One of the ultimate goals of physics is to develop one
set of equations that can explain and make predictions for
all phenomena found in nature. This was Einstein's great
dream, and it has sparked interest in the physics community
to pursue such a theory. Currently one hears of
theoretical physicists working on a "superstring"
theory, and that many feel as though a theory of
evverything might be found in the next decade. Well,
whether or not superstring theory turns out to be
the ultimate theory, we would like to point out
that the "super" in superstring comes from another
idea called "supersymmetry." We will briefly discuss
what this means, and why scientists on CDF are
interested in it.
We currently know of hundreds of particles that can
exist in nature, all of which form a sort of particle zoo.
But scientists normally like simple pictures, and from such a
large number of particles came an idea to make the picture
of nature neater. This idea led to the quark model, which has
eventually devveloped into the standard model of particle
physics. The standard model breaks down the universe into
twelve basic ingredients that form all the matter we observe
(grouped into quarks and leptons), as well as four other types of particles that create the forces and interactions betrween the matter particles (the
gauge bosons). One of the main properties that distinguishes
quarks and leptons from the gauge bosons is the value of the
spin of the particles. Leptons and quarks have spin values
that are 1/2 multiples (1/2, 3/2, ...) of a constant and
are all called fermions, whereas gauge bosons have
integer multiples (0,1, 2,...) of the same constant and are
all called bosons.
Supersymmetry is a mathematical idea that states
something about the basic ingredients of nature, the leptons,
quarks and gauge bosons. It states that each fermion should have a
sister particle that is a boson, while each boson should have a
sister particle that is a fermion. In other words, the particle
zoo should have twice as many occupants than it currently has!
Naturally, this is a major theoretical statement, and scientists
at CDF want to investigate and see if there is any evidence
for the new particles. This has led to new searches for
supersymmetric particles (SUSY particles). From the last run CDF was
involved in, no evidence for SUSY particles was found. Rather
than simply "scrapping" the theory, perhaps the SUSY particles are
too heavy to be made by the tevatron, or they are so rare that
scientists have not seen them in abundance. Time will tell if
supersymmetry is a valid theory, but for more technical reasons
many physicists believe it will be found true and will play
an inportant role in developing a "theory of everything!"
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