Top quark event. Electronic display of a top quark event in the D-Zero detector at Fermilab, the Fermi National Accelerator Laboratory near Chicago, USA. The image shows the result of a proton-antiproton collision. A top quark and an anti-top quark are produced which decay into two muons (blue tracks), four jets of other particles (red & white blocks) and a neutrino (pink block). The neutrino leaves no trace in the detector, but carries away energy. The pink block shows how much energy is missing and where it went. The top quark was discovered by the CDF and D-Zero detectors at Fermilab in 1995.