With the termination of the SSC, the CERN LHC physics program represents the most favorable, and perhaps only possibility to address the physics issues outlined above. Indeed, for the last decade, the SSC had represented, by consensus of the community, the top priority of the US HEP program. The physics issues are the same at LHC, although their exploration is made more difficult by the higher luminosity required to compensate for the lower center-of-mass energy at the LHC.
In addition to physics issues, collaboration on the LHC by US groups represents the first step towards ``global'' collaboration in HEP projects. Surely, advances in HEP are costly endeavors, and should properly be addressed in the context of global collaborations.
This document summarizes the involvement of US HEP groups in one of the two LHC detectors, the Compact Muon Solenoid (CMS). On the basis of their interest in the compelling physics opportunities available at CMS, many US groups have decided to join. It is of critical importance that these groups be accorded financial support in FY95 and FY96. Given the schedule for freezing the design of CMS, the US community must receive R&Dfunding in these fiscal years if it is to make an intellectual contribution to the CMS design. The present due date for the CMS design report to the CERN Council is December 15, 1994.
The CMS management has expressed serious willingness to welcome a
substantial number () of US
physicists as full partners. The new collaborators would bring
intellectual and technical contributions from their work on the SSC
experiments, SDC and GEM. It must be emphasized that this new
collaboration is the most direct method possible to realize the SSC
investment in HEP. In addition, the LHC project could be placed on a
more timely and secure framework, and ``staging'' of the detector
could be avoided with the added financial contributions of new
collaborators from the US. These contributions would lead to a
schedule limited more by technical rather than financial constraints,
and thus advance the science of HEP. A list of US groups having
expressed interest in joining CMS is given in Table 1. That list
contains 32 universities and 4 National Laboratories. The number of
signatories of this Letter of Intent is 252.