Sir

I read with great interest Colin Macilwain's News report “Budget crisis forces hard choices on US high-energy physics” (Nature 404, 909; 2000). The report goes a long way in describing the general situation of high-energy physics in the United States. Readers may, however, get the wrong impression, both as to its present intellectual health (despite the severe blow of losing the Superconducting Super Collider in 1993), and as to the efforts being made to get back on track — as the cartoon accompanying the article so dramatically displays.

High-energy physics here is very vigorous, with activity continuing at the Tevatron (Fermilab), activities under way in neutrino physics, use of the new B-Factory and the development of very large detectors to be used at the large hadron collider in CERN.

New facilities being contemplated include an electron–positron linear collider, a very large hadron collider and a neutrino factory. These facilities address very different aspects of high-energy physics. They are not in competition; they all should be built and — with sufficient international cooperation and an adequately long time frame — they will all be built.

The community, working with international colleagues, is developing a suitable plan for high-energy physics. Arriving at a well-thought-out and widely accepted programme for the future is expected to take a few years; a significant step will be undertaken at a retreat next summer.

With regard to budget realities, a neutrino factory may be attractive as a first step: it fits on several existing sites, it would be of worldwide interest, the accelerator cost can be balanced with detector costs and it can be staged. It would also go a long way towards demonstrating the technologies needed for a possible future muon collider. As we are still improving the design, it is premature to say if it will ultimately cost more or less than the $1 billion stated in your article. However, our first-draft design could be built in a few increments, each one costing under $1 billion, and each addressing new, and most interesting, physics.