| Composition |
c c |
|---|---|
| Statistics | Bosonic |
| Interactions | Strong, weak, electromagnetic force, gravity |
| Symbol | J/ψ |
| Antiparticle | Self |
| Discovered |
SLAC: Burton Richter et al. (1974) BNL: Samuel Ting et al. (1974) |
| Mass |
5.5208×10−27 kg |
| Electric charge | 0 e |
| Spin | 1 |
5.5208×10−27 kg
The
J/ψ
(J/psi) meson /ˈdʒeɪ ˈsaɪ ˈmiːzɒn/ or psion is a subatomic particle, a flavor-neutral meson consisting of a charm quark and a charm antiquark. Mesons formed by a bound state of a charm quark and a charm anti-quark are generally known as "charmonium". The
J/ψ
is most common form of charmonium, due to its low rest mass. The
J/ψ
has a rest mass of 3.0969 GeV/c2, just above that of the
η
c (2.9836 GeV/c2), and a mean lifetime of 7.2×10−21 s. This lifetime was about a thousand times longer than expected.