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2 August 2012
Graphic above: Protons collide in the CMS detector at 8 TeV, forming Z bosons which decay into electrons (green lines) and muons (red). Such an event is compatible with the decay of a Standard Model Higgs boson (Image: CMS).
The ATLAS and CMS collaborations today submitted papers to the journal Physics Letters B outlining the latest on their searches for the Higgs boson. The teams report even stronger evidence for the presence of a new Higgs-like particle than announced on 4 July.
Graphic above: Protons collide in the ATLAS detector, producing two pairs of electrons (red and blue). Such an event is compatible with the decay of a Higgs boson (Image: ATLAS).
On 4 July the experiments reported indications for the presence of a new particle, which could be the Higgs boson, in the mass region around 126 gigaelectronvolts (GeV). Both ATLAS and CMS gave the level of significance of the result as 5 sigma. On the scale that particle physicists use to describe the certainty of a discovery, one sigma means the results could be random fluctuations in the data, 3 sigma counts as evidence and a 5-sigma result is a discovery.
Video: What is the Higgs boson?
The CMS results reported today reach a significance of 5.0 sigma, and the ATLAS team's results reach 5.9 sigma. The value corresponds to a one-in-550 million chance that in the absence of a Higgs such a signal would be recorded.
Note:
CERN, the European Organization for Nuclear Research, is one of the world’s largest and most respected centres for scientific research. Its business is fundamental physics, finding out what the Universe is made of and how it works. At CERN, the world’s largest and most complex scientific instruments are used to study the basic constituents of matter — the fundamental particles. By studying what happens when these particles collide, physicists learn about the laws of Nature.
The instruments used at CERN are particle accelerators and detectors. Accelerators boost beams of particles to high energies before they are made to collide with each other or with stationary targets. Detectors observe and record the results of these collisions.
Founded in 1954, the CERN Laboratory sits astride the Franco–Swiss border near Geneva. It was one of Europe’s first joint ventures and now has 20 Member States.
Find out more:
ATLAS paper: http://arxiv.org/abs/1207.7214
CMS paper: http://arxiv.org/abs/1207.7235
About the Higgs boson: http://press.web.cern.ch/press/background/B01-Higgs_en.html
Symmetrybreaking: Physicists show strengthened signals of Higgs-like particle: http://www.symmetrymagazine.org/breaking/2012/08/01/physicists-show-strengthened-signals-of-higgs-like-particle-in-publications/
Graphics, Video, Text, Credit: CERN.
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