**U.S. Participation in the Large Hadron Collider at CERN**

**An Investment to Maintain U.S. Scientific Leadership**

Through the U.S. Department of Energy and the National Science
Foundation, the United States will invest \$531 million over the next
eight years in a new particle accelerator, the Large Hadron Collider, to
be built in Geneva, Switzerland. The U.S. is one of several
non-CERN-member nations, including Japan, Canada and Russia,
contributing to the LHC. Why does this investment make sense for the
United States?

***The U.S. is a world leader in High Energy Physics.***

Today and for the next several years, the Tevatron, the world\'s
highest-energy particle accelerator, at the Department of Energy\'s
Fermi National Accelerator Laboratory, represents the energy frontier
for research and discovery in particle physics, the science of the
fundamental nature of matter. The nation\'s investment in the Tevatron
provides unsurpassed opportunities for discoveries now and in the
opening years of the new millennium. But when the LHC begins operating
sometime after 2005, the U.S. will no longer have the highest-energy
particle accelerator. The LHC provides a cost-effective opportunity for
U.S. scientists to continue to work at the energy frontier---and to
develop the technologies for building the accelerators that will someday
follow the LHC.

***After 2005, the energy frontier will move to the Large Hadron
Collider.***

The LHC is a new particle accelerator, 16 miles in circumference, to be
built at CERN, the European Laboratory for Particle Physics, near
Geneva, Switzerland. It will reach the highest energy yet achieved by
any particle accelerator---about seven times the energy of Fermilab\'s
Tevatron. Physicists will use the LHC for the next generation of
experiments to explore the fundamental nature of matter.

***U.S. Involvement in LHC***

> • When the energy frontier moves from Fermilab\'s Tevatron to the LHC
> after 2005, about 25 percent of U.S. experimental particle physicists
> will participate in physics experiments at the LHC.
>
> • U.S. physicists from six national laboratories and 60-plus
> universities will collaborate in developing and constructing the LHC
> accelerator and its two major detectors, ATLAS and CMS..

***Accelerator Construction***

• The U.S. will participate in LHC accelerator construction at a cost of
\$200M over nine years, about five percent of total accelerator
construction costs.

• Of the \$200M in U.S. accelerator funding, about \$90M will be spent
domestically for goods from U.S. industry.

• The remaining \$110 M will pay for design and fabrication in the U.S.
of advanced accelerator systems by a collaboration of three U.S.
national labs: Fermilab, Brookhaven, and Berkeley Lab.

• Worldwide collaboration in accelerator construction allows the machine
and the science to benefit from the use of the best talents from all
regions of the world.

***Detector Design and Construction***

> • The U.S. will participate in design and construction of two large
> LHC experiments, CMS and ATLAS, at a cost of \$331M over eight years,
> about 20 percent of the total construction cost of these experiments.
> \$250M will come from DOE and \$81M from NSF.

• These funds will be used to support researchers at U.S. universities
and national laboratories to design and build state-of-the-art detector
systems.

• More than 500 scientists from over 60 U.S. universities and six
national laboratories have joined the U.S. CMS and ATLAS collaborations.
Fermilab is the host laboratory for the U.S. CMS effort; Brookhaven
National Laboratory is the host laboratory for the U.S. ATLAS
activities.

**U.S. Collaboration in the LHC**

**Returns on the Investment**

Collaboration in the LHC project makes sense for the U.S. because of the
quality of the science, the technical strength of the project, and the
terms of the agreement.

> ***Scientific quality***
>
> • The science at the LHC is compelling; it represents the next
> generation of discovery in the search to understand the fundamental
> nature of matter. Participating in the LHC will help the U.S. remain
> among world leaders in the science of high-energy physics.
>
> • Collaboration in the LHC will advance U.S. capability in forefront
> technologies, such as superconducting magnet design, that are critical
> not only for the LHC but for the U.S. accelerators of the future.
>
> • U.S. participation in the LHC has been strongly endorsed by the
> Division of Particles and Fields of the American Physical Society, the
> High Energy Physics Advisory Panel to DOE, the special NSF panel on
> Elementary Particle Physics, and the National Science Board.

***Technical strength***

• Participation in the LHC project will strengthen the domestic research
program by keeping U.S. universities and national laboratories involved
in cutting-edge research. The design studies, development of detector
and accelerator systems, and the research at the LHC will advance the
skills of U.S. physicists and engineers and enhance the infrastructure
within the U.S. labs.

• CERN is a strong and reliable partner. Like the U.S., CERN is also a
world leader in high-energy physics. CERN has an excellent 40-year
record of accelerator and detector construction, including the
accelerator that now occupies the tunnel that will house the LHC.

> • About 25 percent of American experimental high energy physicists
> plan to do research at the LHC. Twenty percent of the physicists who
> are working on constructing the two large experiments are U.S.
> scientists.
>
> ***Terms of the agreement***

• The LHC will be a highly cost-effective way for the U.S. to continue
to do forefront high-energy physics research. The cost to the U.S. will
be about 10 percent of the total LHC accelerator-plus-experiment cost,
whereas U.S. researchers will make up about 20 percent of the users of
the two major detectors.

• Of the proposed \$450M U.S. contribution to CERN by the Department of
Energy and \$81M from NSF, almost all will be spent domestically on the
purchase of goods and services from U.S. industry and for U.S. wages and
salaries.

*Nov 13, 2023*