In this work we present PRyMordial: A package dedicated to efficient computations of
observables in the Early Universe with the focus on the cosmological era of Big Bang …

We revisit the state of the light element abundances from big bang nucleosynthesis in early
2024 with particular focus on the derived baryon abundance. We find that the largest …

Cosmological scenarios with a non-standard equation of state can involve ultrastiff fluids,
understood as primordial fluids for which p/ρ> 1. Their energy densities can dominate the …

Recently, the EMPRESS Collaboration has included new data in the extraction of the
primordial He 4 abundance from big bang nucleosynthesis (BBN), resulting in a …

We argue that the recent result of primordial helium-4 (He 4) abundance measurement by
the EMPRESS Collaboration, which has reported a smaller He 4 abundance than other …

The``neutron lifetime puzzle''arises from the discrepancy between neutron lifetime
measurements obtained using the beam method, which measures decay products, and the …

We explore the big-bang nucleosynthesis (BBN) constraint on heavy neutrino that is a
mixture of gauge singlet fermion and active neutrinos in the Standard Model. We work in the …

This thesis investigates the viability of a long-lived pseudo-Dirac fermion that oscillates
between particle and antiparticle states, enhancing CP-violation to produce the baryon …

The BL3 experiment will be performed to investigate a 4 σ discrepancy between
measurements of the neutron lifetime using a cold neutron beam versus trapped low energy …