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
    +1

    Comment number 1665.

    #1653.Tchernobog
    "Observations used to verify the existence of Higgs boson are not directly falsifiable and therefore empirically invalid.

    Agreed.

    As we move further from the easy science of the lab bench into the complexities of cosmology and particle physics it becomes harder to apply strict scientific method.

    How should we improve our rigour in such areas?

  • rate this
    +1

    Comment number 1664.

    Okay, they've found the higgs boson, but where's Schrödinger's cat?

  • rate this
    -1

    Comment number 1663.

    "Derive your own opinion from your own deep-seated research - not your sofa science!", sayeth 1597 Gary.
    ~
    The LHC built from sofa science without one iota of scientific evidence but hey, technologists/engineers, impressive work, nevertheless. Pity it's for this & not for the general well-being of the rest of us cash-cows &, btw, I LOVE SCIENCE having had years & years of enjoyable study of it.

  • rate this
    -1

    Comment number 1662.

    1596 and 1610 you have missed my point completely.
    What I was (trying) to say is that although the discovery of the Higgs is a wonderful thing, it will NEVER solve the problem of hunger.
    Even if as 1610 so eloquently puts it "inertia-less vehicles" are a consequence of the discovery, unless there is profit to be made from feeding people, then it will not happen. Hence it can't feed people.

  • rate this
    0

    Comment number 1661.

    I have read the comments since I posted @1621 but I'm still left with the big question:

    WHAT IS IT?

    I mean, physically, actually, touchy freely. I have the same question about many theories. Science names, measures and adds more names.

    Are we getting closer or further away from understanding? In my 50 years since learning I'd say we are further away.

    That's not to debunk science in any way.

  • rate this
    +1

    Comment number 1660.

    I don't believe anyone designed the LHC. It simply appeared after a big bang in Cern, a bit like the universe.

  • rate this
    +2

    Comment number 1659.

    1612.Shift That Paradigm
    LHC was not built on proof it was built to provide the evidence that either proved or disprove theories
    In science the theory always comes first then they design build and do experiments with the sole intention of finding out if the theories are correct or not.
    theory, experiment, results, conclusions, then peer review to try to find any errors and only then publish

  • rate this
    0

    Comment number 1658.

    @1650. Shift That Paradigm

    You’re welcome!

    Given that my last post (1641) was a bit of a cop-out (400 characters), if you are really interested in how quantum physics does work, look up the following in a well-known online encyclopaedia:

    “Schrödinger's cat”, “observer effect”, “Heisenberg uncertainty principle”.

    Good luck!

  • rate this
    -1

    Comment number 1657.

    1643.Shift That Paradigm

    One thing I've understood from this blog is not to interrupt the 'scientists'.

    As nobody else has, I'll answer your question:

    The Quarks & the Gluons signed an intergalactic peace treaty some time last buzz light year, though how long it will last is largely down to the Americans, & the Swiss, now they've found something a bit like Higg's boatswain.

  • rate this
    +1

    Comment number 1656.

    @1641 Mike Davies and in response to @1612. Shift That Paradigm.

    Let's try to make this simple. LHC smashes thing like protons together. Protons are made of other stuff. If you drive two cars toward each other at 100mph and smash them into each other would you expect to discover a car door and only a car door? Of course not. You would expect to find the car door amongst a lot of other debris.

  • Comment number 1655.

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

  • rate this
    +1

    Comment number 1654.

    #1647 David Shepperd
    "i see genuine people saying exactly what you said and believing it too"

    Apologies. I must learn to discipline my irreverent sense of humour; or put "This is a joke" on each such post.

    Regarding God, believers should not to examine Him too closely. Apply logical analysis and he collapses.
    Try #28 for my take on Paley's Argument from Design, which is recursive.

  • rate this
    +1

    Comment number 1653.

    Pseudoscience.

    Observations used to verify the existence of Higgs boson are not directly falsifiable and therefore empirically invalid. What is absent from this discussion is the fact that NO particle observed in a collider can be used to test quark theory because quarks make no definitive predictions of particle masses.

    I.e. "confirming instances have no epistemic value whatsoever" (Lakatos)

  • rate this
    0

    Comment number 1652.

    1643.Shift That Paradigm
    no one answers my Qs on quarks, gluons, et c., ref 1612 & more. I wonder why. Not.

    Thats probably because it appears you're not really asking; just probing for your next rant! Good luck - see you next topic.

  • rate this
    0

    Comment number 1651.

    These guys spend a lot of time congratulating themselves. They spend money to build new forms of equipment that will tell them there is more than they thought. It is an unending persuit of what cannot be found.
    They don't seem to understand that the equipment that is being built is actually creating what they "uncover" and if there was no machine there would be nothing to "uncover"

  • rate this
    -2

    Comment number 1650.

    1641. Mike Davies @1612. [me] “Quark? Neutrino? Gluon? Messenger photon? Have they been detected singly & unambiguously?”
    No and they never will be. If the only evidence that you will accept is being able to pick one up with a microscopic pair of tweezers, you will remain unconvinced. Quantum physics doesn’t work that way.."
    ~
    Thank you for your input. I note your comments. Blessings.

  • rate this
    +3

    Comment number 1649.

    David Kelly and empiredown - people laughed at quantum theory, but without it we would have no computers, no mobile phones, and no SatNav.

    Expand your minds a little, please! This is a significant step forward, not just for science, but for international cooperation.

  • rate this
    +1

    Comment number 1648.

    1608.5ecret
    ...or the intra-lecture-all snobs who alienate 'ordinary' people from science?

    Hmmm.. not seen many of them here..

  • rate this
    +4

    Comment number 1647.

    1629.Entropic man
    Sorry then :)
    but i hope you understand i can only go on the words written as too many times i see genuine people saying exactly what you said and believing it too
    @1640
    science makes no judgement on god (lack of any useful data) does not comment on why we have the rules only tries to understand what those rules are
    science allows for a god religon does not allow for science

  • rate this
    +3

    Comment number 1646.

    The news has been leaked gradually to avoid Mass Hysteria.

 

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