CERN
restarts Hadron Collider after two years of repairs Scientists at Europe’s particle physics research centre Cern just outside Geneva restarted their “Big Bang” Large Hadron Collider (LHC) , embarking on a new bid to resolve some mysteries of the universe and look for “dark matter”. The machine had been shut for two years for a refit. Hopes for the second run lie in breaking out of what is known as the “Standard Model” of how the universe works at the level of elementary particles, and into “New Physics”. That includes searching for the dark matter that makes up about 96 per cent of the stuff of the universe but can only be detected by its influence on visible matter like galaxies and planets. The overhaul included new magnets, much higher energy beams and voltages and a complete check of all wiring around the underground 27km (17-mile) LHC tunnel and its four major detectors and multiple magnets. “It’s fantastic to see it going so well after two years and such a major overhaul,” Cern director general Rolf Heuer said on the research organization’s live blog for the restart. By June 2015 Cern will start smashing particles into each other in the LHC with nearly twice the energy compared with that first run from 2010-2013, and as before at close to the speed of light. The LHC comprises a 27-kilometre (17-mile) ring-shaped tunnel straddling the Franco-Swiss border, in which two beams of protons are sent in opposite directions. Powerful magnets bend the beams so that they collide at points around the track where four laboratories have batteries of sensors to monitor the smash ups. The sub-atomic rubble is then scrutinised for novel particles and the forces that hold them together. With its capacity to smash particles together at almost the speed of light and at a collision energy twice that of its first run, scientists hope that the revamped LHC will produce evidence of what has been dubbed “New Physics”. Among elements of this concept are the “dark matter” thought to make up some 96 per cent of the stuff of the universe while being totally invisible, and super-symmetry, or SUSY, under which all visible particles have unseen counterparts. “If I had to bet on what we will find, I would go for SUSY,” said Oliver Buchmueller, a scientist on one of the four machines around the ring that records each collision. “But we could also find something very, very unexpected,” he added. “This is what makes life on the energy frontier so exciting.” In 2012, the LHC discovered the Higgs Boson, the particle that confers mass, earning the Nobel prize for two of the scientists who, back in 1964, had theorised its existence. “The LHC will be running day and night. When we will get results we don’t know. What is important is that we will have collisions at energies we’ve never had before,” said Arnaud Marsollier, a Cern spokesman.
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