Top quark event. Electronic display of a top quark event in the CDF (Collider Detector Facility) 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 4 jets of particles (red & yellow blocks) and a neutrino. 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 CDF detector (commissioned in 1985) discovered the top quark in 1995.