Large-scale simulations of quarks promise precise view of reactions of astrophysical importance

The fusion of two protons initiates the primary nuclear cycle that powers the Sun. The rate of this low-energy, weak-interaction fusion is too small to be measured in the laboratory. While nuclear model predictions for this reaction are impressive, calculations without models would reduce uncertainties and offer a more accurate view of proton-proton fusion and related processes. Using a technique called lattice quantum chromodynamics, scientists performed the first successful model-independent calculation of the proton-proton fusion rate directly from the fundamental dynamics of quarks and gluons (the building blocks of protons and nuclei).