Importance of Shot Noise in the Search for an Isotropic Stochastic Gravitational-Wave Background with Next Generation Detectors

The stochastic gravitational-wave background (SGWB) from binary neutron star (BNS) mergers encodes rich information about compact binary populations and cosmic evolution. However, its measurement can be strongly affected by shot noise, where a few nearby, loud events dominate the signal. In this talk, I will present a systematic study of how shot noise biases SGWB measurements and how this effect can be effectively mitigated. I will introduce a time–frequency notching procedure that removes resolvable nearby events and demonstrate that it suppresses shot noise while preserving the true background signal. I will also discuss how the resulting sample variance and cross-correlation bias influence the detectability of the SGWB. Remarkably, we find that the overall sensitivity loss is minimal—limited to ≲ 4% below 40 Hz and ≲ 1% above 40 Hz—showing that the notching approach provides a robust path toward accurate SGWB measurements in upcoming observing runs.