Upsilon meson

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Upsilon (
ϒ
)
Upsilon peak.jpg
A plot of the invariant mass of muon pairs, from the Upsilon particle discovery paper. The peak at about 9.5 GeV is due to the contribution of the Upsilon meson.
Composition
b

b
StatisticsBosonic
Symbol
ϒ
AntiparticleSelf
DiscoveredE288 experiment
Mass9.46030(26) GeV/c2
Electric charge0 e
Spin1

The Upsilon meson (
ϒ
) is a quarkonium state (i.e. flavourless meson) formed from a bottom quark and its antiparticle. It was discovered by the E288 experiment team, 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 1.21×10−20 s and a mass about 9.46 GeV/c2 in the ground state.

See also[edit]

References[edit]

  • D.C. Hom; et al. (1977). "Observation of a Dimuon Resonance at 9.5 Gev in 400-GeV Proton-Nucleus Collisions" (PDF). Physical Review Letters. 39: 252–255. Bibcode:1977PhRvL..39..252H. doi:10.1103/PhysRevLett.39.252.
  • J. Yoh (1998). "The Discovery of the b Quark at Fermilab in 1977: The Experiment Coordinator's Story" (PDF). AIP Conference Proceedings. 424: 29–42.
  • S. Eidelman et al. (Particle Data Group) (2004). "Review of Particle Physics –
    ϒ
    meson"
    (PDF). Physics Letters B. 592: 1. arXiv:astro-ph/0406663. Bibcode:2004PhLB..592....1P. doi:10.1016/j.physletb.2004.06.001.