I can only assume it is, if a Higgs can be found anyway. I learned about hysteresis in certain physical processes. I don't have the math to guess nor Google skills to find a clear answer. If it were, would a sufficiently large and hot enough black hole be in danger of losing its mass terms spontaneously (and so exploding or maybe recollapsing before matter could escape the event horizon because it cooled again and gained mass term)? At the other end, I'm interested in whether a photon could gain mass. Its probably obvious I'm not super good at physics so excuse me if this sounds stupid.