The Large Hadron Collider
Sept. 9: Scientists at Cern are drawing up plans to scrap the giant Large Hadron Collider (LHC) that found the Higgs boson, and replace it with an even bigger machine designed to hunt down more exotic particles.
One idea is to remove the £3-billion particle accelerator and build a more powerful one in the same tunnels under Geneva in Switzerland.
Another is to build an entirely new accelerator up to 50 miles in circumference, three times the size of the LHC.
Such a machine is likely to cost several billion pounds, shared between Cern’s 20-member states, and would likely be built sometime after 2025.
It follows Cern’s July announcement that it may have had found the elusive Higgs boson, the fundamental particle that gives matter its mass.
The idea that such a particle might exist was put forward by Peter Higgs, emeritus professor of physics at Edinburgh University, in 1964.
He is now 83 years old and many physicists hope that he, along with Cern and perhaps fellow physicist Francois Englert, 79, whose own 1964 paper broke similar ground, will be rewarded with a Nobel prize this autumn.
However, they are also concerned about the 44 years that elapsed between Higgs’s proposal and the construction of a machine capable of finding his particle — which is why they are already drawing up plans for the LHC’s successor.
The designs for a new machine are in a paper written by 18 scientists, including John Ellis, Cern’s former head of theoretical physics.
It said: “The new machine could be installed in the LHC tunnel.… Alternatively, it could be installed in a new, longer tunnel, using a tunnel circumference of 80km.”
The suggestion will be discussed by the European Strategy Preparatory Group, in Cracow, Poland, this week.
Jon Butterworth, professor of physics at University College London, who represents Britain on the group, said that finding the Higgs was just the beginning. “It means we have a wild new frontier of physics to explore. Now we need to find out far more about it. “We can do some of that work by upgrading the LHC, but in the end it will need a more powerful machine.”
The timescale and technological challenges are huge. The LHC was first proposed in 1983 and was finally built in 2008. Much of that delay was because of the cutting-edge technologies that had to be developed to control and focus a tiny beam of particles packed with the energy punch of a car travelling at 1,600 mph.
James Gillies, Cern’s spokesman, said the LHC would shut down next spring for a two-year upgrade to increase its power. “It could do years of ground-breaking physics after that, but eventually we will need something more powerful,” he said.
Such a machine might help resolve some of the questions raised by Einstein, who could not reconcile the forces operating at the level of atoms with the force of gravity which governs the movement of stars and planets.
He spent much of his career trying to find a “a grand unified theory” that would reconcile the two. The problem has still not been solved.
The most immediate question for physicists is who might be in line for a Nobel prize over the Higgs discovery — with a possibility that the summer dubbed Britain’s “greatest ever” for its sporting achievements could be followed by an autumn in which two of its physicists win the world’s top academic awards.
Higgs is the obvious candidate, but he was beaten into print in 1964 by Englert and Robert Brout, both Belgian, who put forward a similar theory albeit without predicting a particle.
Brout died last year, but there are also three other physicists, Tom Kibble, of Imperial College London, and Americans Gerry Guralnik and Dick Hagen, who jointly published a similar idea soon after — with Kibble going on to build the experimental model on which the LHC was based.
Frank Close, professor of physics at Oxford University, has lobbied for the prize to be shared between Higgs, Kibble and Englert.
He wrote: “These scientists have been waiting 48 years, and hopefully the Nobel committees will not delay further.”