At CERN, the European Organization for Nuclear Research, physicists and engineers are probing the fundamental structure of the universe.
ATLAS is the name of the particle physics experiment and its corresponding detector at the CERN laboratory. CoEPP experimentalists work on this experiment directly, through shifts of working on the detector, and through data analysis and presentation.
The LHC - the biggest particle accelerator in the world.
The Large Hadron Collider (LHC) is the world's largest and highest-energy particle accelerator, intended to collide opposing particle beams of protons at an energy of 7 TeV (1.12 microjoules) per particle. It is expected that it will address the most fundamental questions of physics, hopefully allowing progress in understanding the deepest laws of nature. The LHC lies in a tunnel 27 kilometres (17 mi) in circumference, as much as 175 metres (574 ft) beneath the Franco-Swiss border near Geneva, Switzerland.
The Large Hadron Collider (LHC) is gearing up for its second three-year run. The LHC is the largest and most powerful particle accelerator in the world and the whole 27-kilometre superconducting machine is now almost cooled to its nominal operating temperature of 1.9 degrees above absolute zero. All teams are at work to get the LHC back online and the CERN Control Centre is in full swing to carry out all the requested tests before circulating proton beams again in March 2015. Run 2 of the LHC follows a 2-year technical stop that prepared the machine for running at almost double the energy of the LHC’s first run.
“With this new energy level, the LHC will open new horizons for physics and for future discoveries,” said CERN Director General Rolf Heuer. “I’m looking forward to seeing what nature has in store for us”.
The Large Hadron Collider was built by the European Organization for Nuclear Research (CERN) with the intention of testing various predictions of high-energy physics, including the existence of the hypothesized Higgs boson and of the large family of new particles predicted by supersymmetry. It is funded by and built in collaboration with over 10,000 scientists and engineers from over 100 countries as well as hundreds of universities and laboratories.
On 9 December 2014, for the first time after the long shutdown, the magnets of one sector of the LHC, one eighth of the ring, were successfully powered to the level needed for beams to reach 6.5 TeV, the operating energy for run 2. The goal for 2015 will be to run with two proton beams in order to produce 13 TeV collisions, an energy never achieved by any accelerator in the past.
“After the huge amount of work done over the last two years, the LHC is almost like a new machine,” said CERN’s Director for Accelerators and Technology Frédérick Bordry. “Restarting this extraordinary accelerator is far from routine. Nevertheless, I’m confident that we will be on schedule to provide collisions to the LHC experiments by May 2015”.
ALICE, ATLAS, CMS and LHCb, the four large experiments of the LHC, are also undergoing major preparatory work for run 2, after the long shutdown during which important programmes for maintenance and improvements were achieved. They will now enter their final commissioning phase.
The Higgs boson
As ICHEP (International Conference on High Energy Physics) 2012 launched on July 4, CERN announced by webcast to Melbourne that "In layman's terms, I think we've found it". Those were the words of Prof Rolf Heuer, Director General of CERN, and the 'it' was the elusive Higgs particle.
Referred to as the 'God particle', the announcement from physicists at the Large Hadron Collider confirmed the compelling evidence of Higgs within the testing parameters, sparking media excitement worldwide. ATLAS and CMS researchers had observed a new particle in the mass region around 126 GeV. This particle is consistent with the Higgs boson predicted by the Standard Model.
The Higgs boson, as proposed within the Standard Model, is the simplest manifestation of the Brout-Englert-Higgs mechanism. Other types of Higgs bosons are predicted by other theories that go beyond the Standard Model.
Fabiola Gianotti, speaking for the ATLAS experiment at CERN, confirmed the high consitency but stressed there was a lot more work to be done. CoEPP physicists will continue to be involved as this new phase develops.
(ICHEP 2012 Higgs update seminar and announcement of discovery)
On 8 October 2013 the Nobel prize in physics was awarded jointly to François Englert and Peter Higgs "for the theoretical discovery of a mechanism that contributes to our understanding of the origin of mass of subatomic particles, and which recently was confirmed through the discovery of the predicted fundamental particle, by the ATLAS and CMS experiments at CERN's Large Hadron Collider."