AIP FYI #113 Marburger on Science, Society, and Accelerators

John Marburger, Director of the Office of Science and Technology
Policy, spoke at the Fortieth Anniversary Celebration of the
Stanford Linear Accelerator Center (SLAC) last week. “What can
the science community do to increase the inclination of society
to support these big machines?,” he asked. Selections from this
engaging address follow; the entire text of which may be read at
http://www.ostp.gov/html/02_10_9.html

“Who ever would have guessed when SLAC began forty years ago that
understanding the vacuum, basically empty space in our frozen
epoch of cosmic evolution, would be the most challenging problem
in physics today? The discovery in 1998, totally unexpected,
that the expansion of the universe is accelerating, is both
embarrassing and exciting. How could we have missed something
that big? There is nothing in our current theories that even
comes close to producing the right order of magnitude for the
term in Einstein’s equation, the cosmological constant, required
for this effect. What the theory gives is a joke, more than a
hundred orders of magnitude off the mark.

“The vacuum plays an essential role in the inflation theories, to
which Stanford scientists have contributed many of the most
important ideas. And once again these theories are important
because they lead to phenomena that must be understood to relate
observable features of the universe to the structure and
symmetries of microscopic models ñ models that may include
strings, and that we hope will unify gravity with the gauge
forces of the Standard Model. We are going to need all the help
we can get to tie these future theories down to empirical
reality.

“The argument for building an accelerator beyond the LHC, it
seems to me, must be strongly linked to these ideas. At some
point we will simply have to stop building accelerators. I don’t
know when that point will be reached, but we must start thinking
about what fundamental physics will be like when it happens.
Theory, of course, will continue to run on. But experimental
physics at the frontier will no longer be able to produce direct
excitations of increasingly massive parts of nature’s spectrum,
so it will have to do something else. There are two
alternatives. The first is to use the existing accelerators to
measure parameters of the standard model with ever-increasing
accuracy so as to capture the indirect effects of higher energy
features of the theory, much as BaBar is doing today at this
laboratory. The second is to turn to the laboratory of the
cosmos, as physics did in the cosmic ray era before accelerators
became available more than fifty years ago.

“Are we ready for this? When the last accelerator is built, will
there still be a gap in our knowledge that will prevent us from
working productively in the ‘Laboratory of the Cosmos?’ There is
no question that our ability to interpret what we see in the sky
depends on what we have learned about fundamental matter in our
earthly laboratories. How strong is this dependence? How much
more do we need from earth-bound accelerators before we can do
without them? How can we best prepare for the end of the
accelerator era in fundamental physics?

“However, and whenever, this transition occurs, it is clear to me
that the fates of deep space astronomy and particle physics are
strongly entwined. In the long run, the future of particle
physics lies in space-based experiments, and its productivity
will depend on having a model of nature that is complete enough
to exploit cosmic phenomena as a guide to theory. Now is the
time to begin preparing for the long run.

“I mentioned the ‘ragged edge’ of society’s ability to deliver
big accelerators. ‘Society’ likes science. It is willing to tax
itself to provide funds for basic, discovery-oriented research.
It reads popular science books, watches educational television
shows on science, and encourages its young people to study such
impractical science topics as dinosaurs and black holes. In
Congress, science enjoys bipartisan support. All postwar
administrations have supported basic research, including the
administration of President George W. Bush. But there is a
limit. Not, unfortunately, a well-defined or clearly articulated
limit. We saw this in the saga of the Superconducting Super
Collider. That project did not fail because of lack of love for
particle physics, or even for lack of understanding of the
importance of the Higgs mechanism. It failed, in my opinion,
because the scale of the project exceeded a critical size ñ a
size well within the ability of society to pay, but placed within
a domain of society’s parameter space that is unstable against
chaotic behavior.

“If the SSC was beyond a threshold of stability, and the LHC is
beneath it, the Next Linear Collider [NLC] is already in a gray
area. I have expressed elsewhere my conviction, in agreement
with the High Energy Physics Advisory Panel, that the NLC is a
logical choice for a next big accelerator after LHC. I was
always taken with the simplicity of lepton-antilepton collisions,
which create ‘little big bangs’ with simple spatial structure and
simple quantum numbers. Moreover, I think a lepton collider is
the right kind of machine to do precision experiments of the sort
that are going to be necessary to probe mass regimes that are out
of reach. Whether it will be the ‘last big accelerator,’ or
whether a muon collider or something else will have that honor, I
don’t know. Perhaps we will find a way to keep building ever
larger accelerators throughout the 21st century. But already
with the NLC we are going to have to change the way such devices
are financed. No single nation is likely to pick up as much of
the cost of the NLC as host countries have in the past. To be
successful, the project will need a new model of international
support.

“What can the science community do to increase the inclination of
society to support these big machines? I think the best approach
— and this is after a year in Washington, D.C. — is to tell the
truth, the whole truth. But it must be told carefully, in
language that society can understand.

“The truth is that particle physics is as exciting as it ever
was. It is not dead. The fact that we are having trouble seeing
beyond the Standard Model is not bad news. It means that the
next discoveries will have a disproportionate impact on our
understanding of Nature. For the first time in a quarter-century
experiment is driving theory at the frontier, and not the other
way around.

“The truth is that Nature functions in such a way as to bring
together the science of the very large with the science of the
very small, and that opportunities have emerged for discovery
about the fundamental nature of the universe that we never
expected. Technology places these discoveries within our reach,
but we need to focus efforts across widely separated disciplines
to realize the new opportunities.

“The truth is that exploration of the new frontier will attract
the best young minds who will produce new technology to overcome
the barriers which define the limits of our perception. The
excitement of discovery, and the human will to see farther are
powerful sources of vitality in our society.

“What we should not do is give the impression that the
accelerators and other large scale apparatus are ends in
themselves. Only the search for the ultimate shape of Nature can
justify such large expenditures, and we must subordinate all
other considerations to that grand end. Nor should we
over-emphasize the practical impact of new technologies that
will emerge from the search. Too few of us are truly aware of
the actual histories of previous impacts. To those who know, the
proposition that high energy physics was responsible for magnetic
resonance imaging devices, for example, is naive. And above all
we should never assume that the lay public will not be able to
appreciate what we are about. We need to support the science
journalists who care, and those among us who have the knack of
translating the fragmented and highly technical knowledge that is
accumulating so rapidly into a coherent story as appealing to the
lay public as it is to us.”

Richard M. Jones

Media and Government Relations Division

The American Institute of Physics

fyi@aip.org

(301) 209-3095

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