What the heck is a boson?

Particles are strange. In more than one way: for example they behave as if they were spinning, like a top. But they aren’t moving at all. Even if they were, trying to imagine how some of them “spin” would probably melt your brain. The property that measures this “spinning” (though nothing is moving at all here!) is, creatively, called spin.

Continue reading

How do physicists find particles?

If you heard the news this summer that CERN actually didn’t find the particle they thought they saw, you may have realized the whole process is quite obscure. Some time ago, Abstrusegoose (rest its soul) put together this hilarious strip, that is kind of illuminating on how high energy physics works.

It’s a tad fuzzy on the details, but the basic process is the same*, just with protons (or other particles) instead of frogs. In short: you smash them real hard into each other and see what comes out.

Protons and frogs have several key differences, two of which are crucial for us. First: a proton is not a solid object, there is nothing really inside it. Second, if we put back the pieces of the two frogs we would get back two frogs. Nothing less (if we’re really good at not missing pieces), but most definitely nothing more. For particles that is very much not the case.

Accelerators like the LHC push particles very close to the speed of light. Because mass can turn into energy and vice-versa, the formidable energy released when the particles collide can produce all sorts of exotic particles that were not there before. And they can be more massive than the stuff we started with: the faster the particles, the more massive stuff can be “created”. The famous Higgs boson, for example, was discovered colliding protons, but it’s about 60 times more massive. It’s as if the collision of two frogs produced something the size of a 3rd grader.

However, it’s impossible to directly see these new particles, partly because of their very short lives. Much less than a billionth of a second after the collision that created them, they decay, shooting photons and small particles every which way.

You know those pretty pictures with all the colored lines that particle labs put out? Thelines are the trajectories of this debris shooting out of the collision.

alice-proton-lead

Credit: home.cern

And that’s the stuff physicists actually look at. There are detectors all around the collision point to measure and track and count how much of what sort subatomic junk came out and where it went. Knowing what each particle is expected to decay into, scientists can then sort through the debris and figure what happened.

If too much or too little of something comes out, it can mean that a new, unknown particle formed in the collision, which is why everyone got excited over CERN data late last year. Or it could mean that the models that tell us what to expect are wrong, which is still interesting. Or it could mean that usual particles just happened to decay more often in a particular way. This was the case with the CERN data: looking at more collisions, the averages eventually reverted to normal. No new particle for us.

 

Cover photo: LHC, CC-BY-NC-ND UCI UC Irvine via Flickr. Some rights reserved.

*Pedantic watch: I know the frog accelerator is not a collider, and LHC doesn’t quite work that way. On the other hand, that’s close enough: he’s also using frogs!

How to discover an element

Want to name an element on the periodic table? Piece of cake! Just follow this simple, step-by-step guide.

The first thing you have to do is to discover an element. At the moment, the periodic table has no blank spots to be filled: all elements with 118 or fewer protons have been found already. Though luck. Moreover, since very crowded nuclei don’t stick together for long, there aren’t any of these very heavy elements in nature. So you’ll have to manufacture them.

This might require some work.

Simplifying (a lot), to create a new element you have to smash together two existing ones and hope they stick. For example, to find the the lastest four earlier this year, scientists put Calcium atoms in an accelerator and threw them at target Berkelium atoms.

All elements in the universe formed in some version of that method, fusing together lighter ones. Inside the core of stars, for example, this reaction can produce energy, keeping atoms fizzing around and fueling the star. Very heavy elements (meaning heavier than Iron), however, consume energy to fuse together, so they need an energy source to do it. The staggring energy released during a star explosion is more than enough, and that’s where most heavy elements come from.

Nucleosynthesis_periodic_table

Chi ha fabbricato gli elementi. CC-BY-SA: Cmglee, via Wikipedia

You don’t need the nucleus to stay together long: a hundred-thousandth of a billionth of a second will do. But you need enough time data to figure out how many protons it has. Counting neutrons isn’t required. Nobody cares about neutrons.

Ok, step 2: publish your discovery on a scientific journal and wait for someone to replicate your experiment.

Only once your atom has been reproduced by someone else, you can move to step 3: get in touch with the International Union for Pure and Applied Chemistry (IUPAC). They will analyze your results and eventually officially announce your discovery, giving the element a temporary name.

Congratulations! As the discoverer, you get to take the final step: pick a name. Which you’ll have to agree on with the thousand of people you must have worked with to make it this far. You can choose whatever name you want. As long as it is after a mythological reference, a scientist, place, mineral or property, and that IUPAC approved it.

All in all, naming an element isn’t too different from naming a baby: for example there’s a bunch of rules, and your collaborators have to agree on the name too. But at least the first step for babies is a little easier…

 

Cover photo: Pizza lab, CC-BY-NC-ND clement127, via Flickr. Some rights reserved.