eta-c meson

Related to eta-c meson: eta prime meson

e·ta-c meson

E0224550 (ā′tə-sē′, ē′tə-)n. An electrically neutral meson composed of a charm quark and a charm antiquark and having a mass 5,832 times that of the electron and a mean lifetime of about 2.6 × 10-23 second.