ROME—The Italian government has scrapped plans to build a particle accelerator known as SuperB in the outskirts of Rome after a new study calculated its total cost to be about €1 billion—some €350 million more than previously estimated.
SuperB was to have been built on the campus of the University of Rome Tor Vergata to the south of the Italian capital by an international collaboration of scientists. It was to have consisted of two 1.2-kilometer-circumference rings that would have accelerated beams of electrons and positrons. Collisions between the beams would have allowed the study of extremely rare phenomena in the decay of B mesons and other exotic particles. That could help explain why the universe seems to be so dominated by matter, as opposed to antimatter.
Some physicists were skeptical that cash-strapped Italy could afford to pay for such a machine. The Italian government said that it would provide €250 million of the €650 million budget, while other countries, including France and Russia, said they might pay a share of the costs. The United States, meanwhile, agreed to donate parts from its decommissioned PEP-II/BaBar "B-factory" at the SLAC laboratory in California for use in SuperB. But it was not clear where the roughly €200 million for the first 10 years of operation would have come from.
The latest cost estimate of about €1 billion now appears to have sunk the project. The estimate came in a report prepared by an international commission chaired by Gabriele Fioni of the French atomic and alternative energy agency CEA, drawing on a detailed analysis carried out by the SuperB collaboration itself. According to a press release from Italy's National Institute of Nuclear Physics (INFN), research minister Francesco Profumo studied the commission's report on Tuesday and discussed its contents with the heads of the INFN and Cabibbolab, the organization set up to house the collider. "The minister pointed out that the importance and the quality of the programme were not in dispute," the press release continued, "but that the country's economic conditions and the limits set by the National Research Plan were incompatible with the estimated costs of the project."
Collaboration member David Hitlin of the California Institute of Technology in Pasadena explains that the higher price tag was due in part to the fact that the site for the accelerator complex was changed after the original cost estimate had been made—from INFN's laboratory in Frascati, also south of Rome, which would have had power, cooling water, and other necessary utilities already partly in place, to Tor Vergata, which did not.
Hitlin also says that there had been an underestimation of the costs needed to make both the tunnels' foundations and the accelerator itself stable enough to ensure the collision of very narrow beams—which were required to generate high-intensity collisions while keeping power consumption within reasonable limits. In addition, he says, some of the magnets from the old American machine were found to be not well-suited to the Italian design, so extra funding would have been needed to build new magnets.
"I am extremely disappointed," Hitlin says. "SuperB's science is first class and would allow unique studies that may now never get done." He argues that the collider would have had a number of important advantages over a rival Japanese machine, an upgraded version of the Belle experiment at the KEK laboratory, including a higher collision rate and a linearly polarized electron beam that would have allowed novel studies of the fundamental particles known as tau leptons.
The decision to ditch SuperB had a silver lining for physicists, however. The Italian government invited INFN to pitch proposals for new projects that could be funded with the €250 million originally promised for SuperB. Hitlin says that "the obvious step is to study a smaller, cheaper ring at a lower energy" that would be suited to studying the decay of tau leptons and particles containing so-called charm quarks, rather than the heavier B mesons. Such a facility might be of interest to some scientists in the current collaboration, Hitlin says, but not to others.
INFN has set up two committees to evaluate the feasibility of this lower-energy machine—one to analyze its scientific potential and the other to analyze its costs—and a third committee to study alternative facilities. These evaluations are due to be completed by Christmas. INFN President Fernando Ferroni tells ScienceInsider that he hopes "the countries that have already declared themselves partners of the SuperB project and possibly others" will take part in building the new machine.