Heavy photons are too light to be behind dark matter

Heavy photons are too light to be behind dark matter: Some theories had hinted that "heavy photons", hypothetical versions of the more familiar massless particles, might be dark matter. According to that idea, the heavy photon would have a small amount of mass and might carry an unknown fundamental force that allows it to interact only with ordinary photons...
... a photon with a very tiny "in between" mass can enter into an orbit of the spinning black hole and steal some of its angular momentum...
Cardoso and colleagues calculated how long photons of given masses would take to sap a black hole's spin. Then they examined data on the ages and rotation speeds of eight supermassive black holes. The age of the oldest spinning black holes effectively puts an upper limit on the photon's mass. If it does exist, the heavy photon must be lighter than 10-20 electronvolts - an extreme improbability...