Redefining Reality - The Intellectual Implications of Modern Science

epulsion. Nuclei should blow themselves apart because of
the electrostatic force between protons. The only forces we
knew of were gravity and electromagnetism, and neither could
explain what held nuclei together.
Another problem concerns the neutron. Electrical charge
explains how the proton and electron stick together in making
a neutron, but what about the neutrino? There must be some
sort of force that acts on neutrinos, and it would have to be
different from electrical forces (because the neutrino is neutral)
and gravity (because it is so tiny).
The force that binds protons together would have to overcome
the electrostatic force and must be the stronger of the two and
active only in the nucleus because it is seen nowhere else. It
was called the . The force that exposes
itself when the neutron breaks down to emit an electron and a
neutrino is called the .
What started out as a simple picture of reality with two forces—
gravity and electromagnetism—and two basic components—
electrons and protons—had been exploded. Using particle
accelerators, physicists began to discover a wealth of new particles;
ultimately, these were categorized into what is now known as the
standard model.
According to the standard model, there are two groups of particles,
fermions and bosons. Fermions come in two classes, leptons
(elementary particles) and hadrons (made up of quarks). Leptons
include the electron, the muon, and the tau. Each lepton has an
antiparticle that is identical except for its charge. Additionally, each
lepton has an associated neutrino and antineutrino.
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