Thursday, 5 July 2012

Higgs Boson special

Physicists at the ATLAS and CMS experiments, at the LHC, have observed a spike at ~126 GeV (giga electron volts), which is compatible with the Higgs Boson.
This spike was observed after about 1,000,000,000,000,000 collisions, and has a three-millionth chance of being wrong!


Note that the release says "observed" - not "discovered" - which will require more, wider evidence.
To say that it is actually the Higgs Boson will require more analysis, but i might stick my amateurish neck out to say that it is "probably" the Higgs Boson ;-)

CERN's (the Organisation Européenne pour la Recherche Nucléaire) press release:

Click on the links for some groovy-looking graphs, and stuff. I've put a couple, further down...

"The results presented today are labelled preliminary. They are based on data collected in 2011 and 2012, with the 2012 data still under analysis. Publication of the analyses shown today is expected around the end of July. A more complete picture of today’s observations will emerge later this year after the LHC provides the experiments with more data.
The next step will be to determine the precise nature of the particle and its significance for our understanding of the universe. Are its properties as expected for the long-sought Higgs boson, the final missing ingredient in the Standard Model of particle physics? Or is it something more exotic?"

See link below for the answers to these questions:

1. What is the Higgs Boson?
2. Today CERN announced an update on the research, what did they find?
3. What more needs to happen for CERN scientists to confirm that the unexplained particle is indeed a Higgs Boson?
4. In the Standard Model, it is hypothesized that there is only one Higgs Boson, but in the Supersymmetric Model, there could be up to five Higgs Bosons. If they are able to verify the signal is indeed a Higgs Boson, how will they know if it is one of many?
5. If the Higgs verifies the Standard model, does more than one Higgs undermine it in favour of Supersymmetry?
6. If the Higgs Boson particle(s) is confirmed, what are the next stages of research?

Let's not leave the Tevatron team, in the USA, out, though; having accumulated data for a decade, which they published just before the CERN teams did.

"Our data strongly point toward the existence of the Higgs boson, but it will take results from the experiments at the Large Hadron Collider in Europe to establish a discovery."

Great video explanation of what the Higgs Boson is, and what it does:

"The Tevatron results indicate that the Higgs particle, if it exists, has a mass between 115 and 135 GeV/c2, or about 130 times the mass of the proton."
"Tevatron scientists found that the observed Higgs signal in the combined CDF and DZero data in the bottom-quark decay mode has a statistical significance of 2.9 sigma. This means there is only a 1-in-550 chance that the signal is due to a statistical fluctuation."

In contrast, the LHC's power means it has identified the particle to be between 125 and 126 GeV, with a sigma of 5, meaning a 1-in-3,000,000 chance that the signal is due to a statistical fluctuation. 5 sigma is considered to be the 'gold standard' for identifying new particles.

Some funky yet exciting graphs:


The strongest evidence for this new particle comes from analysis of events containing two photons. The smooth dotted line traces the measured background from known processes. The solid line traces a statistical fit to the signal plus background. The new particle appears as the excess, at around 126.5 GeV. The full analysis concludes that the probability of such a peak being non-determined is one in three million.
Dumbing this waaaay down, for ya -- that little bump, in the middle, is where the particle has been identified to be. The bigger the bump, in contrast to the crinkles of the line around it, the more sure we can be that it's really there, and not just a slightly bigger but still 'random' wiggle. There's a 0.000,000,3 chance that that bump is a fluke!

The Tevatron team's graph, showing the regions where we know the Higgs Boson isn't. The uncoloured band at ~125 matches up to CERN's data. Results replicated before the original! This is A-grade science, LOL :)


Forget the name 'God particle'. It was actually nicknamed the 'goddamn particle', but because journalists tend to be intellectually blunt, they vulgarly ran with 'God particle'!

'The Higgs boson was initially called the ‘goddamn particle’'

'Shy physicist whose name will live on in Higgs boson'

"Higgs says the first he knew of the particle having acquired his name was after a conference at Fermilab in Batavia, Illinois, in 1972. He heard from a colleague that the name "Higgs" had been attached to almost everything to do with theories of mass generation by the conference rapporteur, prominent physicist Ben Lee. "I have to accept that," Higgs says. "I think I was first to draw attention to the particle associated with it, and I go around pointing out that nothing else in this kind of theory was mine or mine alone." What Higgs does object to is the label "God particle". Though himself an atheist, he worries that the title "might offend people who are religious"."

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