44 | New Scientist | 23 November 2019
interaction that would be accessible to the
LHC or to a future collider. Colliders are one
tool that we have to explore dark matter, but
not the only one.Is fundamental physics in a bit of a funk, trying
to think too much about established theories
concerning things like dark matter and not
about new ideas?
I think you are correct. We have to approach
our explorations with a very open mind. That’s
why the LHC experiments, in particular the
two general-purpose experiments, ATLAS and
CMS, have been built in a way that, in principle,
allows them to detect any type of new particles,
whether from an established theoretical
scenario like supersymmetry or extra
dimensions, or something new. It’s very
important to be very broad and very open.Earlier this year, CERN published plans for the
Future Circular Collider, a larger version of the
LHC. What convinces you that this is the way
forward for particle physics?
First of all, CERN is doing design studies and
R&D for two projects. One is a linear collider
up to 50 kilometres long called CLIC, which
will smash electrons against positrons coming
from the opposite direction. It will allow
detailed studies of the Higgs boson and
provide sensitivity to new physics up to very
high energy scales. The other is the Future
Circular Collider, which is a ring like the Large
Hadron Collider but three times bigger.
However, they are not just bigger, they
also come with much more sophisticated
and powerful technologies that will allow
us to make a big step up in the energy and
intensity of the particle beams compared
with previous colliders.What is the benefit of that?
A Future Circular Collider can collide electron-
positron beams and proton-proton beams in
more than one experiment. An electron-
positron collider would allow detailed studies
of not just the Higgs boson, but other known
particles. A proton-proton collider would
allow the production and observation of
heavy, new particles.Some theoretical models suggest that there
aren’t any more particles at the energy scales we
can realistically reach with a collider. Wouldn’t it
be a big gamble to build these things?
What is the goal of particle physics, and in
particular of colliders? Is it to discover new
particles, or to make a step forward in our
understanding of fundamental physics?The LEP [Large Electron-Positron] Collider,
which was the predecessor of the Large
Hadron Collider, didn’t discover a single
particle, and yet there are few projects in
the history of particle physics that have
progressed our understanding of
fundamental interactions so much.
The goal of any scientific exploration is
to make progress in our understanding of
nature. Discovering a new particle is one way,
but very precise measurement of known
particles is as important, as is ruling out
ideas that are unfounded.What would you say to people who say it isn’t
worth spending that amount of money on
particle physics, that it should go on something
like mitigating climate change?
Obviously, we should also be spending money
on mitigating climate change. But one doesn’t
exclude the other. I think it is the duty and the
right of humanity to understand how nature
works, how the universe evolved, and how it
will evolve in the future. Pushing back the
limits of knowledge is one of our aspirations
and obligations.
Apart from that, science in general, and
particle physics in particular, is a driver of
innovation, because our goals are often so
ambitious that they require the development
of new technologies. From CERN alone, the
spin-offs are huge: the World Wide Web,
medical applications and many others.
And there is also another important role
of science nowadays: to foster collaboration
across borders and all over the world. In a
fractured world with many forces pulling it
apart rather than together, science is still an
example of what humanity can do when we
use our cultural diversity to work together
and do something good.Can that sort of ideal prosper in this fractious
period in international relations?
I think science carries a good message of peace
and of collaboration at a very delicate time.
Perhaps even more than the arts, it brings
together people from all over the world,
because it is based on facts, and not on
opinions. The laws of nature are the same
here as in the UK, in the US, in China, so
nobody can argue about them.
Science is a very strong glue that unites
people of all cultures, traditions, passports,
religions and political beliefs. We have
scientists sitting around tables here at CERN
whose countries will not sit around the table
for political discussions. That is a very
important message.“ The laws of
nature are the
same here as in
the US or China,
so nobody can
argue about
them”
Fabiola Gianotti opens Esplanade des
Particules, a new plaza outside CERNCE
RN