Upsilon meson
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. | |
| Composition | bb |
|---|---|
| Statistics | Bosonic |
| Family | Mesons |
| Interactions | Strong, weak, electromagnetic, gravity |
| Symbol | ϒ |
| Antiparticle | Self |
| Discovered | E288 experiment (1977) |
| Types | 1 |
| Mass | 9.46030(26) GeV/c2 |
| Mean lifetime | 1.21×10−20 s |
| Electric charge | 0 e |
| Spin | 1 |
| Isospin | 0 |
| Hypercharge | 0 |
| Parity | -1 |
| C parity | -1 |
The Upsilon meson (ϒ) 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 1.21×10−20 s and a mass about 9.46 GeV/c2 in the ground state.
- Quark structure of the Upsilon meson
