Nuclear Processes in Other Universes: Varying the Strength of the Weak Force

Understand

Motivated by the possibility that the laws of physics could be different in other regions of space-time, we consider nuclear processes in universes where the weak interaction is either stronger or weaker than observed.

• We focus on the physics of both Big Bang Nucleosynthesis (BBN) and stellar evolution.
• For sufficiently ineffective weak interactions, neutrons do not decay during BBN, and the baryon-to-photon ratio $\eta$ must be smaller in order for protons to survive without becoming incorporated into larger nuclei.
• For stronger weak interactions, neutrons decay before the onset of BBN, and the early universe is left with nearly a pure hydrogen composition.