Large Hadron Collider

LHC experiments bring new insight into primordial universe

Geneva, 26 November 2010. After less than three weeks of heavy-ion running, the three experiments studying lead ion collisions at the LHC have already brought new insight into matter as it would have existed in the very first instants of the Universe’s life.

The ALICE experiment, which is optimised for the study of heavy ions, published two papers just a few days after the start of lead-ion running. Now, the first direct observation of a phenomenon known as jet quenching has been made by both the ATLAS and CMS collaborations. This result is reported in a paper from the ATLAS collaboration accepted for publication yesterday in the scientific journal Physical Review Letters.

A CMS paper will follow shortly, and results from all of the experiments will be presented at a seminar on Thursday 2 December at CERN. Data taking with ions continues to 6 December.

Read the full article from CERN here

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Researchers at the Large Hadron Collider (LHC) are getting set to create the Big Bang on a miniature scale.

Researchers at the Large Hadron Collider (LHC) are getting set to create the Big Bang on a miniature scale.

Since 2009, the world’s highest-energy particle accelerator has been smashing together protons, in a bid to shed light on the fundamental nature of matter.

But now the huge machine will be colliding lead ions instead.

The experiments are planned for early November and will run for four weeks.

The LHC is housed in a 27km-long tunnel on the Franco-Swiss border and is managed by the European Organization for Nuclear Research (Cern).

The collider consists of four different experiments and one of them, ALICE, has been specifically designed to smash together lead ions.

The goal of these collisions is to investigate what the infant Universe looked like. Colliding protons at high energies was aimed at other aspects of physics, such as finding the elusive Higgs boson particle and signs of new physical laws, such as a framework called supersymmetry.

Cern’s spokesman James Gillies told BBC News that besides ALICE, the ATLAS and Compact Muon Solenoid (CMS) experiments will also be temporarily colliding ions.

Big Bang

He said the tests could provide an insight into the conditions of the Universe some 13.7 billion years ago, just after the Big Bang.

They will look at the Universe fractions of a second after a tiny but very dense ball of energy exploded to create the cosmos as we know it today.

Continue reading the main story

“Start Quote

At the temperatures generated, even protons and neutrons will melt, resulting in a hot dense soup of quarks and gluons”

End Quote David Evans University of Birmingham, UK

Scientists believe that it was back then that a special state of matter existed, different from the matter the Universe is formed of now.

“Matter exists in various states: you can take a material like water and if you deep freeze it, it’ll be solid, and if you put it on a table, it’ll turn into a liquid, and if you put it into a kettle, it’ll turn into a gas,” said Dr Gillies.

“It’s all the same stuff, but those are different states of matter. And if you take materials into laboratories, you can pull the electrons off the atoms and you have another state of matter which is called plasma.”

But at the very beginning of the Universe, there might have been yet another state of matter. Physicists have dubbed this “stuff” the quark-gluon plasma.

“And this is the state of matter you have if you’re able to effectively melt the nuclear matter that makes up atoms today, releasing the things that are inside, which are quarks and gluons,” Dr Gillies explained.

read the full article here

Monday, November 8th, 2010 Big Bang Machine, CERN, Large Hadron Collider, LHC Comments Off on Researchers at the Large Hadron Collider (LHC) are getting set to create the Big Bang on a miniature scale.

CERN completes transition to lead-ion running at the LHC

Four days is all it took for the LHC operations team at CERN to complete the transition from protons to lead ions in the LHC. After extracting the final proton beam of 2010 on 4 November, commissioning the lead-ion beam was underway by early afternoon. First collisions were recorded at 00:30 CET on 7 November, and stable running conditions marked the start of physics with heavy ions at 11:20 CET today.

“The speed of the transition to lead ions is a sign of the maturity of the LHC,” said CERN Director General Rolf Heuer. “The machine is running like clockwork after just a few months of routine operation.”

source CERN

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CERN – potential new discovery spotted by Atom smasher scientists

GENEVA — Scientists at the world’s biggest atom smasher said Tuesday they appeared to have discovered a previously unobserved phenomenon in their quest to unravel the deepest secrets of the universe.

Results from one of the detectors in the Large Hadron Collider experiment indicated that “some of the particles are intimately linked in a way not seen before in proton collisions,” the European Organisation for Nuclear Research (CERN) said on its website.

“The new feature has appeared in our analysis around the middle of July,” physicist Guido Tonelli told fellow CERN scientists at a seminar to present the findings from the collider’s CMS (Compact Muon Solenoid) detector.

“We have today submitted a paper to expose our findings to the wider (scientific) community,” he added, underlining caution and the need for the peer review outside CERN.

Nonetheless, Tonelli, a physicist from Italy’s University of Pisa and scientific spokesperson for the CMS detector, underlined that during weeks of cross-checks and critical debate among the team, “we didn’t succeed to kill it.”

The phenomenon showed up as a “ridge-like structure” on computer mapping graphs based on data from billions of proton collisions in the 3.9-billion-euro (5.2-billion-dollar) machine.

The 27-kilometre (16.8-mile) circular particle accelerator buried under the French-Swiss border is recreating powerful but microscopic bursts of energy that mimic conditions close to the Big Bang that created the universe.

The CMS, one of six experiments around the accelerator, is designed to search for for the elusive and so far theoretical Higgs Boson, commonly nicknamed the “God Particle”.

It is also aimed at shedding light on components of dark matter, the mysterious invisible void that makes up 26 percent of the universe.

MIT physicist Gunther Roland, one of the authors of the paper submitted for review, described the latest observation as a “a subtle effect in a complex environment — careful work is needed to establish its physical origin.”

“What we really hope to get is not just ideas, but how to test it,” he added during the seminar at CERN’s headquarters on the edge of Geneva.

The organisation said it bore “some similarity” with observations in a smaller Ion collider at the US Department of Energy?s Brookhaven National Laboratory.

Despite applause from their peers at CERN, the CMS team’s interpretation of the observation on Tuesday was vigorously challenged during the meeting as scientists bounced suggestions off each other.

“We are stating facts, facts that there is something that we have not seen before,” Tonelli responded, as they began the process of seeking endorsement and an explanation for the observation.

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