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# Upsilon particle

Composition: Upsilon ($\Upsilon\,$) A plot of the invariant mass of muon pairs, from the Upsilon particle discovery paper. The peak at about 9.5 GeV represents the particle itself. Composite:Quarks: 1 bottom, 1 antibottom Hadron Meson 0 C 1

The Upsilon particle ($\Upsilon\,$) is a flavorless meson formed from a bottom quark and its antiparticle. It was discovered by the E288 collaboration, headed by Leon Lederman, at Fermilab in 1977, and was the first particle containing a bottom quark to be discovered because it is the lightest that can be produced without additional massive particles. It has a lifetime of 1.21x10-20 seconds and a mass about 10 GeV.