T meson

T mesons are hypothetical mesons composed of a top quark and one additional subatomic particle. The second subatomic particle can be either an up quark (T0), down quark (T+), strange quark (Strange T+), charm quark (Charmed T0) or bottom antiquark (Bottom T+). Because of the top quark's short lifetime, T mesons are not expected to be found in nature.

The combination of a top quark and top antiquark is not an open T meson, but rather a closed top-quark meson called toponium. Each T meson has an antiparticle that is composed of a top antiquark and an up (Antit0), down (T-), strange (Strange T-), charm quark (Charmed antiT0) or bottom quark (Bottom T-) respectively.