PFE029: The Higgs Mechanism Part 2 - How It Acts

Last week, we heard about why we need the Higgs mechanism to fit in with everything else we know about little things. This week we are going to look at "how it interacts with stuff".

Personally I've always been a fan of this

graphic but whatever, it's super confusing. Let's start with the Higgs at the bottom. The line connecting it to itself means that it interacts with itself. The rest of the lines coming out of it means that it interacts with quarks, W and Z bosons [the weak bosons] and some of the leptons [in particular, the electron plus two others]. Notably absent from that list are gluons, photons, and those other leptons [neutrinos].

Okay, what?

It turns out that these are the particles that have mass. Of course, this is what was mentioned last week. Particles that have mass - a resistance to motion - interact with the Higgs. So the Higgs must somehow resist motion. Since the mass of a particle is proportional to how strongly it interacts with the Higgs, it appears that the Higgs itself, somehow, causes a resistance to motion.

Remember that pushing a monster truck is hard even in space with no gravity and no friction - that's because it still has a giant mass.

At this point people usually try to describe the Higgs as something like "sand that we are all moving through that slows us down - the heavier we are, the more we slow down". Of course this is a terrible description. Okay, not terrible, but still misleading.

The problem is that now everyone is thinking about aerodynamics - a frisbee flying in the regular fashion or flopping through this "Higgs sand" all sideways. But of course, that has nothing to do with it. The frisbee interacts with the Higgs field in the same way no matter how its moving.

Let's think of it a different way - in terms of what doesn't interact with the Higgs. Well there are gluons, but no one wants to have to think about those if they don't have to. There are neutrinos, but since the question of their mass is rather complicated and unclear, we'll ignore them too. Luckily, we still have photons or light - something that we are all familiar with!

Light particles don't interact with the Higgs - they may cross paths, but won't even notice it. What evidence of that do we see? They go at the speed of light!

"Wow, thanks there. Light goes at the speed of light? Great one. Now it all makes perfect sense."

Don't think of "the speed of light" as, well, "the speed of light" quite so much - think of it as the universal speed limit. The fastest that anything is allowed to go.

And since photons don't interact with the Higgs, they are always cruising along at a chill 669 million miles per hour.

But everything else [people and cars and toasters are made up of quarks and electrons] travels slower because they keep interacting with the Higgs field so much.

At this point its somewhat important to differentiate between the Higgs field and the Higgs boson. The field exists everywhere. It is here. It is there. It is in a box. It is in a fox. At any time and at any place, any particle that is allowed to interact with it [quarks, airplanes, electrons,... but not photons] does. This constant uniform behavior makes sure that all electrons have the same mass everywhere.

The boson - the particle - associated with all this nonsense, is a result of the fact that the field interacts with itself. A field doesn't have to do this, but because this one does, the Higgs boson itself has a mass.

That's how the Higgs acts.