Higgs!

The entire universe in blog form
Oct. 8 2013 1:25 PM

Higgs!

Professor Peter Higgs
Professor Peter Higgs on July 6, 2012.

Photo by David Moir/Reuters

The Nobel Prize in Physics 2013 was awarded jointly to François Englert and Peter W. Higgs on Oct. 8 for their discovery of the Higgs Boson. Phil Plait wrote this post on July 4, 2012, when the discovery was announced.

Scientists using the Large Hadron Collider in Geneva have announced the discovery of a new subatomic particle to very high confidence that is consistent with what we expect the Higgs particle to look like.

Ye. GADS.

This plot shows the discovery as seen in one of the LHC detectors. Hang tight, and I'll explain it!

OK, the quick version. The Higgs particle is extremely important, because the Standard Model of particle physics - the basic idea of how all particles behave - predicts it exists and is what (indirectly) gives many other particles mass. In other words, the reason electrons, protons, and neutrons have mass is because of this Higgs beastie. Last year, the Guardian put up a nice article explaining this. A more technical discussion is on Discover Magazine's Cosmic Variance blog from 2007. Sean Carroll has been live-blogging the announcement, and has lots of good info as well.

This particle is very hard to detect, because it doesn't live long. Once it forms it decays in a burst of energy and other particles (think of them as shrapnel) extremely rapidly. The only way to make them is to smash other particles together at incredibly high energies, and look at the resulting collisions. If the Higgs exists, then it will decay and give off a characteristic bit of energy. The problem is, lots of things give off that much energy, so you have to see the Higgs signal on top of all that noise.

So, you have to collide particles over and over again, countless times, to build up that tiny signal from the Higgs decay. The more you do it, the bigger the signal gets, and the more confident you can be that the detection is real. I described all this in detail last December, when preliminary results from LHC were announced. I strongly urge you to read that first!

Back now? Good. So last year, an excess signal was seen at an energy around 125 GeV - that's a unit of energy physicists use, and it also indicates the mass of the particle decaying. Because energy and mass are interchangeable at some level, detecting the energy emitted when a particle decays tells you its mass.

A proton has a mass of about 1 GeV, so this excess found is about 125 times that much. Last year's results were tantalizing, but the strength of the signal only led to a confidence level of about 90% that it was real. Nice, but not enough to claim a discovery.

Today that all changed. Two different detectors at the LHC both independently found a strong signal between 125 and 126 GeV at about the 5 sigma level - that means they can claim a 99.9999% confidence this signal is real! This means they found a previously undiscovered particle which, as it happens, is within the range of mass the Standard Model predicts for the Higgs particle! That's what that plot above shows: a bump in the energies detected, and it's seen so strongly that it can be called a discovery.

That's huge.

Now technically, that's all the physicists can say: the particle is definitely there. But is it the Higgs? Well, to be fair, they can't actually say that. But if it walks like a Higgs, looks like a Higgs, and quacks like a Higgs... yeah.

So there you have it. A new fundamental particle has been found, and if it's the Higgs - which it really really really looks like it is - is the first step to our truly understanding such basic concepts as mass and gravity in the Universe. It's technical, and it's complicated, and it's the result of a vast amount of time, money, and effort by thousands upon thousands of people... but it's real.

And it's only the first step. There's much work to be done. But oh, what a step. The Universe has once again done something wonderful -- let us peek behind the curtain and get a glimpse of its inner workings.

Never forget this either: we humans did this. The discovery of this new particle, and the vast potential it has, was all because we're curious. This huge machine, the LHC, was built solely because we wanted to find things out, and some people had the vision to fund it and build it. When we wish to explore, when we wish to see what's over the next hill, wonders unfold before us.

All we have to do is want it enough.

Image credit: CERN

 


Related Posts:

- Mass effect: Maybe Higgs, maybe not
- Europe: Day 3 — CERN! The LHC!
- Brian Cox calls ‘em like he sees ‘em
- LHC smacks some phrotons (with video I took when I visited the LHC in 2008)

 

Phil Plait writes Slate’s Bad Astronomy blog and is an astronomer, public speaker, science evangelizer, and author of Death From the Skies!  

TODAY IN SLATE

Politics

Meet the New Bosses

How the Republicans would run the Senate.

The Government Is Giving Millions of Dollars in Electric-Car Subsidies to the Wrong Drivers

Scotland Is Just the Beginning. Expect More Political Earthquakes in Europe.

Cheez-Its. Ritz. Triscuits.

Why all cracker names sound alike.

Friends Was the Last Purely Pleasurable Sitcom

The Eye

This Whimsical Driverless Car Imagines Transportation in 2059

Medical Examiner

Did America Get Fat by Drinking Diet Soda?  

A high-profile study points the finger at artificial sweeteners.

The Afghan Town With a Legitimately Good Tourism Pitch

A Futurama Writer on How the Vietnam War Shaped the Series

  News & Politics
Photography
Sept. 21 2014 11:34 PM People’s Climate March in Photos Hundreds of thousands of marchers took to the streets of NYC in the largest climate rally in history.
  Business
Business Insider
Sept. 20 2014 6:30 AM The Man Making Bill Gates Richer
  Life
Quora
Sept. 20 2014 7:27 AM How Do Plants Grow Aboard the International Space Station?
  Double X
The XX Factor
Sept. 19 2014 4:58 PM Steubenville Gets the Lifetime Treatment (And a Cheerleader Erupts Into Flames)
  Slate Plus
Tv Club
Sept. 21 2014 1:15 PM The Slate Doctor Who Podcast: Episode 5  A spoiler-filled discussion of "Time Heist."
  Arts
Television
Sept. 21 2014 9:00 PM Attractive People Being Funny While Doing Amusing and Sometimes Romantic Things Don’t dismiss it. Friends was a truly great show.
  Technology
Future Tense
Sept. 21 2014 11:38 PM “Welcome to the War of Tomorrow” How Futurama’s writers depicted asymmetrical warfare.
  Health & Science
The Good Word
Sept. 21 2014 11:44 PM Does This Name Make Me Sound High-Fat? Why it just seems so right to call a cracker “Cheez-It.”
  Sports
Sports Nut
Sept. 18 2014 11:42 AM Grandmaster Clash One of the most amazing feats in chess history just happened, and no one noticed.