Cosmological search for sterile neutrinos after DESI 2024

Abstract The question of whether massive sterile neutrinos exist remains a crucial unresolved issue in both particle physics and cosmology. We explore the cosmological constraints on massive sterile neutrinos using the latest observational data, including the baryon acoustic oscillations data from the Dark Energy Spectroscopic Instrument (DESI), the cosmic microwave background data from the Planck satellite and Atacama Cosmology Telescope (ACT), and the 5-year Type Ia supernova data and 3-year weak-lensing data from the Dark Energy Survey (DES). We search for massive sterile neutrinos within the $$\Lambda $$ Λ CDM, w CDM, and $$w_0w_a$$ w 0 w a CDM models. Our analysis shows that when considering massive sterile neutrinos within the $$w_0w_a\mathrm CDM$$ w 0 w a C D M model, the combined datasets allow us to infer a nonzero sterile neutrino mass at an approximately $$2\sigma $$ 2 σ confidence level. Specifically, in the $$w_0w_a$$ w 0 w a CDM+Sterile model, the effective mass of sterile neutrinos and the effective number of relativistic species are constrained to $$m_{\nu ,\ \textrm{sterile}}^{\textrm{eff}} = 0.50^{+0.33}_{-0.27} \, \textrm{eV}$$ m ν , sterile eff = 0 . 50 - 0.27 + 0.33 eV and $$N_\textrm{eff} = 3.076^{+0.011}_{-0.017}$$ N eff = 3 . 076 - 0.017 + 0.011 , respectively. However, the $$\Lambda $$ Λ CDM+Sterile and w CDM+Sterile models could not provide evidence supporting the existence of massive sterile neutrinos.