CMS, one of the two Higgs-hunting experiments at the Large Hadron Collider, has reached a level of certainty worthy of a “discovery”.
The other experiment, Atlas, has yet to report its results.
The team claimed they had noticed a “bump” in their information corresponding to a particle weighing in at 125.3 gigaelectronvolts (GeV) – about 133 times heavier than the proton at the heart of each atom.
Indications are strong, but it remains to be observed no matter whether the particle the team reports is in fact the Higgs – these answers will undoubtedly not come on Wednesday.
The result announced at Cern, residence of the LHC in Geneva, was met with applause.
The CMS team claimed that by combining two of its information sets, the researchers had attained a self-confidence level just at the “five-sigma” point – about a one-in-3.5 million chance that the signal they see would seem if there had been no Higgs particle.
Even so, a complete mixture of the CMS data brings that quantity just back to 4.9 sigma – a one-in-2 million opportunity.
Massive difficulty Anticipation had been high and rumours had been rife before the announcement.
New information presented right here in Geneva have shown that researchers are now tantalisingly close to confirming the Higgs’ existence and bringing to an end the decades-extended quest for the most coveted prize in physics.
Along with 5 other theoreticians, Peter Higgs predicted the particle in the 1960s.
A confirmation would be one of the largest 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.
Two different experiment teams at the LHC observe a signal in the very same part of the “search region” for the Higgs – at a rough mass of 125 Gigaelectronvolts (GeV).
Hints of the particle, revealed to the planet by teams at the LHC in December 2011, have since strengthened markedly.
The $10bn LHC is the most powerful particle accelerator ever built: it smashes two beams of protons together at close to the speed of light with the aim of revealing new phenomena in the wreckage of the collisions.
The Atlas and CMS experiments, which were developed to hunt for the Higgs at the LHC, every single detect a signal with a statistical certainty of far more than 4.5 sigma.
5 sigma is the typically accepted benchmark for claiming the discovery of a new particle. It equates to a one in 3.5 million opportunity that there is no Higgs and the “bump” in the data is down to some statistical fluctuation.
Particle physics has an accepted definition for a discovery: a “5-sigma” (or five standard-deviation) level of certainty.
The quantity of sigmas measures how unlikely it is to get a certain experimental outcome as a matter of likelihood rather than due to a true impact.
Similarly, tossing a coin and obtaining a number of heads in a row may just be chance, rather than a sign of a “loaded” coin.
A “three-sigma” level represents about the identical likelihood as tossing eight heads in a row.
5 sigma, on the other hand, would correspond to tossing much more than 20 in a row.
Independent confirmation by other experiments turns five-sigma findings into accepted discoveries.
Physicists now contemplate it extremely unlikely that this signal will fade away.
Prof Stefan Soldner-Rembold, from the University of Manchester, told BBC News earlier this week: “The evidence is piling up… everything points in the direction that the Higgs is there.”
The Higgs is the cornerstone of the Standard Model – the most effective theory to explain the workings of the Universe.
But most researchers now regard the Common Model as a stepping stone to some other, much more total theory, which can explain phenomena such as dark matter and dark energy.
As soon as the new particle is confirmed, scientists will have to figure out regardless of whether the particle they see is the version of the Higgs predicted by the Common Model or some thing more exotic.
Scientists will look at how the Higgs decays or – transforms – into other, a lot more stable particles after becoming produced in collisions at the LHC.
“We’ll look at how typically it decays into a pair of photons, how often it decays into Z bosons, how often it decays into W bosons,” mentioned Dr Tara Shears, from the University of Liverpool.
“It could match what the Standard Model predicts, but if there are deviations, that means there is new physics at work. That would be the first glimpse through the window at what lies beyond our current understanding.”
Continue reading the main story The Standard Model and the Higgs boson
• 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 Modelholds together neatly, nothing requires the particles to have mass; for a fuller theory, the Higgs – or something else – must fill in that gap
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The LHC image from CERN Speculation is building in the international physics community about the contents of a press conference that has been called by scientists at the Large Hadron Collider (LHC), to be held at 9am Geneva time (3am EST) on July 4, 2012. Peter Higgs himself is flying to attend the press conference.