The
Upsilon meson is a
quarkonium state (i.e.
flavourless 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 and a mass about in the ground state.