Tuesday, May 3, 2011

Potentially exciting news in the world of particle physics!

This happened about a month ago, and I've been doing some reading in my spare time about it, but I think now's the time to make a post about it.

It's big news for particle physicists, but I doubt you've heard this on the evening news. The Tevatron particle accelerator at Fermilab in Illinois has data that potentially points to the existence of a NEW fundamental particle.

Currently, physicists describe all the fundamental interactions in nature (except for gravity) by something called the Standard Model. It's done well for the time it's been around, but most physicists believe it's incomplete. Fermilab may have found proof of this.

A particle accelerator is a large device that sends two beams of charged particles in opposite directions. When these beams collide, the particles in the beam break apart and energy is released. This energy sometimes reforms into different types of particles, and the rules governing this are contained in the Standard Model.

Take a look at the graph above. The red line is what they would expect to see with the collisions they were doing. The black dots are the data collected. The blue line is a curve fitted to the bump in the dots - this is what they are excited about. Because that bump isn't predicted, it could mean a new particle previously unknown to physicists!

Of course, there's another possibility - this is statistical deviation from what we expect. The probability of this being the case is about 1 in 45. I like those odds, but they are far from conclusive. Only time will tell! This problem looks like it will be solved in the coming months by data collected at the LHC in Switzerland and France.



  1. I hear that carefully dealing with background noise can be a bitch...

    Exciting news, at any rate. In science, the unexpected is always welcome.

  2. Cool, I have a quick question though. If they did find a new fundamental particle how do they know it exists in nature? What I mean is how do they know it is not only lab created?

    Great post by the way, I have not been here in a while but your posts are now very accessible as compared to the beginning of the semester.

  3. Well Carlos, if it exists in a particle accelerator, then it certainly exists in nature.

    Let me explain. We use accelerators because they are a controlled environment that we can make high energy collisions. The controlled part is important. There's way too much background stuff to measure outside of a controlled environment. The truth is, there are events like what are happening in particle accelerators happening all the time, but gathering data from them is very very challenging.

    One example - cosmic rays. High energy particles from space are striking the atmosphere at WAY higher energy than we will produce in current (or maybe even future) particle accelerators. Thus, if they exist in particle accelerators, then they are most certainly occurring in nature.

    I really wish I had time to do a few posts on elementary particle physics, but alas, I did not. I highly recommend further reading on the wikipedia page for the standard model, as this tells a lot about the way things work at a fundamental level.

    Standard Model

  4. Too bad it'll take so long to know this for sure.