Upsilon particle

Infobox Particle
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name = Upsilon (SubatomicParticle|Upsilon)


caption = 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.
num_types =
composition = SubatomicParticle|Bottom quarkSubatomicParticle|Bottom antiquark
family = Hadron
group = Meson
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theorized =
discovered =
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mass = |1.6865 × 10⁻²⁶ kg 9.460 30(26) GeV/c²
decay_time =
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electric_charge = 0 C
color_charge =
spin = 1
num_spin_states =

The Upsilon particle (SubatomicParticle|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 1.21×10⁻²⁰ seconds and a mass about 10 GeV.

ee also

* Oops-Leon, an erroneously-claimed discovery of a similar particle at a lower mass in 1976.
* Quarkonium, the general name for mesons formed from a quark and the corresponding antiquark.
* The SubatomicParticle|link=yes|Phi meson particle is the analogous state made from strange quarks.
* The SubatomicParticle|link=yes|J/Psi particle is the analogous state made from charm quarks.
* List of mesons

References

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# [http://pdg.lbl.gov/2005/listings/m049.pdf Technical data (pdf file)] from Particle Data Group (From 2005 update of cite journal | author= S. Eidelman et al. | journal=Phys. Lett. B | year=2004 | volume=592 | pages=1 | title=Review of Particle Physics | doi=10.1016/j.physletb.2004.06.001)