Quark mass variation constraints from Big Bang nucleosynthesis

Understand

We study the impact on the primordial abundances of light elements created by a variation of the quark masses at the time of Big Bang nucleosynthesis (BBN).

• In order to navigate through the particle and nuclear physics required to connect quark masses to binding energies and reaction rates in a model-independent way, we use lattice QCD data and a hierarchy of effective field theories.
• We find that the measured Helium-4 abundances put a bound of -1 % <~ d m_q/m_q <~ 0.7 % on a possible variation of quark masses.
• The effect of quark mass variations on the deuterium abundances can be largely compensated by changes of the baryon-to-photon ratio eta.