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Click on links below images for medium and high-resolution jpeg images. When using these images, please credit Fermilab. Six quarks--up, down, strange, charm, bottom and top--are the building blocks of matter. Protons and neutrons are made of up and down quarks, held together by the strong nuclear force. The DZero experiment has discovered the Cascade-b particle, which contains a down quark (d), strange quark (s) and bottom quark (b). It is the first particle ever observed with one quark from each generation of particles. 
The Cascade-b particle (Ξb) is short-lived. Once produced, it travels only several millimeters before the action of the weak nuclear force causes it to disintegrate into two well-known particles called J/Ψ and Ξ-. The J/Ψ then promptly decays into a pair of muons, common particles that are cousins of electrons. The Ξ- baryon, on the other hand, travels several centimeters before decaying into yet another unstable particle called a Λ baryon, along with another long-lived particle called a pion. The Λ baryon too can travel several centimeters before ultimately decaying to a proton and a pion. The Fermilab accelerator complex accelerates protons and antiprotons close to the speed of light. Converting energy into mass, the Tevatron collider can produce particles that are heavier than the protons and antiprotons that are colliding. The Tevatron produces millions of proton-antiproton collisions per second, maximizing the chance for discovery. Two experiments, CDF and DZero, search for new types of particles emerging from the collisions. The DZero detector is about the size of a 3-story house. The detector surrounds the collision point and records the path, energy and charge of short-lived particles emerging from the collisions. Its subsystems record the "debris" emerging from high-energy proton-antiproton collisions, unveiling the forces governing the subatomic world. Tracing the particle tracks back to the center of the collision, scientists discover what processes take place at the core of proton-antiproton collisions. Some of the 700 scientists of the DZero collaboration in front of the DZero detector shortly before it began taking data in 2001. Return to Press Release |
