Discovery of The Top Quark
One of CDF's most famous observations is the observation of the top quark in February 1995. The existence of the top quark was hypothesized after the observation of the Upsilon in 1977, which was found to consist of a bottom quark and an anti-bottom quark. The Standard Model, which today is the most widely accepted theory describing the particles and interactions, predicted the existence of three generations of quarks. The first generation quarks are the up and down quarks, second generation quarks are strange and charm, and third generation are top and bottom. The existence of the bottom quark solidified physicists’ conviction that the top quark existed. The top quark was the very last quark to be observed, mostly due to its comparatively high mass. Whereas, the masses of the other quarks range from .005 GeV (up quark) to 4.7GeV (bottom quark), the top quark has a mass of 175 GeV. Only Fermilab’s Tevatron had the energy capability to produce and detect top anti-top pairs. The large mass of the top quark caused the top quark to decay almost instantaneously, within the order of 10−25 seconds, making it extremely difficult to observe. The Standard Model predicts that the top quark may decay leptonically into a bottom quark and a W boson. This W boson may then decay into a lepton and neutrino (t→Wb→ѵlb). Therefore, CDF worked to reconstruct top events, looking specifically for evidence of bottom quarks, W bosons neutrinos. Finally in February 1995, CDF had enough evidence to say that they had "discovered" the top quark.
Read more about this topic: Collider Detector At Fermilab
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