Prospects for searching for sterile neutrinos with gravitational wave and <i>γ</i>-ray burst joint observations

Abstract Sterile neutrinos can influence the evolution of the Universe, and thus cosmological observations can be used to detect them. Future gravitational-wave (GW) observations can precisely measure absolute cosmological distances, helping to break parameter degeneracies generated by traditional cosmological observations. This advancement can lead to much tighter constraints on sterile neutrino parameters. This work provides a preliminary forecast for detecting sterile neutrinos using third-generation GW detectors in combination with future short γ -ray burst observations from a THESEUS-like telescope, an approach not previously explored in the literature. Both massless and massive sterile neutrinos are considered within the ΛCDM cosmology. We find that using GW data can greatly enhance the detection capability for massless sterile neutrinos, reaching 3 σ level. For massive sterile neutrinos, GW data can also greatly assist in improving the parameter constraints, but it seems that effective detection is still not feasible.