The Y particle

Subatomic particle

In physics or chemistry, subatomic particles are the smaller particles composing nucleons and atoms. There are two types of subatomic particles: elementary particles, which are not made of other particles, and composite particles...

 is a previously unpredicted particle observed 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...

 and announced on 17 March 2009. This particle is extremely rare and was detected in only 20 of billions of collisions.

Since it decays into J/ψ and φ

Phi meson

In particle physics, the phi meson is a vector meson formed of a strange quark and a strange antiquark. It has a mass of .-Overview:-See also:*Charmonium*List of mesons*List of particles*Quark model...

 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...

s, it has been suggested that this particle is composed of 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 and charm antiquarks, possibly even a four quark combination

Tetraquark

In particle physics a tetraquark is a hypothetical meson composed of four valence quarks. In principle, a tetraquark state may be allowed in quantum chromodynamics, the modern theory of strong interactions. However, there has been no confirmed report of a tetraquark state to date...

.
The existence of the particle has not been confirmed by any other experiment. The Belle experiment has searched for
this particle but found no evidence for its existence

The Particle Data Group

Particle Data Group

The Particle Data Group is an international collaboration of particle physicists that compiles and reanalyzes published results related to the properties of particles and fundamental interactions. It also publishes reviews of theoretical results that are phenomenologically relevant, including...

has renamed this particle, to follows its naming conventions to the X(4140).

External links

• Press release kit for the Y(4140). Contains images of decay modes and resonance data.