Is electroweak symmetry breaking a reversible process?

[feathermoon]

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.

 

[bapowell]

In principle, yes. Fundamental symmetries can be restored. Perhaps the easiest way to visualize is through analogy with ferromagnetism. Above a certain temperature (the Curie temperature), ferromagnetism is lost as the magnetic domains become randomly oriented. This is an example of symmetry restoration, since the system becomes fully rotationally symmetric. In the same way, at sufficiently high temperatures the vacuum of the Higgs field regains the full electroweak symmetry.

 

[AdrianTheRock]

I'd have thought this would be of relevance to high-energy particle collisions. Shouldn't there be an energy level above which we have to stop thinking of (eg) electrons and positrons annihilating into either photons or Z⁰s and instead start thinking/calculating in terms of W⁰ and B (or arbitrary combinations of the two)?

Can anyone here enlighten me on this?