Upsilon particle

Muons can easily penetrate many meters of iron and can sometimes cause problems in particle physics research. For example, the upsilon experiment at Fermilab in 1977, conducted by L M. Uederman and olhers, required building a simple magnetic system that would remeasure each muon s energy after it emerged from the main detector. See also Upsilon Particle and Particles (Subatomic). 

UPSILON PARTICLE. As of 1977, when the upsilon particle was discovered at the Fermi National Accelerator Laboratory, the particle was die heaviest to be identified. Discovery of upsilon prompted physicists to introduce a massive new quark, raising the number of quarks from four to five (but probably six). The upsilon has a mass three times greater dian any subatomic entity previously detected. It was discovered in energetic collisions between protons and copper nuclei. With a mass at its lower energy state equivalent to 9.0 GeV and masses in excited states equivalent to 10 and 10.4 GeV, the upsilon particle has been interpreted... 

An electronic display of the decay of an upsilon particle in a CLEO detector. 

The discovery of the J/. was soon followed by the unveiling of a whole family of new particles which gave a totally unexpected comrse to particle physics. A few days after the discovery of the J/ a second, heavier particle, a recurrence of the J/ , was found at SPEAR. Optimistically labelled it has a mass of 3686 MeV/and full width of 278 32 keV. Needless to say, several other members of the J/ family have since been found. In 1977, the first member of a new generation of narrow resonances was found, the upsilon T, with a mass of 9.46 GeV/c and a full width of 52.1 2.1 keV. It was discovered at Fermilab (Herb et al., 1977) by looking at n pairs in the reaction... 

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