The Upsilon meson is a flavorless meson

Meson

In particle physics, mesons are subatomic particles composed of one quark and one antiquark, bound together by the strong interaction. Because mesons are composed of sub-particles, they have a physical size, with a radius roughly one femtometer: 10−15 m, which is about the size of a proton...

 formed from a bottom quark

Bottom quark

The bottom quark, also known as the beauty quark, is a third-generation quark with a charge of − e. Although all quarks are described in a similar way by the quantum chromodynamics, the bottom quark's large bare mass , combined with low values of the CKM matrix elements Vub and Vcb, gives it a...

 and its antiparticle

Antiparticle

Corresponding to most kinds of particles, there is an associated antiparticle with the same mass and opposite electric charge. For example, the antiparticle of the electron is the positively charged antielectron, or positron, which is produced naturally in certain types of radioactive decay.The...

. It was discovered by the E288 collaboration, headed by Leon Lederman, at Fermilab

Fermilab

Fermi National Accelerator Laboratory , located just outside Batavia, Illinois, near Chicago, is a US Department of Energy national laboratory specializing in high-energy particle physics...

 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 .

See also

• Oops-Leon
  Oops-Leon
  Oops-Leon is the name given by particle physicists to what was thought to be a new subatomic particle "discovered" at Fermilab in 1976. The E288 collaboration, a group of physicists led by Leon Lederman who worked on the E288 particle detector, announced that a particle with a mass of about 6.0...
  
  , an erroneously-claimed discovery of a similar particle at a lower mass in 1976.
• Quarkonium
  Quarkonium
  In particle physics, quarkonium designates a flavorless meson whose constituents are a quark and its own antiquark. Examples of quarkonia are the J/ψ meson and the meson...
  
  , the general name for mesons formed from a quark
  Quark
  A quark is an elementary particle and a fundamental constituent of matter. Quarks combine to form composite particles called hadrons, the most stable of which are protons and neutrons, the components of atomic nuclei. Due to a phenomenon known as color confinement, quarks are never directly...
  
   and the corresponding antiquark.
• The particle is the analogous state made from strange quark
  Strange quark
  The strange quark or s quark is the third-lightest of all quarks, a type of elementary particle. Strange quarks are found in hadrons, which are subatomic particles. Example of hadrons containing strange quarks include kaons , strange D mesons , Sigma baryons , and other strange particles...
  
  s.
• The particle is the analogous state made from charm quark
  Charm quark
  The charm quark or c quark is the third most massive of all quarks, a type of elementary particle. Charm quarks are found in hadrons, which are subatomic particles made of quarks...
  
  s.
• List of mesons