"The MiniBooNE experiment has detected far more neutrinos of a particular type than expected, a finding that is most easily explained by the existence of a new elementary particle: a “sterile” neutrino that’s even stranger and more reclusive than the three known neutrino types. The result appears to confirm the anomalous results of a decades-old experiment that MiniBooNE was built specifically to double-check."
However, there could be even more particles in the Zoo.
see: Rigid String Construction Theory, based on 4x Macaroni shaped parts, connected by 3x 90 Degree Freedom Hinges: 4x freedom rotations (O,U,L,R). Out of one Axion/Higgs (OOO) Vacuum Field particle comes: 2x Fermions, (e-,e+), 6x monopole Photon/Gluons, and 9x different shaped Neutrinos and one Majorana. (According to Quantum FFF Theory) below.