Particle physics. A woman physicist studies event displays from the D-Zero detector at Fermilab, the Fermi National Accelerator Laboratory near Chicago, USA. The D-Zero detector records the collisions of protons and antiprotons accelerated to high energy in Fermilab's accelerators. The images on the computer screens are the result of proton-antiproton collisions. The circular structure on each monitor represents the end view of the cylindrical detector. The tracks, lines and blocks on the computer screen represent the paths and energies of particles created in the collisions. D-Zero co-discovered the top quark in 1995.