A number of recent cosmological observations have indicated the presence of new physics beyond the ΛCDM model. Combining observations from EMPRESS on helium abundance and DESI on baryon acoustic oscillations with Hubble tension, we show that all of them can be explained concurrently with a extension of the ΛCDM model with primordial neutrino asymmetry ξν and additional contribution to the effective number of neutrinos δNeff. Based on the accurate treatments of neutrino decoupling and BBN processes, we present state-of-the-art constraints on neutrino asymmetry for the fixed or varying Neff. Comparing different extensions of the ΛCDM model, we show that the neutrinophilic ΛCDM extension with ξν=0.056±0.017 and δNeff=0.41±0.16 is preferred by current observations, while the Hubble tension in this model is also alleviated to be 2.2σ.
@article{arxiv.2501.13153,
title = {Neutrinophilic $\mathbf{\Lambda}$CDM Extension for EMPRESS, DESI and Hubble Tension},
author = {Yuan-Zhen Li and Jiang-Hao Yu},
journal= {arXiv preprint arXiv:2501.13153},
year = {2025}
}