Higgs boson-like particle discovery claimed at LHC

 

The moment when Cern director Rolf Heuer confirmed the Higgs results

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Cern scientists reporting from the Large Hadron Collider (LHC) have claimed the discovery of a new particle consistent with the Higgs boson.

The particle has been the subject of a 45-year hunt to explain how matter attains its mass.

Both of the Higgs boson-hunting experiments at the LHC (Atlas and CMS) see a level of certainty in their data worthy of a "discovery".

More work will be needed to be certain that what they see is a Higgs, however.

Prof Stephen Hawking tells the BBC's Pallab Ghosh the discovery has cost him $100

The results announced at Cern (European Organization for Nuclear Research), home of the LHC in Geneva, were met with loud applause and cheering.

Prof Peter Higgs, after whom the particle is named, wiped a tear from his eye as the teams finished their presentations in the Cern auditorium.

"I would like to add my congratulations to everyone involved in this achievement," he added later.

"It's really an incredible thing that it's happened in my lifetime."

Prof Stephen Hawking joined in with an opinion on a topic often discussed in hushed tones.

"This is an important result and should earn Peter Higgs the Nobel Prize," he told BBC News.

"But it is a pity in a way because the great advances in physics have come from experiments that gave results we didn't expect."

'Dramatic'

The CMS experiment team claimed they had seen a "bump" in their data corresponding to a particle weighing in at 125.3 gigaelectronvolts (GeV) - about 133 times heavier than the protons that lie at the heart of every atom.

The BBC's George Alagiah explains the Higgs boson

They claimed that by combining two data sets, they had attained a confidence level just at the "five-sigma" point - about a one-in-3.5 million chance that the signal they see would appear if there were no Higgs particle.

However, a full combination of the CMS data brings that number just back to 4.9 sigma - a one-in-two million chance.

Prof Joe Incandela, spokesman for CMS, was unequivocal: "The results are preliminary but the five-sigma signal at around 125 GeV we're seeing is dramatic. This is indeed a new particle," he told the Geneva meeting.

The Atlas experiment results were even more promising, at a slightly higher mass: "We observe in our data clear signs of a new particle, at the level of five sigma, in the mass region around 126 GeV," said Dr Fabiola Gianotti, spokeswoman for the Atlas experiment at the LHC.

Peter Higgs Peter Higgs joined three of the six theoreticians who first predicted the Higgs at the conference

Prof Rolf Heuer, director-general of Cern, commented: "As a layman I would now say I think we have it."

"We have a discovery - we have observed a new particle consistent with a Higgs boson. But which one? That remains open.

"It is a historic milestone but it is only the beginning."

Commenting on the emotions of the scientists involved in the discovery, Prof Incandela said: "It didn't really hit me emotionally until today because we have to be so focussed… but I'm super-proud."

Dr Gianotti echoed Prof Incandela's thoughts, adding: "The last few days have been extremely intense, full of work, lots of emotions."

A confirmation that this is the Higgs boson would be one of the biggest scientific discoveries of the century; the hunt for the Higgs has been compared by some physicists to the Apollo programme that reached the Moon in the 1960s.

Statistics of a 'discovery'

Swiss franc coin
  • Particle physics has an accepted definition for a "discovery": a five-sigma level of certainty
  • The number of standard deviations, or sigmas, is a measure of how unlikely it is that an experimental result is simply down to chance, in the absence of a real effect
  • Similarly, tossing a coin and getting a number of heads in a row may just be chance, rather than a sign of a "loaded" coin
  • The "three sigma" level represents about the same likelihood of tossing nine heads in a row
  • Five sigma, on the other hand, would correspond to tossing more than 21 in a row
  • Unlikely results are more probable when several experiments are carried out at once - equivalent to several people flipping coins at the same time
  • With independent confirmation by other experiments, five-sigma findings become accepted discoveries

Scientists would then have to assess whether the particle they see behaves like the version of the Higgs particle predicted by the Standard Model, the current best theory to explain how the Universe works. However, it might also be something more exotic.

All the matter we can see appears to comprise just 4% of the Universe, the rest being made up by mysterious dark matter and dark energy.

A more exotic version of the Higgs could be a bridge to understanding the 96% of the Universe that remains obscure.

Scientists will have to look at how the Higgs decays - or transforms - into other, more stable particles after being produced in collisions at the LHC.

Dr Pippa Wells, a member of the Atlas experiment, said that several of the decay paths already showed deviations from what one would expect of the Standard Model Higgs.

For example, a decay path where the Higgs transforms into two photon particles was "a bit on the high side", she explained.

These could get back into line as more statistics are added, but on the other hand, they may not.

"We're reaching into the fabric of the Universe at a level we've never done before," said Prof Incandela.

"We're on the frontier now, on the edge of a new exploration. This could be the only part of the story that's left, or we could open a whole new realm of discovery."

The Standard Model and the Higgs boson

Standard model

The Standard Model is the simplest set of ingredients - elementary particles - needed to make up the world we see in the heavens and in the laboratory

Quarks combine together to make, for example, the proton and neutron - which make up the nuclei of atoms today - though more exotic combinations were around in the Universe's early days

Leptons come in charged and uncharged versions; electrons - the most familiar charged lepton - together with quarks make up all the matter we can see; the uncharged leptons are neutrinos, which rarely interact with matter

The "force carriers" are particles whose movements are observed as familiar forces such as those behind electricity and light (electromagnetism) and radioactive decay (the weak nuclear force)

The Higgs boson came about because although the Standard Model holds together neatly, nothing requires the particles to have mass; for a fuller theory, the Higgs - or something else - must fill in that gap

Paul.Rincon-INTERNET@bbc.co.uk and follow me on Twitter

 

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  • rate this
    +2

    Comment number 1445.

    1437. jurassic_clark

    Then you will have the opportunity to comment on the peer review of the papers publishing these results either before publication if invited to be a peer reviewer or via letters to the journals after publication. I'm sure you will avail yourself of these opportunities. Maybe you have found the fatal flaw in 50 years of experiments in standard model physics. Yeah, right.

  • rate this
    +1

    Comment number 1444.

    Let's pray any subsequent understanding in this field is put to use in benefitting the planet and not used to create more WMDs.

    A gripe: "... Higgs, after whom the particle is named ..."

    Actually, its named after Higgs and the Indian physicist Satyendra Nath Bose whose pioneering work in the early 1920s identified the particles which bear his name, But didn't bag him a Nobel Prize ... Odd.

  • rate this
    0

    Comment number 1443.

    1423. Space1999: Capiche. But have we really established that there are no circumstances under which the Higgs doesn't immediately decay? Can they be cooled to a BEC without decaying, and thereby prevented from decay? It seems there's little evidence for super-symmetry as yet.

  • rate this
    0

    Comment number 1442.

    1428.Bellatori

    Aaargghh! 400 chars is not enough and 10 mins to reply is difficult.

    I love both maths and physics. I was just trying to suggest to an earlier poster the difference between the two.

    I could not be happier knowing that 100+ countries are prepared to stump up hard cash in order to get a better understanding of the world.

    Gives me hope for the future.

  • rate this
    0

    Comment number 1441.

    Fantastic day! The world has found a new particle after a very long time! Higgs or not, this will advance our understanding of the universe in a major way and will lead to new capabilities for our species that we as yet don't understand. We would be naive to think we have an understanding of the universe having only lasted for a few secs in the life of the universe, but it's a big step forwards

  • rate this
    0

    Comment number 1440.

    1422 Bellatori

    Just because most of the Millenium Prize problems haven't yet been proven (or disproved) doesn't mean they can't be in principle. There are theorems in mathematics that cannot be proven though, as an example it has been proven both that a) you cannot prove and b) you cannot disprove the continuum hypothesis using the standard axioms of set theory.

  • rate this
    -1

    Comment number 1439.

    Of those people who truly impress me there are those who
    * create music I could not imagine
    * create literature I could not compose
    * think things I could not dream

    It makes me sad that there are those who would belittle the titans who stride amongst us. Why be jealous? Professor Higgs, I salute you.

  • rate this
    -4

    Comment number 1438.

    Just been down the High Street. I saw a God-like person.
    Come to think of it, there were hundreds of them.

  • rate this
    -3

    Comment number 1437.

    This is all a bit disingenuous. They have an observation at 125GeV. They do not know it is a Higgs Boson, they are claiming it without proof. I have worked in mass spectrometry for 20 years. I know chance events can combine to give a signal at exactly the right m/z. The harder you look, the more likely you are to see an artifact. Be honest. 2 dodgy data sets = 5 sigma? Get a job in a bank!

  • rate this
    -2

    Comment number 1436.

    I'll be surprised if today is July 4, 2012 announced the discovery of the Higgs boson. This will be the biggest fraud in the history of science.

    Higgs boson is contrary to Einstein's theory when the mass is formed as a result of the curvature of space-time.

    Dr. Vladimir Leonov
    http://www.blogger.com/profile/03427189015718990157

  • rate this
    -3

    Comment number 1435.

    So let me get this straight.. these really smart folks with a fancy machine discover the spark of creation on the same year Mayans predict the end of creation?? I'm no genius, just add it up.. and stay dry apparently =)

  • rate this
    -1

    Comment number 1434.

    Well done to the team at LHC.
    Their achievemnts cannot be overstated.

    Is it true, however, that George Osbourne has already formulated a new "Higgs Tax"?

  • Comment number 1433.

    This comment was removed because the moderators found it broke the house rules. Explain.

  • rate this
    -1

    Comment number 1432.

    1422.Bellatori & 1429.Doctor Bob

    It's good to see people can take a joke, OK I'll stop now and get serious. So if we have finally discover the Higgs Boson, what's to say that we can manipulate it? Perhaps it's only something observable but not manipulateable (I'm sure that's not a real word but nevermind).

  • rate this
    0

    Comment number 1431.

    1422.Bellatori

    Yup, thanks for pointing that out. I did try and correct myself!!

  • rate this
    +2

    Comment number 1430.

    #1413: "Noticed now that is has been discovered, the atheist, anti God media have stopped calling it 'The God particle '"

    That's only ever been a populist name, first used in Leon Lederman's book of the same title. Lederman has claimed that he would prefer to call it "the Goddamn particle" but couldn't get it past the publishers. Its just a name - nothing to do with the existence of deities!

  • rate this
    0

    Comment number 1429.

    1415.Golgotha
    I've just formulated the"Golgotha particle"theory to try to explain a shift in mass which allows complete transformation of an individuals physique when consuming C2H5OH. Can we use CERN to test it?

    =>LOL. You'll find a much cheaper supply of C2H5OH at your local hostelry which will finance a lot more experiments. Do check that your transmogrifications aren't on the turn!

  • rate this
    0

    Comment number 1428.

    1425. Paul A physicist needs a £2.6bn budget
    So we could have 3+ Higgs for one Olympics or 1 Higgs for 1 sellafield MOX plant or...

    OK so I know which I am voting for.

    On the other hand we make them all do maths... that would be cheaper. Problem is, it is only when you make them build the mathematical model that you find the flaws.
    Aristotle believed logic was everything. Remember Phlogiston?

  • rate this
    +2

    Comment number 1427.

    Zen Proverb:

    If you understand, things are just as they are;
    If you do not understand, things are just as they are.

  • rate this
    -1

    Comment number 1426.

    STAR GATE

 

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