Mounting Evidence for the Existence of a Neutral Vector Boson

It is pointed out that the existence of a strangeness-zero, neutral, vector boson with mass $O\left(30\mathrm{} \mathrm{GeV}\right)$ and strong coupling to muons is consistent with the recent experimental results on the anomalous magnetic moment of the muon, the direct production of high-energy muons in cosmic rays, and the observations of multiple-core cosmic-ray events with high momentum transfers. A discussion is given in which two feasible experiments are mentioned that could test the model.