English

Neutrinophilic $\mathbf{\Lambda}$CDM Extension for EMPRESS, DESI and Hubble Tension

High Energy Physics - Phenomenology 2025-01-24 v1 Cosmology and Nongalactic Astrophysics

Abstract

A number of recent cosmological observations have indicated the presence of new physics beyond the Λ\mathbf{\Lambda}CDM 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 Λ\mathbf{\Lambda}CDM model with primordial neutrino asymmetry ξν\xi_{\nu} and additional contribution to the effective number of neutrinos δNeff\delta N_{\rm eff}. 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 NeffN_{\rm eff}. Comparing different extensions of the Λ\mathbf{\Lambda}CDM model, we show that the neutrinophilic Λ\mathbf{\Lambda}CDM extension with ξν=0.056±0.017\xi_{\nu} = 0.056 \pm 0.017 and δNeff=0.41±0.16\delta N_{\rm eff} = 0.41 \pm 0.16 is preferred by current observations, while the Hubble tension in this model is also alleviated to be 2.2σ2.2 \sigma.

Keywords

Cite

@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}
}

Comments

7 pages, 4 figures, and 1 table

R2 v1 2026-06-28T21:14:03.404Z