Gluon has spin when tail-chasing, and is neither up nor down. In fact, CERN, Livermore, Argonne, INL, Sandia, Max Planck, MEPhI, Oak Ridge, Hanford, Enrico Fermi, Les Horribles Cernettes, Fermilab, Brookhaven, Beijing Electron-Positron Collider, Institute for Advanced Studies, and other high-power, high-energy places haven't figured Gluon out yet. If it is possible to figure Gluon out. Not up, not down, no charm, no nothing, and yet good at retrieving antiparticles from black holes and humping legs. That's Gluon.