For decades, physicists have used a theory known as the Standard Model to explain the interactions of subatomic particles, and the theory works beautifully. It's guided our way through the world of nuclear power, television, microwave ovens and lasers. One problem: The theory needed something extra to explain why some particles have mass and some don't. Back in the 1960s, physicist Peter Higgs and his colleagues proposed the existence of a mysterious energy field that interacts with some particles more than others. That field is known as the Higgs field, associated with a particle called the Higgs boson.

With the announcement of new results today, people can easily get confused by 3-sigma, 5-sigma, "evidence" and "discovery", so Alan Boyle at Cosmic Log created this mini-guide to help clear up some terminology.  Our own Tommaso Dorigo also created a handy glossary as well.



Wait ... what's a sigma? Those numbers measure how likely it is that the effect seen amid the billions of collisions at the LHC is real rather than a statistical fluke. Suppose you have a machine that flips coins to check whether they've been stamped correctly with heads and tails, rather than two heads. You have to decide when to stop the conveyor belt to remove a coin with two heads, based purely on the machine's report. If the machine flips five heads in a row, you have more than 2 sigma confidence that there are heads on both sides of the coin. If it flips 10 heads in a row, the confidence goes up to more than 3 sigma. If it flips 20 heads in a row, you have a 5-sigma observation.

Read more: Higgs vs. hype: a mini-guide by Alan Blye Cosmic Log on MSNBC