Published online 11 January 2011 | Nature 469, 141 (2011) | doi:10.1038/469141a
Corrected online: 12 January 2011

News

Tevatron faces final curtain

Particle accelerator to be switched off this year, as lack of funds spells the end for US bid to capture Higgs particle.

The Tevatron’s 6.3-kilometre-long ring will stop colliding particles this year rather than in 2014.Fermilab

Depending on who you talk to, it is either a disappointing blow or a clean break heralding an exciting new era. After much debate, officials at the US Department of Energy's Office of Science revealed this week that they have decided not to extend funding for the Tevatron, the proton–antiproton collider at Fermilab in Batavia, Illinois, by an additional three years. The decision means that the first glimpse of the long-predicted Higgs particle, thought to endow other particles with mass, will probably be achieved by the Large Hadron Collider (LHC) at CERN, Europe's particle-physics lab near Geneva in Switzerland.

The decision was explained in a letter sent on 10 January by Bill Brinkman, director of the Office of Science, to Melvyn Shochet, a physicist at the University of Chicago, Illinois, and chairman of the energy department's High Energy Particle Advisory Panel (HEPAP). In October 2010, with the LHC suffering from delays, HEPAP had recommended that the US machine be extended beyond its planned 2011 closure if extra funding of US$35 million could be found. It couldn't, says Brinkman. "Unfortunately, the current budgetary climate is very challenging and additional funding has not been identified," he writes in his letter. He adds that the Tevatron will shut down this year as planned.

The decision is a blow for the 1,200 physicists who work on experiments at the Tevatron, the world's second most powerful accelerator after the LHC, as well as for particle-physics theor­ists at Fermilab and elsewhere who would have enjoyed working with the data. "I feel disappointed," says Pier Oddone, Fermilab's director. "We all would have wanted to see the Tevatron continue."

Rick Van Kooten of Indiana University Bloomington, who recommended the extension to the Tevatron in his role as chairman of Fermilab's Physics Advisory Committee, says he's also disappointed at the decision, but is convinced that sincere efforts were made to find the funding.

“I’m glad they made a clean, unambiguous decision. One concern was a drawn-out process.”


Leaders of Tevatron experiments made the case for extension last year, arguing that the machine's smooth running, combined with technical problems at the LHC, provided the Tevatron with a shot at discovering the Higgs, and the glory that would go with it. The two advisory panels also agreed that the physics case was compelling. But Charles Baltay, a physicist at Yale University in New Haven, Connecticut, and the chairman of P5, the HEPAP subpanel that considered the request, says this week's decision not to go ahead is consistent with the P5 recommendation that the Tevatron extension be funded only by adding to the high-energy physics budget, and not by taking funds away from other US particle-physics experiments. "I'm glad they made a clean, unambiguous decision," he says. "One concern was a drawn-out process."

In a way, the decision can be seen as a vote of support for a programme mapped out by P5 in 2007 and 2008. According to that programme, the United States should concede the realm known as the 'energy frontier', involving the highest-energy particle collisions, to the LHC, instead focusing its domestic efforts on 'the intensity frontier', achieving the greatest number of particle collisions per second. The latter is ideal for studying rare pro­cesses, and so P5 recommended investment in a slew of experiments to do just that. They include Fermilab's Mu2e, which will look for evidence of neutrino-less conversion of muons to electrons, and NOνA and the Long Baseline Neutrino Experiment, which will pin down the mass and other properties of elusive neutrinos, expected to have relevance for explaining the asymmetry between matter and antimatter in the Universe.

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Mark Messier of Indiana University Bloomington, co-spokesman for NOνA, says the decision makes things easier for experiments that would have competed for resources had the extension been approved. "We're back on the original course. There's something that we now don't have to deal with," he says. The Tevatron extension would have delayed the start of NOνA, because the neutrino experiment is designed to use the Tevatron's cast-off recycler, a particle-storage ring.

Robert Roser, co-spokesman for one Tevatron experiment, the Collider Detector at Fermilab, says that physicists on the experiment will now focus on ensuring the most successful end to the current run. "We raised the bar for the LHC. We're very proud of our accomplishments." The analysis of data from the machine is expected to continue for the next two to three years.

Oddone says that the exact switch-off date will become clear once the US Congress passes the fiscal year 2011 budget. 

Corrected:

This story originally characterized the Mu2e experiment as studying the decay of muons to electrons. It will, in fact, look for evidence of neutrino-less conversion of muons to electrons. The text has been revised to reflect this.

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  • #61807

    I am still confused. A hydrogen atom has mass, but the mass of the particle spiky statistical wave thingy that gives it mass is many times it's mass.

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