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June 24, 2002
Physicists gather at UC Santa Cruz to plan new linear collider project
Public invited to attend lecture on the science of particle physics
By Tim Stephens
UCSC will host an international gathering of particle physicists this week to discuss
the development of a next-generation international particle accelerator facility.
The Santa Cruz Linear Collider Retreat, June 26 to 29, will begin with a public presentation
on the science of particle physics on Wednesday evening.
There will be two public lectures on Wednesday, June 26, starting at 7 p.m. in
Theater Arts Building M, Room 110. Helen Quinn, a theoretical physicist at the Stanford
Linear Accelerator Center (SLAC), will speak on "The Science of Particle Physics."
Rick Van Kooten, a physicist at Indiana University, will speak on "The Next
Mega Machine: The Linear Collider." The talks are free and open to the general
public.
The UCSC meeting is one of a series of meetings of the American Linear Collider Physics
Group, which is developing plans for a next-generation linear collider facility,
currently referred to simply as the Linear Collider.
Physicists use powerful accelerators and colliders to study the fundamental particles
of matter and the forces between them. The new Linear Collider is being designed
to extend the study of particle physics beyond the capacity of current machines.
The Santa Cruz Institute for Particle Physics (SCIPP) at UCSC is already involved
in research and development of detector technology for the Linear Collider, said
Bruce Schumm, associate professor of physics. Schumm, who is organizing the Santa
Cruz meeting, leads one of the project's working groups.
The current prevailing theory of particle physics, called the Standard Model, is
based on decades of research at accelerator facilities. It has held up well despite
repeated challenges, but precision measurements at currently available energies can
only be understood by postulating new phenomena at energies that will be accessible
at the next generation of particle colliders. Research at these higher energies will
provide new insights about the nature of matter and the forces that shape the universe,
and may possibly alter our notions of space and time, Schumm said.
To develop the Linear Collider, U.S. particle physics labs are working cooperatively
with the Deutsches Elektronen-Synchrotron (DESY) in Hamburg, Germany, and the High
Energy Accelerator Research Organization (KEK) in Tsukuba, Japan. Two possible U.S.
sites for the Linear Collider have been identified--FermiLab, near Chicago, and a
site near Davis, California. DESY is a possible European site, and Japanese scientists
are expected to describe potential sites in Japan at the Santa Cruz meeting.
The Linear Collider project would take many years to complete, and the facility would
not begin operation until sometime after 2010, Schumm said. Before then, physicists
will begin using the Large Hadron Collider (LHC), currently under construction at
the European Organization for Nuclear Research (CERN) in Geneva, Switzerland. The
LHC is a proton-proton collider, producing collisions between protons at higher energies
than currently possible.
The Linear Collider will be an electron-positron collider. Unlike protons, which
are composed of smaller particles called quarks and gluons, electrons and positrons
are indivisible particles. This means that the results from the Linear Collider will
be easier to interpret than those from the LHC. The two facilities will give particle
physicists complementary information, Schumm said.
The Higgs boson, a theoretical particle that may explain how fundamental particles
acquire mass, will be a primary focus of attention at both LHC and the Linear Collider.
"The LHC will almost certainly detect the Higgs boson if it exists, but the
Linear Collider will enable us to make precise measurements of the properties of
the Higgs particle to determine whether it behaves as predicted and to see if it
does in fact solve the problems that it is predicted to solve," Schumm said.
About 150 physicists are expected to attend the Santa Cruz meeting, including the
directors of several national and international physics laboratories, as well as
representatives from the U.S. Department of Energy and the National Science Foundation.
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