HEPAP Recommendations for the Future of U.S. High Energy Physics

As reported in FYI #33 , at a February 18-19 meeting of DOE’s High Energy Physics Advisory Panel (HEPAP), Subpanel Chairman Fred Gilman presented his group’s recommendations for the future of the High Energy Physics program over the next decade. The report considers three funding scenarios over the ten-year period: a constant-level-of- effort case, where the budget keeps abreast of inflation; a modest decrease in funding; and a modest increase in funding. The Subpanel found that even with constant funding, “difficult choices [were] required to end some programs and enable funding to be redirected to top priorities.”

The Subpanel was guided by the following principles: (1.) Maximize the potential for major discoveries by utilizing existing U.S. forefront facilities to capitalize on prior investments and by participating in experiments at unique facilities abroad; (2.) Position the U.S. program for a long-term leading role at the energy frontier through vigorous research and development on possible future facilities and international collaboration on future machines; and (3.) Prepare the next generation of scientists through education and training at universities and laboratories.

The report’s main emphasis is focused on the constant-level-of- effort funding case, as are the recommendations below:

Recommendation on the Effective Utilization of Facilities: “The Subpanel places its highest priority on optimum utilization of the forefront facilities nearing completion. The Subpanel recommends that funding for [the] Tevatron collider, PEP-II, and CESR operations, and for the physics groups using them, be at a level that ensures these facilities fulfill their physics potential.”

Recommendation on the LHC: “The Subpanel strongly endorses the physics goals of the LHC and U.S. participation in the accelerator project and the ATLAS and CMS experiments. The funding level and schedule contained in the CERN-U.S. LHC agreement should be followed....”

Recommendation on Planning for Future Facilities: “The Subpanel recommends that a new facility at the energy frontier be an integral part of the long-term national high-energy physics program.”

Recommendation on R&D for a Linear Collider: “The Subpanel recommends that SLAC continue R&D with Japan’s KEK toward a common design.... This is not a recommendation to proceed with construction. A decision on whether to construct a linear collider should only follow the recommendation of a future subpanel convened after the CDR is complete....”

Recommendation on R&D for a Muon Collider: “The Subpanel recommends that an expanded program of R&D be carried out on a muon collider, involving both simulation and experiments.... The scale and progress of this R&D program should be subject to additional review in about two years.”

Recommendation on R&D for a Very Large Hadron Collider: “The Subpanel recommends an expanded program of R&D on cost reduction strategies, enabling technologies, and accelerator physics issues for a VLHC.... The scale and progress of this R&D program should be subject to additional review in about two years.”

Recommendation on the Level of Funding for the University-Based Program: “An important part of the charge concerned the university-based high-energy physics program and its optimization within the overall plan for the next decade. The Subpanel intensively examined the status of high-energy physics research at universities and...recommends that, over a two-year period, the annual DOE operating funds for the university program be ramped up by a total of 10% above inflation. The Subpanel encourages the NSF to make a similar increase in its experimental and theoretical elementary particle physics programs. These increases should be used for activities judged to have the largest impact on physics goals and student training. This would partially restore the losses of the last five years and better prepare university groups to use the new facilities.”

Additional Recommendations include a luminosity upgrade to the Tevatron during the first half of the next decade; due to budget constraints, only one of the two large detectors should be upgraded to match the increased luminosity. Any new energy frontier machine should be considered as an integral part of a national program, not just specific to an individual laboratory program. The non-accelerator experimental component of the HEP program should be strengthened. Collaborations should be encouraged between university programs and national laboratories. Also, on a trial basis, direct comparative reviews of university groups should be instituted to ensure an optimal distribution of resources.

Under the constant-level-of-effort case, the Subpanel found the highest priority items to be: effective use of the facilities nearing completion; preparation for the LHC; R&D needed to build a future frontier facility; and partial restoration of the strength of university groups. A number of sacrifices were identified in order to fund the higher priorities, including dramatically reducing Brookhaven’s HEP program after the AGS is transitioned to Nuclear Physics; upgrading only one of the two large collider detectors at Fermilab in the next decade; performing only a small number of experiments on CP violation and rare decays; and realizing only a few large non-accelerator initiatives.

Under the Declining Budget scenario, the Subpanel had the following recommendation: protect, to the extent possible, the highest priority items. “Everything else in the program,” the report warns, " would be reduced or eliminated.”

For the Increased Budget scenario, the Subpanel considered the situation where support would be doubled over a ten-year period, “as the leaders of many scientific and engineering societies recently proposed for the nation’s research budget.” In this case, according to the report, “the U.S. would be able to move forward with full exploration and development of the technologies for the next major accelerator...support for university-based research would be increased to the level appropriate to reap the scientific benefits of the enhanced program...the discovery potential of existing facilities could be more fully exploited,” and the U.S. would be able to “maximize the scientific return on the facilities now being completed [and take] a leading role in initiating the next major international collider at the energy frontier.”