Measured distribution of cloud chamber tracks from radioactive decay: A new empirical approach to investigating the quantum measurement problem

Abstract Using publicly available video of a diffusion cloud chamber with a very small radioactive source, I measure the spatial distribution of where tracks start and consider possible implications. This is directly relevant to the quantum measurement problem and its possible resolution, and it appears never to have been done before. The raw data are relatively uncontrolled, leading to caveats that should guide future, more tailored experiments. Aspects of the results may suggest a modification to Born’s rule at very small wave function, with possibly profound implications for the detection of extremely rare events such as proton decay, but other explanations are not ruled out. Speculatively, I introduce two candidate small-wavefunction Born rule modifications: a hard cutoff and an offset model with a stronger underlying physical rationale. Track distributions from decays in cloud chambers represent a previously unappreciated way to probe the foundations of quantum mechanics and a novel case of wave functions with macroscopic signatures.