ICFA Statement on Linear Colliders February 2004

13 February 2004

ICFA Statement on Linear Colliders

ICFA welcomes the January 2004 OECD Ministerial Statement on International Cooperation on Large Accelerator-based Projects in High-Energy Physics, which “acknowledged the importance of ensuring access to large-scale research infrastructure and the importance of the long-term vitality of high-energy physics They noted the worldwide consensus of the scientific community, which has chosen an electron-positron linear collider as the next accelerator-based facility to complement and expand on the discoveries that are likely to emerge from the Large Hadron Collider currently being built at CERN. They agreed that the planning and implementation of such a large, multi-year project should be carried out on a global basis, and should involve consultations among not just scientists, but also representatives of science funding agencies from interested countries. Accordingly, Ministers endorsed the statement prepared by the OECD Global Science Forum Consultative Group on High-Energy Physics (see Appendix).”


In 1999 ICFA issued a statement on Linear Colliders, noting that scientific panels charged with studying future directions for particle physics in Europe, Japan, and the United States have concluded that there would be compelling and unique scientific opportunities at a linear electron-positron collider in the TeV energy range. Such a facility is a necessary complement to the LHC hadron collider now under construction at CERN.

As a consequence, at that time ICFA recommended continued vigorous pursuit of the accelerator research and development on a linear collider in the TeV energy range, with the goal of having designs complete with reliable cost estimates within a few years.

Since 1999 major progress has been made in several key areas:

Science: In 2001-2002, the three regional organizations of the HEP community (ACFA in Asia, HEPAP in North America, and ECFA in Europe) have reached the common conclusion that the next accelerator should be an electron-positron linear collider with an initial centre-of-mass energy around 500 Giga-electronvolts (GeV), later upgradable to higher energies, and that it should be built and operated in parallel with the Large Hadron Collider under construction at CERN. In January 2004, the ECFA, ACFA and HEPAP Chairs, in communications to the ICFA Chair, reaffirmed their community’s priorities as formulated in 2001-2002. In addition, the scientific case has recently been published in a tri-regionally based consensus paper ‘Understanding Matter, Space and Time’. So far, this document has been signed by more than 2000 physicists from the word-wide community of high-energy physicists. These developments provide clear evidence of the ongoing widespread support for the near-term construction of a linear collider.

Technology: In February 2001 ICFA requested the International Linear Collider Technical Review Committee (ILC-TRC) to assess the current technical status of electron-positron linear collider designs in the various regions. The ILC-TRC concluded that, based on the progress in both major technologies, a linear collider could be built in the next few years. As a consequence ICFA established a process to select one technology, in order to focus the world-wide efforts, and in fall of 2003 set up an International Technology Recommendation Panel which was charged to provide its recommendation before the end of 2004.

Organisation: In 2002 ICFA set up an International Linear Collider Steering Group (ILCSC) which is charged to engage in explaining the intrinsic scientific and technological importance of the project; to engage in defining the scientific roadmap, the scope and primary parameters for machine and detector; to monitor the machine R&D activities and make recommendations on the coordination and sharing of R&D tasks as appropriate; and to identify models of the organizational structure, based on international partnerships, adequate for constructing the LC facility. The ILCSC is supported by steering groups in the three regions, each with a mandate strongly allied with the ILCSC.

At present the ILCSC is preparing a recommendation on how best to establish an international design group that can start the machine design as soon after the technology decision as is possible.

ICFA reaffirms its conviction that the highest priority for a new machine for particle physics is a linear electron-positron collider with an initial energy of 500 GeV, extendible up to about 1 TeV, with a significant period of concurrent running with the LHC.


The January 2004 OECD Ministerial Statement on International Co-operation on Large Accelerator-based Projects in High-Energy Physics

Ministers expressed their appreciation for the work of the OECD Global Science Forum Consultative Group on High-Energy Physics. They welcomed the report from the Group and commended the clarity and world-wide consensus they found amongst the high-energy physics community in developing the Roadmap for future large accelerator-based facilities.

In particular, the Ministers note several important points that were articulated in the report:

  • A roadmap that identifies four interdependent priorities for global high energy physics (HEP)facilities

    i) the exploitation of current frontier facilities until contribution of these machines is surpassed,

    ii) completion and full exploitation of the Large Hadron Collider at CERN,

    iii) preparing for the development of a next-generation electron-positron collider, and

    iv) the continued support for appropriate R&D into novel accelerator designs.

  • The need to have large, next-generation facilities funded, designed, built, and operated as global scale collaborations with contribution from all countries that wish to participate.
  • The need for strong international R&D collaboration and studies of the organisational, legal, financial, and administrative issues required to realize the next major accelerator facility on the Consultative Group’s Roadmap, a next generation electron-positron collider with a significant period of concurrent running with the LHC.
  • The need to continue to educate, attract and train young people in the fields of high-energy physics, astrophysics and cosmology in the face of the increasingly competitive environment where all areas of science, industry and commerce are seeking to capture the imagination of the most creative minds.

Ministers agreed that, given the complexity and long lead times for decision making of major international projects, it is important that consultations continue within the scientific communities and, when it becomes appropriate, within interested governmental communities in order to maximise the advantages offered by global collaboration.