RHIC's future looks bright

Bertram Schwarzschild's Issues and Events piece on the National Research Council's report Revealing the Hidden Nature of Space and Time (PHYSICS TODAY, June 2006, page 26) states, "Fermilab's Tevatron is unlikely to outlive the decade. Neither is the PEP-II asymmetric electron–positron collider at SLAC nor the Relativistic Heavy Ion Collider at Brookhaven National Laboratory."

Placing RHIC in this context is odd since the NRC report nowhere mentions it. RHIC is funded by the Office of Nuclear Physics in the US Department of Energy's Office of Science, not by the Office of High Energy Physics, for which the NRC committee was charged with recommending priorities for the next 15 years.

More important, the notion that RHIC is "unlikely to outlive the decade" is misbegotten. The scientific impact of RHIC has been outstanding; its discovery of the "perfect liquid" of quarks and gluons was named the number-one physics story of 2005 by the American Institute of Physics publication Physics News Update and garnered media coverage around the world.

Brookhaven National Laboratory is currently working with the Office of Nuclear Physics to implement for RHIC a strategy for the period 2006–11 aimed at a 10-fold luminosity upgrade and detector upgrades. This strategy will place RHIC at the forefront of research in high-temperature quantum chromodynamics (QCD) for at least another 10 years. Furthermore, RHIC is the first and only hadron collider with the ability to accelerate, store, and collide polarized protons at energies up to 500 GeV in the center-of-mass frame. It therefore provides unique opportunities to study the spin content of the nucleon—a program that also will extend into the next decade.

Beyond that is the prospect of using RHIC as the basis for a polarized electron–ion collider, an option for an international next-generation facility for the study of QCD. That option will be discussed by the Nuclear Science Advisory Committee in 2007 as it develops its long-range plan for the field. If longevity is based on compelling science to be done, such a QCD facility—with ion–ion, proton–ion, polarized proton–proton, polarized electron–proton, and electron–ion collisions at high energy—would likely outlive the next decade.