Glossary of Physical Terms used in the Poems

The Quark Sisters: Quarks are thought to be the most elementary of particles - many other particles are made from combinations of them e.g. the proton and the neutron have three quarks each, and more exotic particles such as pions have two quarks. Particles made from quarks are called hadrons. The theory that gave rise to quarks was worked out in the 1960's which probably explains their names. Quarks come in three 'colours' - red, blue and green. The colours have nothing to do with real colour and are merely used to label the quarks. In addition each quark has a 'flavour': up, charm and top (which have an electric charge of 2/3 that of a proton); and down, strange and bottom (each with a charge of -1/3 that of a proton). In order to break apart particles such as the proton into its constituent quarks, enormous energies are required such as that provided at the particle accelerator facility at CERN in Geneva. Very recent experiments there have given us the first experimental evidence of individual, isolated quarks.