[en] Gluons are particles that generate the strong interaction among quarks and maintain the cohesiveness of the proton. Glueballs are systems made up of gluons and numerous physicists think that glueballs have been yet created in particle accelerators despite their short lifetime (10^-24 s), various detected elements whose mass ranges from 1500 to 1800 MeV are thought to be glueballs. In 1972 H. Fritzsch and M.Gell-Mann predicted the existence of glueballs as the only formation of gluons involving no quarks. (A.C.)