The Higgs Boson  Discovery!

By | July 4, 2012
… read the rest yourself. Happy lunch! and +João Serrano , no more flag waving now. 😉

Reshared post from +EuroTech

Congratulations Europe on Finding the Elusive God Particle!
by +Sophie Wrobel, +EuroTech; Germany

Today, almost fifty years after Peter Higgs theorized there should be another particle, European research center +CERN presented an update on the Higgs Boson particle. Here is what CERN Director General Rolf Heuer announced today:

“We have reached a milestone in our understanding of nature. The discovery of a particle consistent with the Higgs Boson pens the way to more detailed studies, requiring larger statistics, which will pin down the new particle’s properties, and is likely to shed light on other mysteries of our universe.”

Eureka, we have it!
The physicists at CERN have discovered a Higgs Boson. They are not sure which one, and will need additional tests to determine the nature of the this newly discovered boson, and which flavor it has – but they have made a milestone discovery.

Why is it called the God Particle?
The Higgs particle is responsible for explaining why we have mass, according to the latest theory of how the world works. Ever wonder why a proton is so heavy and and a photon so light? What makes a top quark heavier than any other subatomic particle – despite having no size? At these nanoscopic scales, density has nothing to do with mass. Instead, mass has to do with how much a particular particle interacts with the fields around it. 

Consider how electricity is made: turning a copper coil through a magnetic field induces a flow of electrons that we call current to produce electricity. Likewise, matter moving through a Higgs field induces a flow of Higgs Bosons to produce mass. Just as the electron is the particle of transmission for electricity, the Higgs Boson is the particle of transmission for mass. Finding the Higgs Boson experimentally confirms the theory of the Higgs field, proving that it is a correct explanation of why matter exists – a very creationist concept. For that reason, the Higgs Boson has been dubbed the God particle. 

How does one find the Higgs Boson?
Finding the Higgs Boson is no trivial task. Unlike electrons, the Higgs Boson has no size: pointing an incredibly strong microscope at an object in hopes of seeing it is futile. It is also extremely short-lived: it typically decays before reaching a detector. Thus the only chance we have is to look for the signature generated by its decay (experimentally found at 125.5 GeV). The trouble is, colliding two particles at immense speeds produces an array of other subatomic particles that have a longer lifespan, making it impossible to isolate the Higgs Boson. So we’re left with analysing the energy signatures from a large, mixed pond of subatomic soup decaying simultaneously. 

It’s a bit like looking for a particular spectral signature in the spectrum of light emitted from a distant star to show that the star burns Hydrogen and not Oxygen, when the star is constantly changing its fuel to create constant spectral signature changes. So we have to make a recording of the detected energy levels released by a high-speed subatomic particle collision, and then sift through that ‘video’ frame by frame searching using multiple statistical analysis techniques for the Higgs Boson decay signature – and once we find that, make sure it isn’t the result of ‘dust on the camera lens,’ or experimental uncertainties, or some other particle decay. Of course, the other particles decay in a predictable fashion, so we can rule out that signature being caused by another particle by analysing the recording using multivariate analysis and Monte Carlo analysis to independently correlate results in mass distribution observations.

CMS: “We have observed a new boson with a mass of 125.3 +/- 0.6 GeV at 4.9 sigma significance.”

CMS experimentation has observed state decay of a Higgs Boson to di-photon and four-lepton final state with a statistical significance of 5 sigma. The CMS team preliminary presented three channels on which they searched for evidence correlating to a Higgs Boson.The significance ranged from 3.2 sigma to 5.1 sigma. The most significant results, on the ZZ and gamma-gamma channels, have a combined significance of 5.2 sigma at 125 GeV. The more sensitive multivariate analysis is not yet available.

ATLAS: “We observe an excess of events at 126.5 GeV with local significance of 5.0 sigma.”

ATLAS experimentation on the same decays produced similar results to the CMS experiments. ATLAS discovered a 126.5 GeV mass resolution detected with 4.5 sigma significance on the decay to the di-photon final state, with a significance twice as large as expected. They found a stronger presence of the decay to the four-lepton final state by detecting four muons, four electrons, and 2e to 2mu events with a statistical significance of 5.0 sigma, again an extraordinary increase in detection sensitivity.

Why can’t scientists say they discovered it last year, instead of just ‘maybe?’
The trouble with announcing a discovery is that you have to be absolutely certain about what you are announcing. Last year’s ‘maybe’ announcement did not have a significantly strong signal to rule out the possibility that the signal was just noise. So this year, they have repeated the experiment with more power (8 TeV instead of 7 TeV from last year), which should give a 15% stronger signal on the di-photon channels, which is where the Higgs Boson signature is most prominently visible. The new data should see a 50% sensitivity increase on the di-photon channel. In order to announce a discovery, they need to obtain at least 5 sigma statistical confidence across all measurements. The combined data achieves this as their statistical confidence – last year’s announcement had a confidence of 3 sigma.

After analysing and reanalysing the recordings of particle collisions, the long-awaited results are in, and confirmed: the Higgs Boson decay has been sighted. Now we can all rest in peace knowing how matter has mass – and just as the discovery of the electron revolutionized the world, the discovery of the Higgs Boson is another milestone discovery that will revolutionize the world for the years to come, once we figure out just what we can do with this new particle.

That leaves us with the big question: who out of the thousands of researchers will get the inevitable Noble prize? One of the teams leaders? Fabiola Giannotti would be a great candidate as one of the few women in a male dominated world – or should it go Higgs himself who predicted the particle almost fifty years ago. His paper by the way was rejected: the editors of Physics Letters judged it “of no obvious relevance to physics” 🙂

Still puzzled? Don’t worry, even undergraduates have difficulty grasping the concept. Try the attached video to understand how crucial the Higgs particle and the Higgs field are for more modern physics.

Tags: #ScienceEveryday #Science

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