The goal of accelerator-based experiments is to understand how nature
works at the smallest distances and largest energies possible. In
particular, we ask the questions “What are the smallest building
blocks of the universe?” and “What are the forces by which they
interact?” Our current answers are codified in the table below which
lists 12 fundamental building blocks (the quarks and leptons) and 4
force carriers (the bosons) for the Weak force, the Electromagnetic
force and the Strong force. Gravity has a negligible impact here, but
is still missing from this theory
The theory (or mathematical model) which best describes the particles
in the table and their interactions is called the standard model. The
standard model was initially proposed in the 60’s and early 70’s, and
over the past 35 years a series of experiments at SLAC, BNL, Fermilab,
KEK and CERN have shown that the standard model describes all
However, we have not yet found everything the standard model predicts.
In particular, the standard model requires the existence of a new
particle, the Higgs Boson, needed to explain how the W and Z boson
have non-zero masses. The Higgs boson has not been found yet and
searching for evidence of its existance (or conclusive evidence of its
non-existence) is a major part of what we do.
Einstein’s famous equation E = mc2, shows that high energy (E)
corresponds to high mass (m), so with high energy accelerators we can
look for particles with large mass. The heaviest fundamental particle
observed so far, the top quark, has a mass of 172 GeV, which is slightly
less than a single atom of gold. The cartoon to the right shows the
conversion of energetic quarks with little mass into massive top quarks
and the subsequent decay of the top quarks.
In addition to studying the
known particles looking for discrepancies with standard model
predictions and looking for the Higgs boson, a significant part of our
research involves looking for new particles predicted by theories
(whimsically illustrated to the right) which address possible shortcomings of
the standard model.
High energy also corresponds to short distances. Regular optical microscopes
can measure distances as small as 0.5 mm, or 109 times larger than a proton.
With the accelerators we use for research, we study distances as short as 10-10
nm, 10,000 times smaller than the diameter of a proton.
standard model has one known shortcoming - it does not incorporate neutrino
mixing (and therefore neutrino masses).
Opinions expressed through this page are those of the hadron collider
experiments group, and do not reflect those of the State University or the
State of New York.