Fourth flavor of neutrino? Physics experiment suggests existence of new elementary particle
Neutrinos are neutral elementary particles born in the radioactive decay of other particles. The known "flavors" of neutrinos are the neutral counterparts of electrons and their heavier cousins, muons and taus. Regardless of a neutrino's original flavor, the particles constantly flip from one type to another in a phenomenon called "neutrino flavor oscillation."
An electron neutrino might become a muon neutrino, and then later an electron neutrino again. Scientists previously believed three flavors of neutrino exist. In this Mini Booster Neutrino Experiment, dubbed MiniBooNE, researchers detected more oscillations than would be possible if there were only three flavors.
"These results imply that there are either new particles or forces we had not previously imagined," said Byron Roe, professor emeritus in the University of Michigan's Department of Physics, and an author of a paper on the results newly published online in Physical Review Letters.