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
    +7

    Comment number 45.

    @10 Im sure thats what they said when Ben Franklin was mucking around in thunderstorms instead of doing proper work too... I mean, what on earth could be the benefit to the economy of this newfangled electricity...

  • rate this
    +16

    Comment number 44.

    "ProfPhoenix
    Hopefully it can be employed to combat climate change. Otherwise the research would never have been funded."

    Well, it certainly is further vindication that the earth is more than 6000 years old. It may be news to you, but only a tiny proportion of the world's scientific funding goes to climate science.

  • rate this
    +6

    Comment number 43.

    To the person saying ten million million dollars spent. Billion is one thousand million - almost nobody uses the old system of a billion being a million million.

  • rate this
    +8

    Comment number 42.

    Congrats to all at Cern.

  • rate this
    +24

    Comment number 41.

    This is an amazing achievement for mankind. Anyone wondering whether constructing such an experiment is a waste of money, or how it will benefit society, are incredibly short-sighted. Congratulations to everyone at CERN.

  • rate this
    +47

    Comment number 40.

    For those here wondering what the benefit is and thinking that the money would be better spent on poverty etc ... the benefit will come in many years time when we learn how to harness and direct the forces of nature better.

    I think it has been demonstrated that throwing money at poverty does not cure it.

  • rate this
    -160

    Comment number 39.

    My Comment @ 8 see its marked down!
    While you are patting yourselves on the back, my question is simple, what practical benefits will this bring/
    Or is there no one smart enough out there to answer this?
    Do billions more need to be spent to find some use for this?

  • rate this
    +11

    Comment number 38.

    13.empiredown
    "A waste of money......This money should have been spent on climate change research not searching for elusive bits of nothingingness"

    I agree that climate change threatens the survival of the human race & much priority work is needed to negate the causes and effects. However Cern research did give us the WWW and who knows what benefits the Higgs boson will provide the human race

  • rate this
    +2

    Comment number 37.

    When I did Physics and Chemistry S levels we had protons, electrons, neutrons and quantum mechanics. Now we have all these other particles so my brain hurts. What happened to quantum mechanics?

  • rate this
    +13

    Comment number 36.

    Ahh science works on something people don't understand, and people like Pauline Fothergill (comment 18) only want to know how it will cure problems they can understand. There are more things in heaven and earth...

  • rate this
    +105

    Comment number 35.

    To all those people asking if the money could be better spent:
    Think of all the discoveries we take for granted which are the result of the curiosity of people (not necessarily just scientists).
    Refusing to explore science because of financial constraints would keep us all ignorant and remove any chance of spectacular new (useful) discoveries.

  • rate this
    +35

    Comment number 34.

    It always amazes me that there are people who do not see the value of experimental science. How on earth do those people think the Human race has got to where it's at without science? The pursuit of knowledge is one of the few noble things that I can point to in this modern world.

    Oh well, I suppose it's a case of each to their own.

  • Comment number 33.

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

  • rate this
    -95

    Comment number 32.

    Hopefully it can be employed to combat climate change. Otherwise the research would never have been funded.

  • rate this
    +8

    Comment number 31.

    This will now replace the moon landing as the preferred comparison when expressing frustration i.e, "They can find the higgs boson but they can't invent an oven chip that doesn't require turning at least once during cooking"

  • rate this
    +210

    Comment number 30.

    Naysayers already?

    Money spent on science is never wasted, it's an investment that increases our understanding of the universe, is usually repaid many times over by spin-offs and benefits that were never expected when the experiment was thought of, not to mention the training & experience of scientists involved.

    Put $10 Billion into bailing out the banks and it's gone before lunchtime.

  • Comment number 29.

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

  • rate this
    +10

    Comment number 28.

    And with the discovery of the Higgs boson, God promptly disappeared in a puff of logic.

    If only.

  • rate this
    -25

    Comment number 27.

    Awww, totally overwhelmed. It cost them a lot and life feels very different today.

  • rate this
    -4

    Comment number 26.

    I would like to know, if the Higgs Boson gives mass to the other elementary particles, why do the rest of the particles still exist, and how can they all still be seen and measured in particle accelerator experiments after the splitting of the particle?

 

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