The superstring interpretation of the NANOGrav data would be robustly testable by future experiments even in modified cosmological scenarios.

Comments: 7 pages 4 figures. Typos fixed and new references added