Improved big bang nucleosynthesis constraints on heavy neutral leptons

Boiarskyi, O.; Ovchynnikov, M.; Ruchayskiy, O.; Syvolap, V. (2021)

Article / Letter to editor

We constrain the lifetime of thermally produced heavy neutral leptons (HNLs) from big bang nucleosynthesis. We show that even a small fraction of mesons present in the primeval plasma leads to the overproduction of primordial helium-4. This constrains the lifetime of HNLs to be tau(N) < 0.02 s for masses above the mass of the pion (as compared to 0.1 s reported previously). In combination with accelerator searches, this allows us to put a new lower bound on the HNL masses and define the "bottom line" for HNL searches at the future Intensity Frontier experiments.

• All authors: Boiarskyi, O.; Ovchynnikov, M.; Ruchayskiy, O.; Syvolap, V.
• Date: 2021-07-16
• Journal: Physical Review D
• Volume: 104
• Issue: 2
• DOI: doi:10.1103/PhysRevD.104.023517