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
    +6

    Comment number 105.

    "And the point is? i may be a luddite but ...I cannot see the point of spending Billions on this!!"

    I can't see the point of spending billions on warfare or football, but there y'go. Each to his own.

  • rate this
    0

    Comment number 104.

    Great news but I'm willing to bet that there will still be a 'hole' in the standard model once the new particle is fully characterized and added to the calculations. God particle II, the sequel, soon to be seen at your local LHC!

  • rate this
    +63

    Comment number 103.

    I love the way any scientific discovery is greeted by howls of protest at the huge waste of time and money it represents, with claims that the effort should have been spent on climate change or world hunger etc. The entire 14 year LHC project cost about the same as Tesco's annual profits and, if we hadn't spent the money on this, we would have frittered it on bank bailouts or aircraft carriers.

  • rate this
    +1

    Comment number 102.

    Research such as this is rarely a waste of money, it brings knowledge and often gives benefits that aren't expected. We need more things like this in many more fields of science.

    However, why are news articles about something REALLY useful rare? Something which noticeably improves lives like new clean fuel etc. surely the market is there, do big oil companies strangle this type of research?

  • rate this
    -5

    Comment number 101.

    Given this thing is 125 about GeV and a Proton is around 1 Gev, hence the 130 times mass. I assume that is not sub atomic, which to me seems strange.

  • rate this
    -11

    Comment number 100.

    I love science and the idea that there are still undiscoverd elements and particles, but can't help but think they're chasing unicorns in Geneva. It's an awful lot of money to spend on something that might not exist.

  • rate this
    -5

    Comment number 99.

    This could go on forever. What are these particles made of and how did they come into being? It wasn't so long ago the atom was the smallest thing, now it's a veritable bolder. I think we might reach the limits of our understanding before we reach the limits of reality.

  • rate this
    0

    Comment number 98.

    And at risk of some of my friends or colleagues guessing who 'sane or not' is, I'm a small part of it! Only on the computing side but its really amazing to have made a small contribution to something so special. There are so many amazing people in particle physics and the various technologies on which it depends I'm still in awe of many of them.

  • rate this
    +5

    Comment number 97.

    To the Luddites arguing about a waste of money...

    The theory of relativity might also not appear to have offered much to us mere mortals, but without such fundamental understanding we'd not have GPS, computing etc. It revolutionized our understanding of the nature of our existence.

  • rate this
    +1

    Comment number 96.

    Just shows that there will always be questions in front of us!!!

  • rate this
    -16

    Comment number 95.

    Without wishing to denigrate what is clearly some fantastic research work - easily up there with genome mapping - I do think that the trilliard-esque price tag carries with it an element of responsibility.

    Research for research's sake is fine when it comes to having an apple bounce off your head. But for that sort of money, the world will be looking for a practical application.

  • rate this
    +2

    Comment number 94.

    @71 The UK has used the short scale system since 1974; get with the times.

  • rate this
    +2

    Comment number 93.

    I can't believe that people in general can't see the obvious benefits these discoveries can bring. The point of this is to fully understand exactly how matter works, once we know that we can manipulate it with absolute precision & the entire universe then becomes our oyster. That is the point of it all in a nutshell folks!

  • rate this
    +11

    Comment number 92.

    The cost of the wars in Afghanistan/Iraq Roughly $3-4 Trillion!. The LHC $10 billion, its a miniscule amount so stop whining about cost.

    Just think though how much more we could achieve if all of that war money had been diverted into science, we could be on our way to fusion (hopefully ITER will work) solving climate change, and working on new propulsion systems for spacecraft.

  • rate this
    +222

    Comment number 91.

    Why spend money on pure science? It's infinitely more use to society than banking and stock trading and a fraction of the cost. Science defines the physical laws that govern our world, it's the job of engineers to put that knowledge to useful purposes. Ask Faraday about electromagnetism, Rutherford why he split the atom or Einstein about Lasers. None had any idea of their future benefits or use.

  • rate this
    +7

    Comment number 90.

    Well done! Fantastic achievement! To those braying about the cost - the search has been going on for 45 years. If you add up all the bankers' bonuses paid over this period, I think you'd see a comparable $ figure. I know who has contributed more to the future of mankind! Now we effectively know the standard model is correct, we push forward, and who knows what we'll find...? Very very exciting!

  • rate this
    +10

    Comment number 89.

    Anyone who doesn't believe in the fundamental value of science is a complete Boson, in my opinion...

  • rate this
    -10

    Comment number 88.

    44.Total Mass Retain
    "ProfPhoenix

    it certainly is further vindication that the earth is more than 6000 years old...only a tiny proportion of the world's scientific funding goes to climate science.
    @ I am pleased that this proves once again the world is over 6000 years old.Money well spent. I am sure that a portion of funding is not for climate change but it certainly attracts funds.

  • rate this
    -8

    Comment number 87.

    8.David Kelly
    And the point is? i may be a luddite but until someone can explain the practical applications

    =>It binds stuff into matter - useful to thicken custard and gravy.
    I also keeps a lot of scientists and their groupies off the benefits queue although, now they've found it, presumably there'll be redundancies.

  • rate this
    +6

    Comment number 86.

    Physics: Being too stupid to understand it is not proof of the existence of your god.

 

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