<IMG SRC="navi.gif" WIDTH=160 HEIGHT=440 usemap="#navi" BORDER=0> Particle Decays and Annihilations     Electron/Positron Annihilation

When an electron and positron (antielectron) collide at high energy, they can annihilate to produce charm quarks which then produce D+ and D- mesons.

<< Slower

Faster >>

  • Frame 1: The electron and positron zoom towards their certain doom.
  • Frame 2: They collide and annihilate, releasing tremendous amounts of energy.
  • Frame 3: The electron and positron have annihilated into a photon, or a Z particle, both of which may be virtual force carrier particles.
  • Frame 4: A charm quark and a charm antiquark emerge from the virtual force carrier particle.
  • Frame 5: They begin moving apart, stretching the color force field (gluon field) between them.
  • Frame 6: The quarks move apart, further spreading their force field.
  • Frame 7: The energy in the force field increases with the separation between the quarks. When there is sufficient energy in the force field, the energy is converted into a quark and an anti-quark (remember ).
  • Frames 8-10: The quarks separate into distinct, color-neutral particles: the D+ (a charm and anti-down quark) and D- (an anti-charm and down quark) mesons.

The intermediate stages of this process occur in about a billionth of a billionth of a billionth of a second, and are not observable.