upsilon meson

{{Infobox particle

| name = Upsilon ({{SubatomicParticle|Upsilon}})

| image = 150px

| caption = 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.

| num_types = 1

| composition = {{SubatomicParticle|Bottom quark}}{{SubatomicParticle|Bottom antiquark}}

| statistics = Bosonic

| group = Mesons

| interaction = Strong, weak, electromagnetic, gravity

| antiparticle = Self

| status =

| theorized =

| discovered = E288 experiment (1977)

| symbol = {{SubatomicParticle|Upsilon}}

| mass = {{val|9.46030|(26)|u=GeV/c2}}

| mean_lifetime = {{val|1.21|e=-20|ul=s}}

| decay_particle =

| electric_charge = 0 e

| spin = 1

| strangeness =

| charm =

| bottomness =

| topness =

| isospin = 0

| hypercharge = 0

| parity = -1

| c_parity = -1

}}

The Upsilon meson ({{SubatomicParticle|Upsilon}}) 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 {{val|1.21|e=-20|ul=s}} and a mass about {{val|9.46|ul=GeV/c2}} in the ground state.

File:Quark structure bottomonium.svg|Quark structure of the Upsilon meson

See also

  • Oops-Leon, an erroneously-claimed discovery of a similar particle at a lower mass in 1976.
  • 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

  • {{cite journal

| author=D.C. Hom| year=1977

| url=https://lss.fnal.gov/archive/1977/pub/Pub-77-058-E.pdf

| title=Observation of a Dimuon Resonance at 9.5 Gev in 400-GeV Proton-Nucleus Collisions

| journal=Physical Review Letters

| volume=39 | issue=5

| pages=252–255

| doi=10.1103/PhysRevLett.39.252

| bibcode=1977PhRvL..39..252H

|display-authors=etal}}

  • {{cite journal

|author1-link=John Yoh

| author=J. Yoh

| year=1998

| url=https://lss.fnal.gov/archive/1997/conf/Conf-97-432-E.pdf

| title=The Discovery of the b Quark at Fermilab in 1977: The Experiment Coordinator's Story

| journal=AIP Conference Proceedings

| volume=424 |pages=29–42

| doi=10.1063/1.55114

| bibcode=1998AIPC..424...29Y

}}

  • {{cite journal

| author=S. Eidelman et al. (Particle Data Group)

| year=2004

| journal=Physics Letters B

| volume=592 | pages=1

| title=Review of Particle Physics – {{SubatomicParticle|Upsilon}} meson

| issue=1–4

| url=https://pdg.lbl.gov/2005/listings/m049.pdf

| doi=10.1016/j.physletb.2004.06.001

|arxiv = astro-ph/0406663 |bibcode = 2004PhLB..592....1P }}

{{Particles}}

{{Authority control}}

{{DEFAULTSORT:Upsilon Meson}}

Category:Mesons

Category:Onia

Category:Subatomic particles with spin 1

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