Argon-36 Outshines Argon-40 in Single-Bubble Sonoluminescence: A Pre-Registered Prediction

I record, with its lock date, a prediction made before any measurement was consulted: in single-bubble sonoluminescence (SBSL), a bubble of argon-36 will emit more light per flash than a bubble of argon-40 under matched conditions. The prediction follows from a conjecture in the Viscoelastic Vacuum Model (VVM), in which a closed-shell atom whose nucleus holds equal numbers of protons and neutrons is a balanced resonator of the vacuum medium. Conventional bubble physics points the other way: the lighter isotope conducts heat away from the collapse about five per cent faster, which would make it equal or slightly dimmer. Because the two accounts predict opposite signs, a single matched comparison decides between them. Isotope effects in SBSL are established for hydrogen and deuterium, but no comparison of the argon isotopes has been found in the literature. I state the prediction, its pass and kill conditions, the basis on each side, and a protocol for the measurement.