25 Days of Particles: Day 20

Higgs Boson

Classification: boson
Fundamental: yes (we think)
Mass: Unknown, but most likely heavier than 114000 MeV
Interactions: weak
Spin: 0
Lifetime: Unknown

We're now going to change gears just a bit and take a few days to discuss particles that physicists wish would show up for the holidays. These are the theoretical particles, or particles that we have good reason to think actually exist, but that nobody's observed yet.

Let's take the Standard Model. When it was getting pulled together in the 1960s, trying to include mass was a bit of a problem. Mass terms could only be allowed if the masses were zero; otherwise, the Standard Model would predict that physical laws were different in different parts of the universe or other impossibilities. But the particle masses are not zero, not by a long shot. So to make the math behave, several physicists, Peter Higgs amongst them, developed a mechanism to include mass terms.

It required postulating that the universe was full of a field that interacted with all matter. Particles that interacted more strongly with the field were the more massive particles. But the field also produced a new particle, a scalar neutral boson which was called the Higgs boson.

The Higgs boson has been a big deal since it was theorized. It is the only remaining Standard Model particle to be discovered. Also, since the boson is related to how everything gets mass, it effects all particles, including all the ones we haven't discovered yet. Any theory that tries to explain how the universe was formed or anything like that has to establish how that would change. This is why the Higgs boson is hugely important and has garnered so many dramatic nicknames.

To be fair, some of those nicknames are not so flattering. See, physicists have been hunting for the Higgs boson for going on fifty years now, and haven't found it. The Large Electron-Positron collider looked for it, the Tevatron is looking for it, and the Large Hadron Collider is getting in on the search. We know there must be some evidence, in the form of particles or particle behavior, that explains how particles get mass. It might be the Higgs boson, or it might be something else. But there's got to be something, and we'd really like to find it and solve the puzzle. We've been hunting for a long time.