Electroweak interaction

So the really interesting, weird thing transition was when we changed from having electricity and magnetism and the weak nuclear force being all aspects of the same thing to those separating out.

It's called the electroweak phase transition or the electroweak symmetry breaking.

So it used to be, back in the early times, back in the before times, there was no electricity, magnetism, and the weak nuclear force.

There was the electroweak force.

The electroweak force was something that acted like a combination of electricity, magnetism, and the weak nuclear force.

And there were different particles existing in the universe.

There were different forces, different particles.

Like, it's hard to even measure that with, like, clocks, right? But we know a picosecond after the start of the universe, whatever it was, we know what was happening.

So what happened after that?

So initially, as near as we can tell, all the forces, gravity, electroweak, electrostrong, electromagnetic, uh, were a force.

And we're, we're still trying to figure out how you get gravity in there.

We're trying to figure out how to get quantum gravity to be a thing.

But as near as we can tell, the first thing that happened was gravity split off and went, "Yo, I'm different."

Right.

A- and then electroweak and electrostrong together split off from the electromagnetic force.

And tho- and, like, there are four fundamental forces-

We'll come back to all of this in detail another time, but the one property that's relevant for today's episode is that these supersymmetric particles are all expected to be way more massive than their known partners in the standard model.

To solve the hierarchy problem perfectly, those particles would need to have masses at around what we call the electroweak energy.

That's the energy at which the electromagnetic and weak nuclear forces merge into the same force.

Physicists had hoped that by smashing particles together hard enough in the Large Hadron Collider, there'd be enough energy in those collisions to produce a supersymmetric particle and, in fact, there should have been, at least for the versions of SUSY that most neatly solve the hierarchy problem.

And in the 1990s, Frail, he was still working on high temperature superconductors.

The Electroweak was of course a summit, but he never stopped climbing.

Now, his personal life was a little unusual.

He married a second time, Lewis Johnson, a British citizen, who he had met in London in 1962 at all of the things, an anti-nuclear proliferation meeting.

Think of the universe mere fractions of a second after the Big Bang.

The cosmos was an intensely hot, incredibly dense state known as the electroweak vacuum.

The fundamental forces of nature were unified, but as the universe rapidly expanded, it rapidly cooled.

Yeah.

So his weapon was relentlessness and imagination, eventually building his own stage.

He presented the Electroweak theory, as it was called, at a big symposium in Sweden in 1968.

And for a while, it went unnoticed, clearly his amazing lecture skills.

And it took the CERN discovery to make the world look back and see what he, Glashow and Weinberg had done.

So, uh, this was, uh, very important work and it's kind of the most important work that's happened t-to finish out the Standard Model really, and was largely developed in the 1960s and into the 1970s.

Uh, this relates to the Higgs mechanism and the, the Higgs mechanism and associated electroweak force, the unification of the weak and electromagnetic forces.

So what's all this about? Let, let's introduce the players here.

I did say earlier that there was another type of boson, the Higgs boson, which is not a gauge boson.

It was a hypothesis which then led to this prediction which was subsequently verified when we discovered the Higgs boson so that's very nice.

But there's still a problem and those of you familiar with this may have noticed that there's something that I've skipped over and again I did that deliberately because you can't, you can't introduce everything at once.

Uh, it's, it's an important but in some ways minor detail, um, but it does need to be explained and this relates to the unification of the electromagnetic and the weak nuclear force together into the electroweak force.

When this theory of the Higgs mechanism was being developed in order to resolve this, you know, problem with the, the weak bosons having mass and, and reconciling that with the gauge invariance, the way I initially described it in terms of like you have your massless gauge bosons then they acquire mass by interacting with the Higgs mechanism whereas the photon doesn't interact with the Higgs field so it doesn't get a mass.