Posts Tagged ‘Large Hadron Collider’

ATLAS and CMS publish observations of a new particle in the search for the Higgs boson

September 12, 2012 Leave a comment

10 September 2012

The ATLAS and CMS experiments at CERN today published observations of a new particle in the search for the Higgs boson in the journal Physics Letters B.

The papers: “Observation of a new boson at a mass of 125 GeV with the CMS experiment at the LHC” and “Observation of a new particle in the search for the Standard Model Higgs boson with the ATLAS detector at the LHC” are freely available online on ScienceDirect.

“These papers present the first observations of a new particle discovered by two big experiments at the Large Hadron Collider (LHC) in the search for the Standard Model Higgs boson which has spanned many decades and has involved many experiments,” says CMS spokesperson Joe Incandela. “They are the most important papers to come from the LHC so far and the findings are key to the field of particle physics. We are very pleased to see them published in Physics Letters B, accessible to all who may want to read them.”

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CERN’s Large Hadron Collider Experiments Bring New Insight Into Matter of the Primordial Universe

ScienceDaily (Aug. 13, 2012) — Experiments using heavy ions at CERN’s Large Hadron Collider (LHC) are advancing understanding of the primordial Universe. The ALICE, ATLAS and CMS collaborations have made new measurements of the kind of matter that probably existed in the first instants of the Universe. They will present their latest results at the 2012 Quark Matter conference, which starts August 13 in Washington DC. The new findings are based mainly on the four-week LHC run with lead ions in 2011, during which the experiments collected 20 times more data than in 2010.

Heavy-ion collision recorded by ALICE in 2011. (Credit: CERN)

Just after the Big Bang, quarks and gluons — basic building blocks of matter — were not confined inside composite particles such as protons and neutrons, as they are today. Instead, they moved freely in a state of matter known as ‘quark-gluon plasma’. Collisions of lead ions in the LHC, the world’s most powerful particle accelerator, recreate for a fleeting moment conditions similar to those of the early Universe. By examining a billion or so of these collisions, the experiments have been able to make more precise measurements of the properties of matter under these extreme conditions.

“The field of heavy-ion physics is crucial for probing the properties of matter in the primordial Universe, one of the key questions of fundamental physics that the LHC and its experiments are designed to address. It illustrates how in addition to the investigation of the recently discovered Higgs-like boson, physicists at the LHC are studying many other important phenomena in both proton-proton and lead-lead collisions,” said CERN Director General Rolf Heuer.

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Higgs boson results from LHC ‘get even stronger’

August 3, 2012

Higgs announcement, 4 July
The announcement on 4 July was greeted with enthusiasm around the world

The particle has been the subject of a decades-long hunt as the last missing piece of physics’ Standard Model, explaining why matter has mass.

Now one Higgs-hunting team at the Large Hadron Collider report a “5.9 sigma” levels of certainty it exists.

That equates to a one-in-550 million chance if the Higgs did not exist, the team would see these same results.

The formal threshold for claiming the discovery of a particle is a 5-sigma level – equivalent to a one-in-3.5 million chance.

That is the level that was claimed by the team behind Atlas, one of the LHC’s Higgs-hunting experiments, during the 4 July announcement. The other, known as CMS, claimed results between 4.9 and 5 sigma.

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