CU physicists ascend on Snowmass to make case for role in big collider

By David Brand

Cornell sent a large physics contingent to the mountain community of Snowmass Village, Colo., this month to present the university's case for being a major player in the world's next large particle accelerator, a $6 billion-plus colossus that will require unprecedented international scientific cooperation.

Attending the high-energy physics meeting at Snowmass Village, Colo., last week were Cornell physics faculty, from left, Lawrence Gibbons, assistant professor; David Cassel, associate director of the Floyd R. Newman Laboratory for Nuclear Studies; Richard Galik, professor; and Joseph Rogers and Ritchie Patterson, both associate professors. Fred Ullrich/Fermilab

And because change is in the air at Cornell's Newman Laboratory of Nuclear Studies (LNS), the reception to Cornell's bid was enthusiastic.

The meeting, which lasted from July 1 to July 20, was attended by nearly 900 physicists from institutions around the world, and the major focus was on the massive linear collider, perhaps 20 miles across, that would explore such fundamental details as the origin of the universe, the structure of space and the nature of matter itself. The consensus at the end of the meeting last week was that the linear collider should be built. The next stage is to convince governments to provide the funding.

"We are determined to play a major role in the next linear collider," said Maury Tigner, director of LNS, which operates the Cornell Electron Storage Ring (CESR) and its CLEO III particle detector.

Not only has the design not yet been chosen for the huge machine, but the location -- even the country -- has yet to be selected. Germany, Japan and the Stanford Linear Accelerator Center (SLAC) have presented the three leading competing designs. Cornell is one of the 40 institutes from 10 countries making up the collaboration that is developing the German design, called TESLA. Indeed, the TESLA design was conceived at Cornell, and the first superconducting cavities (for accelerating particles) to meet TESLA specifications were made at the university. However, said Tigner, "We are technology neutral in the sense that we will be willing to participate in any design."

The Snowmass meeting, held just outside Aspen, has been held at intervals since 1982 and was instrumental in the development of the Superconducting Supercollider, eventually killed by Congress, and in 1988 in defining the so-called b-physics program at LNS, on which CESR's and CLEO's reputation largely rests. The last conference was held in 1996.

Research at LNS has long involved the two different classes of particle, called quarks and leptons, from which all matter is composed. Quarks come in various types, or "flavors," including up, down, charm (c-quark), strange, top and bottom (b-quark). Combinations of a quark and anti-quark form particles called mesons.

The lightest particle that contains the bottom quark, or b-quark, is called the B meson, and in a topsy-turvy way, the best method for finding information about the b-quark is to study the B meson. During the 1990s, research at CESR and CLEO provided much of the world's knowledge about the nature of the weak nuclear force -- one of nature's four fundamental forces -- through the study of the b-quark.

A year ago, LNS was confronted by masses of data on b-physics coming from two new, highly advanced particle accelerators at SLAC and Japan's KEK. In response to this competition, LNS has started to formulate a new research plan, by which it would go from the b-quark to the c-quark. Under this plan, which largely sprang from a workshop at Cornell in May attended by the 19 universities that collaborate in CLEO, CESR would operate at lower energies to investigate charm, or c-physics.

At Snowmass, David Cassel, associate director of LNS, noted that Cornell would be in a strong position to obtain the type of charm data that will be necessary to investigate the most fundamental -- and elusive -- particle of all, the Higgs boson, theorized to be the source of all weight and mass in the universe. "This is a unique opportunity for a major lab to begin running at low energies to obtain this data," he said.

The LNS plan to investigate c-physics was widely discussed and debated at the Snowmass conference and Cornell physicists said the response was overwhelmingly enthusiastic. The reason is not only that the charm physics data produced will be valuable for research programs, but also that the technology used in obtaining the data will be vital for the proposed large collider.

Joseph Rogers, Cornell associate professor of physics, explained that it will be necessary to outfit CESR with about 14 large magnets, called wigglers, to help stabilize the particle beam at reduced energy. Wigglers are widely used to create concentrated X-ray radiation for labs for structural and biological research, such as the Cornell High-Energy Synchrotron Source. But they have not been used before as the main generator of X-ray radiation in particle colliders. However, the wigglers that will be used at CESR are nearly identical to those being proposed for the large collider. "These will be prototype wigglers in the sense that they will be used in a way not seen before," Rogers said. "So we think we can make a significant technological contribution to the linear collider."

Cornell also would contribute to the program being created by an international panel to commission, operate and use the collider. Called the Global Accelerator Network, the system would allow the operation of the collider over the web from anywhere in the world. Cornell physics professor Donald Hartill is a member of the panel developing the network.

Indeed, said Ritchie Patterson, associate professor of physics at Cornell, LNS's plans generated wide excitement at Snowmass. "It looks as if we at Cornell have made an impression on the physics community that we have an important role to play in the new collider," she said.