bottom(ness): property of hadrons containing bottom quarks or
antiquarks
bottom quark: most massive example of quark with electric
charge −1/3
bubble chamber: form of particle detector, now obsolete, revealing the
flightpaths of electrically charged particles by trails of bubbles
CERN: European Centre for Particle Physics, Geneva, Switzerland
charm quark: quark with electric charge +2/3; heavy version of the
up quark but lighter than the top quark
collider: particle accelerator in which beams of particles moving in
opposing directions meet head on
colour: whimsical name given to property of quarks that is the source of
the strong forces in the QCD theory
conservation: if the value of some property is unchanged throughout a
reaction, the quantity is said to be conserved
cosmic rays: high-energy particles and atomic nuclei coming from
outer space
cyclotron: early form of particle accelerator
down quark: lightest quark with electrical charge −1/3; constituent of
protons and neutrons
electromagnetic force: fundamental force that acts through forces
between electrical charges and the magnetic force
electron: lightweight electrically charged constituent of the atom
electroweak force: theory uniting the electromagnetic and weak forces
eV (electronvolt): unit of energy; the amount of energy that an electron
gains when accelerated by one volt
E = mc
2
(energy and mass units): technically the unit of MeV or GeV is
a measure of the rest energy, E = mc
2
, of a particle, but it is often
traditional to refer to this simply as mass, and to express masses in
MeV or GeV
fermion: generic name for a particle with half-integer amount of spin,
measured in units of Planck’s constant. Examples are the quarks and
leptons.
flavour: generic name for the qualities that distinguish the various
quarks (up, down, charm, strange, bottom, top) and leptons (electron,
muon, tau, neutrinos), thus flavour includes electric charge and mass
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Particle Physics