So This Physicist Walks into a Bar...

by Judy Jackson

Picture your local watering hole. That’s where the Department of Energy’s Peter Rosen recommends field-testing the message of particle physics. Sidle up to “Joe and Janine Sixpack,” Rosen suggests, and lay some neutrinos on them. If the skimpy little particles don’t do it for the Sixpacks, see how they respond to superconducting magnet technology or the World Wide Web—whatever it takes to get the barroom buzzing over baryons.

Potential pick-up lines from particle physics made Rosen’s point about the need for improved physics communication, part of his remarks to Fermilab users at the 35th Users’ Annual Meeting, held at Fermilab on June 10 and 11. Also on the agenda: Fermilab Director Mike Witherell on the state of the laboratory, the Beams Division’s Dave McGinnis on the state of the Tevatron and Run II, and Fermilab users on the state of experiments and projects past, present and to come. Via videotape, Stanford Linear Accelerator Center Director Jonathan Dorfan led users on a brisk but comprehensive tour of SLAC science. Users discussed the perennial problem of what to do about falling federal funding for physics. Chez Léon chef Tita Jensen served a memorable dinner, and users ended the evening with what has become una bella tradizione at the Users’ Meeting: meatballs, cannoli and grappa at Festa Italiana in the Barn, hosted by Fermilab’s Italian delegation.

It was our annual reminder that Fermilab is not just a physics laboratory but a unique community of scientists.

Eyes on Run II

Concern for the progress of Run II at the Tevatron permeated the Users’ Meeting, as it does all of Fermilab. As the users met, the Fermilab Beams Division was winding up a two-week shutdown for the installation of new devices to raise the accelerator’s collision rate from what Witherell called Run II’s “disappointing start.”

Rosen reminded the audience how much is at stake.

“There is much interest in Washington as to the progress of Run II,” Rosen said. “It is essential for Run II to succeed. All of us on the outside are waiting for new physics results. Run II at the Tevatron is a key issue for the whole physics program.”

Witherell described efforts to raise the Tevatron’s collision rate, showing a plot of rising accelerator luminosity over recent months.

“Run II is the most important element of our program,” he said. “There has been much progress since March. Some solutions have been found. There are many more to go. The general strategy is to improve the antiproton efficiency, improve the proton intensity at low beta [where collisions occur], and improve the [antiproton] stacking rate. In October, we will integrate the Recycler. Every doubling of the data sample makes possible new possibilities and opens up a whole roster of new physics results.”

Run II at the Tevatron is a key issue for the whole physics program. –Peter Rosen

The Beams Division’s Dave McGinnis gave users still more specifics on the division’s ongoing push for higher luminosity.

“The Tevatron Department helix work has paid off,” McGinnis said, describing adjustments to the paths of particles orbiting the accelerator. “The big thing missing is the amount of pbars going to low beta. Only thirty percent of the pbars are getting through to collision. Are there enough pbars? Yes. There are plenty of pbars coming out of the Accumulator, but they are not making it to low beta. They are getting lost when they come out of the Main Injector and go into the Tevatron. The problem is interbeam scattering.”

McGinnis described three steps to fixing the problem: better helices, smaller beam size and bigger beam apertures. He said the current shutdown would lead to improved stochastic cooling for a smaller antiproton beam size and described a new “dual lattice” operation also designed to deliver more antiprotons to the collision points.

On the bride side

All was not low-luminosity angst. Rosen expressed “a note of confidence” in the laboratory, based on the turnaround in the NuMI construction project.

“A year ago, NuMI was in serious trouble,” Rosen said. “The laboratory has turned the project around, and now we all are confident that NuMI will succeed.”

Witherell concurred.

“The excavation of NuMI’s onsite tunnel is complete,” he said. “Two-hundred-twenty-five of the 486 planes of the MINOS detector are in place. The NuMI project management deserves much credit. Further, MiniBooNE is ready to go, with the first neutrinos right around the corner in July 2002.”

Users learned of progress on Fermilab’s contributions to the Large Hadron Collider at CERN. Witherell reported that the Fermilab-led U.S. program for the Compact Muon Solenoid detector at the LHC has begun to prepare for the transition from detector construction to the CMS research program. He noted that the US LHC accelerator program, also led by Fermilab is 73 percent complete, and has received excellent reviews.

E791, the gift that keeps on giving

Fixed-target experiments at Fermilab ceased taking data in 1999. Nevertheless, an overview of fixedtarget experiments by the University of Virginia’s Sasha Ledovskoy presented an astonishing number of recently published fixed-target results— including new results just published by E791, an experiment to study the decay of charm particles, which stopped taking data in 1991.

Along with reports from current experiments and proposed projects came consideration of the longer-term future of particle physics. Witherell cited the recently completed High Energy Physics Advisory Panel plan that proposed a linear collider in the US.

“There are many constraints on moving forward with the plan,” Witherell said, “with a federally imposed annual cap of $19 million in funding for linear collider R&D funding, including a cap of $3 million at Fermilab. When the government responds with more funding for linear collider R&D, that will be a sign that they are getting serious about responding to our field’s recommendations.”

Rosen described the formation of an international linear collider steering group that expects to meet in Amsterdam in July.

“How can we put the linear collider on a path to construction?” he asked. “We all recognize that the linear collider will be an international project from the word go. Governments need to find how they will work together. In this country, a strong group has been established to guide R&D and physics and to help make the case to the Sixpacks.”

Heads up, Joe and Janine. A linear collider may be coming soon to a barroom near you.