Speaker
Description
We study the impact of an early dark energy component (EDE) present during big bang nucleosynthesis (BBN) on the elemental abundances of deuterium (D/H), and helium ($Y_p$), as well as the effective relativistic degrees of freedom $N_{\rm eff}$. We consider a simple model of EDE that is constant up to a critical temperature. After the critical temperature, the EDE decays as either standard model photons that mix with the plasma, dark photons that are uncoupled, or kination. We use measured values of the abundances and $N_{\rm eff}$ to establish limits on the input parameters of this EDE model, namely the amount of EDE initially present ($\rho_{\Lambda}$), and the critical temperature ($T_{\rm crit}$). In addition, we explore how those parameters are correlated with BBN inputs; the baryon to photon ratio $\eta_b$, neutron lifetime $\tau_n$, and number of neutrinos $N_\nu$.
