Quark-mass dependence of compound-nucleus excited states

Determine how compound-nucleus excited-state energies respond to changes in the averaged light-quark mass induced by a varying Higgs vacuum expectation value, in order to establish the corresponding shifts of Big Bang nucleosynthesis resonance energies and reaction rates.

Background

The paper models the effects of a varying Higgs vacuum expectation value on Big Bang nucleosynthesis by allowing quark masses, nuclear binding energies, reaction Q-values, and resonance energies to change. Three resonant reactions—^3H(d,n)^4He, ^3He(d,p)^4He, and ^7Be(n,p)^7Li—are identified as particularly important for primordial deuterium and ^7Li abundances.

The authors note that the energy of a compound-nucleus excited state may not shift in the same way as the ground-state binding energy when the quark mass changes. Because the assumed resonance-energy response substantially affects calculated reaction rates and abundance constraints, they investigate three phenomenological scenarios, including common shifts, a reverse-reaction-strength condition, and a fixed resonance energy. A microscopic determination of the excited-state response remains unresolved.