Visible in the laboratory and invisible in cosmology: decaying sterile neutrinos

• DOI: 10.48550/arxiv.2309.11492
• Publication Date: 2023-01-01
• Authors: Kevork N. Abazajian; Helena García Esc...
• Keywords: Big Bang nucleosynthesis

The expansion history and thermal physical process that happened in the early Universe before big bang nucleosynthesis (BBN) remains relatively unconstrained by observations. Low reheating temperature universes with normalcy temperatures of $T_\mathrm{RH}\sim 2\,\mathrm{MeV}$ remain consistent primordial nucleosynthesis, accommodate several new physics scenarios would normally be constrained high-temperature models, including massive sterile neutrinos. We explore such scenarios' production keV scale neutrinos their resulting constraints from cosmological parameter space for is much less than high-$T_\mathrm{RH}$ histories, though remain. Such target current upcoming laboratory experiments as TRISTAN (KATRIN), HUNTER, MAGNETO-$\nu$, PTOLEMY. Cosmological stringent stable keV-scale However, we show a dark decay to radiation through $Z^\prime$ or scalar are largely cosmology. In addition, this mechanism large mixing may provide solution Hubble tension. find therefore one best probes untested pre-BBN era could seen experiments.